Method and device for supporting in-device coexistence in wireless LAN system

Abstract

A method and a device for operating in a wireless LAN system are disclosed. The method performed by a non-access point (AP) multi-link device (MLD), according to one embodiment of the present disclosure, may comprise steps in which a first STA affiliated in a non-AP MLD: receives, from the AP MLD, a first frame for requesting first information related to whether in-device coexistence (IDC) occurs for each link during a transmission opportunity (TXOP); transmits, to the AP MLD, a second frame including an identifier (ID) of a first link in which the IDC occurs during the TXOP from among the plurality of links; and receives, from the AP MLD, third information related to padding for switching of reception capability related to the first link.

Description

Method and device for supporting intra-terminal coexistence in a wireless LAN system

[0001] The present disclosure relates to communication operations in a wireless local area network (WLAN) system, and more specifically, to a method and device for supporting in-device coexistence (IDC) in a next-generation wireless LAN system.

[0002] New technologies have been introduced for wireless local area networks (WLANs) to improve transmission rates, increase bandwidth, improve reliability, reduce errors, and reduce latency. Among WLAN technologies, the IEEE (Institute of Electrical and Electronics Engineers) 802.11 series of standards can be referred to as Wi-Fi. For example, recently introduced technologies for WLANs include enhancements for Very High Throughput (VHT) in the 802.11ac standard, enhancements for High Efficiency (HE) in the IEEE 802.11ax standard, and enhancements for Extremely High Throughput (EHT) to provide a more advanced wireless communication environment.

[0003] For example, technologies are being studied for increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, including Multiple Input Multiple Output (MIMO) and multi-access point (AP) coordination. In particular, various technologies are being explored to support low-latency or real-time traffic. Furthermore, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technology.

[0004] The technical problem of the present disclosure is to provide a method and device for supporting IDC in a wireless LAN system.

[0005] The technical problem of the present disclosure is to provide a method and device for supporting IDC based on multi-link operation.

[0006] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0007] According to one embodiment of the present disclosure, a method performed by a non-access point (AP) multi-link device (MLD) may include: receiving, by a first STA affiliated with the non-AP MLD, from an AP MLD a first frame requesting first information related to whether in-device coexistence (IDC) will occur per link during a transmission opportunity (TXOP); transmitting, by the first STA, to the AP MLD a second frame including an identifier (ID) of a first link among a plurality of links in which IDC will occur during the TXOP; and receiving, by the first STA, from the AP MLD third information related to padding for switching a reception capability related to the first link.

[0008] In another embodiment of the present disclosure, a method performed by an access point (AP) multi-link device (MLD) may include: transmitting, by a first AP affiliated to the AP MLD, to a non-AP MLD, a first frame requesting first information related to whether in-device coexistence (IDC) will occur per link during a transmission opportunity (TXOP); receiving, by the first AP, from the non-AP MLD, a second frame including an identifier (ID) of a first link among a plurality of links in which IDC will occur during the TXOP; and transmitting, by the first AP, to the non-AP MLD, third information related to padding for switching a reception capability associated with the first link.

[0009] According to various embodiments of the present disclosure, a method and device for supporting IDC in a wireless LAN system can be provided.

[0010] According to various embodiments of the present disclosure, a method and apparatus for supporting IDC based on multi-link operation can be provided.

[0011] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0012] The accompanying drawings, which are incorporated in and are part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and, together with the detailed description, describe the technical features of the present disclosure.

[0013] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0014] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0015] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0016] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0017] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0018] FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0019] FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0020] FIG. 8 is a flowchart illustrating a method performed by a non-AP MLD according to one embodiment of the present disclosure.

[0021] FIG. 9 is a flowchart illustrating a method performed by AP MLD according to one embodiment of the present disclosure.

[0022] FIG. 10 and FIG. 11 are diagrams for explaining a control frame exchange procedure according to one embodiment of the present disclosure.

[0023] FIG. 12 and FIG. 13 are diagrams for explaining a method of performing data transmission and reception operations without switching reception capabilities according to one embodiment of the present disclosure.

[0024] FIG. 14 and FIG. 15 are diagrams for explaining a method of performing data transmission and reception operations by switching reception capabilities according to one embodiment of the present disclosure.

[0025] FIG. 16 and FIG. 17 are diagrams for explaining a method of performing data transmission and reception operations by switching reception capabilities according to one embodiment of the present disclosure.

[0026] FIG. 18 and FIG. 19 are diagrams for explaining the NSTR operation of a non-AP MLD according to one embodiment of the present disclosure.

[0027] FIG. 20 and FIG. 21 are diagrams illustrating a method for performing an operation of a non-AP MLD with defined padding according to one embodiment of the present disclosure.

[0028] FIG. 22 and FIG. 23 are diagrams illustrating a method for performing an operation of a non-AP MLD with defined padding according to one embodiment of the present disclosure.

[0029] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, one of ordinary skill in the art will appreciate that the present disclosure may be practiced without these specific details.

[0030] In some cases, to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device.

[0031] 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.

[0032] In this disclosure, terms such as “first,” “second,” etc. are used only to distinguish one component from another and are not used to limit the components, and do not limit the order or importance between the 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.

[0033] 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.

[0034] 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 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 based on the newly proposed IEEE 802.11bn (or UHR) standard. Additionally, the examples of the present disclosure can be applied to a wireless LAN based on the next-generation standard after IEEE 802.11bn. Furthermore, the examples of the present disclosure can be applied to a cellular wireless communication system. For example, the examples of the present disclosure can be applied to a cellular wireless communication system based on the LTE (Long Term Evolution) series of technologies and the 5G NR (New Radio) series of technologies of the 3rd Generation Partnership Project (3GPP) standard.

[0035] Below, technical features to which examples of the present disclosure can be applied are described.

[0036] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0037] The first device (100) and the second device (200) illustrated in FIG. 1 may be replaced with various terms such as a terminal, a wireless device, a WTRU (Wireless Transmit Receive Unit), a UE (User Equipment), an MS (Mobile Station), a UT (user terminal), an MSS (Mobile Subscriber Station), an MSS (Mobile Subscriber Unit), an SS (Subscriber Station), an AMS (Advanced Mobile Station), a WT (Wireless terminal), or simply a user. In addition, the first device (100) and the second device (200) may be replaced with various terms such as an access point (AP), a BS (Base Station), a fixed station, a Node B, a BTS (Base Transceiver System), a network, an AI (Artificial Intelligence) system, an RSU (road side unit), a repeater, a router, a relay, a gateway, etc.

[0038] 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.

[0039] Referring to FIG. 1, the first device (100) and the second device (200) can transmit and receive wireless signals through various wireless LAN technologies (e.g., IEEE 802.11 series). The first device (100) and the second device (200) can include interfaces for a medium access control (MAC) layer and a physical layer (PHY) that follow the provisions of the IEEE 802.11 standard.

[0040] In addition, the first device (100) and the second device (200) may additionally support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) other than wireless LAN technology. In addition, the device of the present disclosure may be implemented as various devices such as a mobile phone, a vehicle, a personal computer, an AR (Augmented Reality) device, a VR (Virtual Reality) device, 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).

[0041] A first device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more 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 / signals, and then transmit a wireless signal including the first information / signals via the transceivers (106). Furthermore, the processor (102) may receive a wireless signal including second information / signals via the transceivers (106), and then store information obtained from signal processing of the second information / signals 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., IEEE 802.11 series). The 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. In the present disclosure, a device may also mean a communication modem / circuit / chip.

[0042] The second device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (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 memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). Furthermore, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals 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 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 (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The 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. In the present disclosure, a device may also mean a communication modem / circuit / chip.

[0043] Hereinafter, the hardware elements of the device (100, 200) will be described in more detail. Although not limited thereto, 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 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 operational 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 operational 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 or information according to the functions, procedures, proposals and / or methods disclosed in the present 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 or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure.

[0044] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, proposals, methods and / or operation flowcharts disclosed in this disclosure may be implemented using firmware or software configured to perform one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods and / or operation flowcharts disclosed in this disclosure may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0045] 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 ROM, RAM, EPROM, 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.

[0046] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., as mentioned 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, wireless signals / channels, etc., as mentioned 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, or wireless signals 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, or wireless signals 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, wireless signals / channels, or the like, as referred to 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 may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can 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 user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0047] For example, one of the STAs (100, 200) may perform the intended operation of an AP, and the other of the STAs (100, 200) may perform the intended operation of a non-AP STA. For example, the transceivers (106, 206) of FIG. 1 may perform transmission and 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.). In addition, in the present disclosure, operations in which various STAs generate transmission and reception signals or perform data processing or calculations in advance for transmission and reception signals may be performed in the processors (102, 202) of FIG. 1. For example, an example of an operation for generating a transmission / reception signal or performing data processing or operation in advance for a transmission / reception signal may include 1) an operation for determining / obtaining / configuring / computing / decoding / encoding bit information of a field (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in a PPDU, 2) an operation for determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) used for a field (SIG, STF, LTF, Data, etc.) included in a PPDU, 3) an operation for determining / configuring / obtaining a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an extra sequence applied to SIG) used for a field (SIG, STF, LTF, Data, etc.) included in a PPDU, 4) a power control operation and / or a power saving operation applied to an STA, 5) an operation related to determining / obtaining / configuring / computing / decoding / encoding an ACK signal, etc. Additionally, in the examples below, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / computing / decoding / encoding transmission / reception signals can be stored in the memory (104, 204) of FIG. 1.

[0048] 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.

[0049] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0050] The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports transparent STA mobility to the upper layer can be provided. 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 (BSS1 and BSS2) and the inclusion of two STAs as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). 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 a BSA, it cannot directly communicate with other STAs within the BSA.

[0051] If we do not consider the DS illustrated in Figure 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, BSS1 consisting of only STA1 and STA2, or BSS2 consisting of only STA3 and STA4, can be representative examples of an IBSS, respectively. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, in this type of WLAN, a LAN can be configured when needed rather than being planned in advance, and this can 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 distributed systems (DS) is not permitted, forming a self-contained network.

[0052] 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).

[0053] In a wireless LAN, the direct STA-to-STA distance can 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 distributed system (DS) can be configured.

[0054] 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 a distributed system medium (DSM). 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.

[0055] 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).

[0056] An AP is an entity that enables access to a DS through a WM for associated non-AP STAs and also has the functionality of an STA. Data movement between a BSS and a DS can be performed through an AP. For example, STA2 and STA3 illustrated in FIG. 2 have the functionality of an STA and provide the function of allowing associated non-AP STAs (STA1 and STA4) 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 a WM and the address used by an AP for communication on a DSM do not necessarily have to be the same. A BSS consisting of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0057] Data transmitted from one of the STA(s) associated with an AP to the STA address of that AP may always be received on an uncontrolled port and processed by an IEEE 802.1X port access entity. In addition, if the controlled port is authenticated, the transmitted data (or frame) may be forwarded to the DS.

[0058] In addition to the structure of the DS described above, an extended service set (ESS) may be established to provide wider coverage.

[0059] An ESS is a network of arbitrary size and complexity, consisting of DSs and BSSs. An ESS 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 Logical Link Control (LLC) layer. STAs within an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs within an ESS may have the same SSID (service set identification). The SSID is distinct from the BSSID, which is the identifier of the BSS.

[0060] 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 limit 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 with one (or more) ESS networks. This can occur in cases where an ad-hoc network operates at 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.

[0061] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0062] For an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and complete security authentication procedures. The link setup process can also be referred to as the session initiation process or session setup process. Furthermore, the discovery, authentication, association, and security setup processes of the link setup process can be collectively referred to as the association process.

[0063] In step S310, 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.

[0064] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation including 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.

[0065] 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 so that the STA performing the scanning can 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.

[0066] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation of step S340 described below.

[0067] 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 frame used for the authentication request / response corresponds to a management frame.

[0068] 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.

[0069] An STA can send 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.

[0070] After the STA is successfully authenticated, an association process may be performed in step S330. 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.

[0071] For example, the association request frame may include information about various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an 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 may be replaced by other information or include additional information.

[0072] After the STA successfully joins the network, a security setup process may be performed in step S340. The security setup process in step S340 may be referred to as an authentication process through a Robust Security Network Association (RSNA) request / response, the authentication process in step S320 may be referred to as a first authentication process, and the security setup process in step S340 may also be referred to simply as an authentication process.

[0073] The security setup process of step S340 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.

[0074] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0075] In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). The CSMA / CA mechanism, 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 may perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time period (e.g., a DCF Inter-Frame Space (DIFS)) before starting transmission. If the sensing result determines that the medium is in an idle state, the AP and / or STA may start 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 delay period (e.g., a random backoff period) for medium access before attempting to transmit frames. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

[0076] In addition, the IEEE 802.11 MAC protocol provides the Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method that periodically polls all receiving APs and / or STAs to ensure that they receive data frames. In addition, the HCF has the Enhanced Distributed Channel Access (EDCA) and the HCF Controlled Channel Access (HCCA). The EDCA is a contention-based access method for a provider to provide data frames to multiple users, while the HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, the HCF includes a medium access mechanism to improve the Quality of Service (QoS) of the wireless LAN, and can transmit QoS data in both the Contention Period (CP) and the Contention Free Period (CFP).

[0077] Referring to Fig. 4, an operation based on a random backoff period is described. When a medium that was occupied / busy changes to an idle state, multiple STAs can attempt to transmit data (or frames). To minimize collisions, each STA can 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 can 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 given an initial value of CWmin, but can take a value doubled in case of transmission failure (e.g., when an ACK for a transmitted frame is not received). When the CW parameter value becomes CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and if data transmission is successful, it is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are 2. n It is desirable to set it to -1 (n=0, 1, 2, ...).

[0078] 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.

[0079] In the example of FIG. 4, when a packet to be transmitted reaches the MAC of STA3, STA3 can immediately transmit a 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 a random backoff count value selected by each STA after waiting for DIFS if the medium is monitored as 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 they had stopped. That is, they can start transmitting frames after counting down the remaining backoff slots equal to the remaining backoff time. Since STA5's remaining backoff time is shorter than STA1's, STA5 starts transmitting frames. While STA2 occupies the medium, STA4 may also have data to transmit. From STA4's perspective, when the medium becomes idle, it waits for DIFS, counts down according to its selected random backoff count value, and then starts transmitting frames. In the example of Figure 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.

[0080] As in the example of Fig. 4, a data frame is a frame used for transmitting data forwarded to a higher 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 that is not forwarded to a higher layer, and is transmitted after a backoff performed after an IFS elapses, such as DIFS or PIFS (Point coordination function IFS). Subtype frames of a management frame include a beacon, an association request / response, a re-association request / response, a probe request / response, and an authentication request / response. A control frame is a frame used to control access to the medium. The subtype frames of the control frame include Request-To-Send (RTS), Clear-To-Send (CTS), Acknowledgment (ACK), Power Save-Poll (PS-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP), and Trigger. 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). The type and subtype of the frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0081] 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.

[0082] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0083] 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 receiving 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.

[0084] In the example of FIG. 5, it is assumed that STA1 wants to transmit data to STA2, and STA3 is in a position to overhear some or all of the frames transmitted and received between STA1 and STA2.

[0085] 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 results. 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 results. 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.

[0086] 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 a network allocation vector (NAV) timer.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0091] The PHY layer can prepare an MPDU (MAC PDU) to be transmitted based on an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when a command requesting the start of transmission of the PHY layer is received 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 monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception of the PHY layer.

[0092] 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) format is defined.

[0093] A basic PPDU 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) as illustrated in FIG. 7) PPDU format may consist of only the Legacy-STF (L-STF), Legacy-LTF (L-LTF), Legacy-SIG (L-SIG) fields, and a Data field. Additionally, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF, (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the data field. More specific details will be described later with reference to FIG. 7.

[0094] STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, and precise time synchronization, while LTF is a signal for channel estimation, frequency error estimation, etc. STF and LTF can be said to be signals for synchronization and channel estimation of the OFDM physical layer.

[0095] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field may consist of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may include information about the modulation and coding rate of data. For example, the 12-bit Length field may include information about the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of the PPDU. For example, for a non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDU, the value of the Length field can be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0096] 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.

[0097] 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 format.

[0098] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to a time for transmitting the corresponding frame, etc. The Address subfields may indicate the receiver address, transmitter address, destination address, and source address of the frame, and some Address subfields may be omitted. For specific details of each subfield of the MAC header, including the Sequence Control, QoS Control, and HT Control subfields, refer to the IEEE 802.11 standard document.

[0099] The Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and, if additionally present, non-legacy SIG, non-legacy STF, and non-legacy LTF) in the general PPDU format, and does not include the remaining part (i.e., data field).

[0100] FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0101] Standards such as IEEE 802.11a / g / n / ac / ax use various PPDU formats. The basic PPDU format (IEEE 802.11a / g) 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 (Fig. 7(a)).

[0102] The HT PPDU format (IEEE 802.11n) 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(b) may be referred to as an HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format that does not include L-STF, L-LTF, and L-SIG, but consists of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTF, and Data fields (not illustrated).

[0103] An example of the VHT PPDU format (IEEE 802.11ac) includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).

[0104] An example of a HE PPDU format (IEEE 802.11ax) 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 (Fig. 7(d)). 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 8us. 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 may vary to 16us. For example, RL-SIG can be configured identically to L-SIG. The receiving STA can determine that the received PPDU is a HE PPDU or an EHT PPDU, described later, based on the presence of RL-SIG.

[0105] The EHT PPDU format may include the EHT MU (multi-user) PPDU of FIG. 7(e) and the EHT TB (trigger-based) PPDU of FIG. 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an RL-SIG following an L-SIG, but may include a U (universal)-SIG, an EHT-SIG, an EHT-STF, and an EHT-LTF following the RL-SIG.

[0106] The EHT MU PPDU in FIG. 7(e) corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0107] The EHT TB PPDU of Fig. 7(f) omits the EHT-SIG compared to the EHT MU PPDU. An STA that has received a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0108] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated to allow legacy STAs to attempt demodulation and decoding, and mapped based on a predetermined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated to allow STAs that have successfully decoded non-legacy SIGs (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in the fields, and mapped based on a predetermined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0109] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields may be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as pre-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields may be referred to as VHT modulation fields.

[0110] The U-SIG included in the EHT PPDU format of FIG. 7 can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 us, and the U-SIG can have a total duration of 8 us. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0111] U-SIGs can be configured in 20MHz units. For example, when an 80MHz PPDU is configured, the same U-SIG can be duplicated in 20MHz units. That is, four identical U-SIGs can be included in an 80MHz PPDU. When the bandwidth exceeds 80MHz, for example, for a 160MHz PPDU, the U-SIGs in the first 80MHz unit and the U-SIGs in the second 80MHz unit can be different.

[0112] For example, A uncoded bits may be transmitted via U-SIG, and a first symbol of U-SIG (e.g., a U-SIG-1 symbol) may transmit the first X bits of information out of a total A bits of information, and a second symbol of U-SIG (e.g., a U-SIG-2 symbol) may transmit the remaining Y bits of information out of a total A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a field of 4 bits in length) and a tail field (e.g., a field of 6 bits in length). The tail field may be used to terminate the trellis of the convolutional decoder and may be set to 0, for example.

[0113] The A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in a new PPDU format (e.g., UHR PPDU format) not shown in FIG. 7, and in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits can be the same, and some or all of the version-dependent bits can be different.

[0114] For example, the size of the version-independent bits of U-SIG can be fixed or variable. The version-independent bits can be assigned only to U-SIG-1 symbols, or to both U-SIG-1 symbols and U-SIG-2 symbols. The version-independent bits and the version-dependent bits can be called by various names, such as the first control bit and the second control bit.

[0115] For example, the version-independent bits of the U-SIG may include a 3-bit PHY version identifier, which may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted and received PPDUs. The version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value of the UL / DL flag field relates to DL communication. The version-independent bits of the U-SIG may include information about the length of a transmission opportunity (TXOP) and information about a BSS color ID.

[0116] For example, the version-dependent bits of the U-SIG may contain information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0117] Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information about bandwidth, information about the MCS technique applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether a dual carrier modulation (DCM) technique (e.g., a technique to achieve an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, information about whether the non-legacy SIG is generated across the entire band, etc.

[0118] Some of the information required for transmitting and receiving a PPDU may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of the non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-legacy LTF and the cyclic prefix (CP) length, information about the guard interval (GI) applicable to the non-legacy LTF, information about preamble puncturing applicable to the PPDU, information about resource unit (RU) allocation, etc. may be included only in the U-SIG, may be included only in the non-legacy SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-legacy SIG.

[0119] Preamble puncturing may refer to the transmission of a PPDU in which no signal is present in one or more frequency units within the PPDU's bandwidth. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth greater than a certain size.

[0120] In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. The non-legacy SIG may be transmitted over at least one symbol, and each symbol may have a length of 4 us. Information regarding the number of symbols used for the EHT-SIG may be included in a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0121] Non-legacy SIGs, such as HE-SIG-B and EHT-SIG, may contain common fields and user-specific fields. Common and user-specific fields may be coded separately.

[0122] In some cases, common fields may be omitted. For example, in a compressed mode where non-OFDMA (orthogonal frequency multiple access) is applied, common fields may be omitted, and multiple STAs may receive PPDUs (e.g., data fields of PPDUs) over the same frequency band. In a non-compressed mode where OFDMA is applied, multiple users may receive PPDUs (e.g., data fields of PPDUs) over different frequency bands.

[0123] The number of user-specific fields can be determined based on the number of users. A single user block field can contain up to two user fields. Each user field can be associated with either MU-MIMO allocation or non-MU-MIMO allocation.

[0124] The common field may include CRC bits and Tail bits, the length of the CRC bits may be determined as 4 bits, and the length of the Tail bits may be determined as 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the location of RUs to which multiple users (i.e., multiple receiving STAs) are allocated.

[0125] An RU can contain multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA techniques. RUs can also be defined when transmitting signals to a single STA. Resources can be allocated on an RU basis for non-legacy STFs, non-legacy LTFs, and data fields.

[0126] Depending on the PPDU bandwidth, an applicable RU size can be defined. The RU may be defined identically or differently for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU arrangements of HE PPDU and EHT PPDU may be different. The applicable RU size, RU number, RU position, DC (direct current) subcarrier position and number, null subcarrier position and number, guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, a tone plan for a wide bandwidth can be defined in the form of multiple repetitions of a low bandwidth tone plan.

[0127] RUs of different sizes can be defined, such as 26-ton RU, 52-ton RU, 106-ton RU, 242-ton RU, 484-ton RU, 996-ton RU, 2X996-ton RU, 3X996-ton RU, etc. A multiple RU (MRU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs. For example, one MRU can be defined as 52+26-tons, 106+26-tons, 484+242-tons, 996+484-tons, 996+484+242-tons, 2X996+484-tons, 3X996-tons, or 3X996+484-tons. Additionally, multiple RUs constituting one MRU may or may not be consecutive in the frequency domain.

[0128] The specific size of an RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in the present disclosure is not limited and is exemplary. Furthermore, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, etc.) in the present disclosure, the number of RUs may vary depending on the RU size.

[0129] The names of each field in the PPDU formats of FIG. 7 are exemplary and the scope of the present disclosure is not limited by those names. Furthermore, the examples of the present disclosure can be applied not only to the PPDU format exemplified in FIG. 7, but also to a new PPDU format in which some fields are excluded and / or some fields are added based on the PPDU formats of FIG. 7.

[0130] Procedures related to IDC (in-device coexistence)

[0131] Devices (e.g., smartphones, laptops, etc.) that utilize wireless LAN-based transmission capabilities (e.g., Wi-Fi transmission) in unlicensed bands share the unlicensed bands with one or more other transmission technologies (e.g., Bluetooth Low Energy (BLE)). When more than one transmission technology coexists in the same band, or when data transmission and reception based on more than one transmission technology occur in the same band, an interference-free communication (IDC) situation can occur. If IDC is not handled efficiently, performance degradation due to interference between different transmission technologies can occur.

[0132] The present disclosure relates to a method for efficiently handling IDC situations where transmissions other than WLAN-based transmissions are expected during a time period, frequency band, or / and space during which WLAN-based transmissions (e.g., Wi-Fi transmissions) are performed. In particular, an IDC method in a multi-link operation (MLO) situation in which transmission and reception operations based on more than one link are performed will be specifically described.

[0133] MLO enables operation between two multi-link devices (MLDs). Each STA affiliated with an MLD may be, but is not limited to, an EHT or / and UHR STA. An MLD is a logical entity, has two or more associated STAs, and may have a single medium access control service access point for logical link control, which may include one MAC data service.

[0134] AP MLD may refer to an MLD in which all associated STAs are APs, and non-AP MLD may refer to an MLD in which all associated STAs are non-AP STAs. As an example of the present disclosure, an MLD may not necessarily include multiple wireless devices. In a next-generation wireless LAN system, a single-link / wireless non-AP MLD that supports operation on more than one link but receives or transmits frames on one link at a time may be supported.

[0135] As an example of the present disclosure, when MLO is applied / performed, the device may operate in simultaneous transmission reception (STR) mode or non-STR (NSTR) mode depending on the characteristics of the device.

[0136] A multi-link single radio (MLSR) can have a single radio capable of transmitting and receiving over a single link at a time. An enhanced MLSR has a single radio with the additional capability of receiving on two links simultaneously.

[0137] A multi-link, multi-radio (muli-link, multi-radio) can have more than one radio over multiple links. The NSTR MLMR has multiple radios and can support simultaneous TX / TX and RX / RX over multiple links. The STR MLMR has multiple radios and can support TX / TX, RX / RX, TX / RX, and RX / TX over multiple links.

[0138] Various embodiments of the present disclosure may be applied to, but are not limited to, two links. Various embodiments of the present disclosure may also be extended to more than two links.

[0139] Meanwhile, in the event of link unavailability, MLO can ensure that the transmission and reception capabilities allocated for that link are transferred and used on another link without IDC. Below, we describe IDC-related procedures and methods based on MLO and the transmission and reception capabilities of wireless LAN devices.

[0140] FIG. 8 is a flowchart illustrating a method performed by a non-AP MLD according to one embodiment of the present disclosure.

[0141] As described above, at least one non-AP STA may belong to a non-AP MLD, and the operation of the non-AP MLD may include operations performed by at least one non-AP STA. In addition, at least one AP may belong to an AP MLD, and the operation of the AP MLD may include operations performed by at least one AP.

[0142] A first STA belonging to a non-AP MLD may receive a first frame requesting first information related to whether in-device coexistence (IDC) will occur per link during a TXOP from an AP MLD (e.g., at least one AP belonging to the AP MLD) (S810).

[0143] At this time, if the AP MLD is a TXOP holder, the first frame can be transmitted by at least one AP belonging to the AP MLD. If the non-AP MLD is a TXOP holder, the first frame can be transmitted to at least one AP belonging to the AP MLD. That is, the holder of the TXOP can be a non-AP MLD (e.g., the first STA) or an AP MLD (e.g., at least one AP).

[0144] For example, the first frame (or request frame) may be, but is not limited to, a first control frame or an IDC multi-link request-to-send (RTS) trigger frame.

[0145] Specifically, the first frame may include information about multiple links to be used during the TXOP (e.g., identifiers of the multiple links, etc.). Furthermore, the first information included in the first frame may include an ID of a link for requesting information about whether an IDC has occurred (e.g., a link ID for inquiring about whether an IDC has occurred).

[0146] For example, if all of the multiple link IDs are included in the first information, this may mean that the AP MLD has requested information about whether IDC has occurred on all links from a non-AP MLD (e.g., the first STA). If all of the link IDs of one or more of the multiple links are included in the first information, this may mean that the AP MLD has requested information about whether IDC has occurred on one or more links from a non-AP MLD (e.g., the first STA).

[0147] The first STA may transmit a second frame to the AP MLD, which includes an identifier (ID) of the first link where IDC will occur during a TXOP among multiple links (S820). Here, the second frame (or response frame) may be, but is not limited to, a second control frame or an IDC CTS (clear-to-send) frame.

[0148] As described above, the first STA may transmit information (e.g., ID) about the link(s) on which the TXOP will occur to the AP MLD via a second frame (e.g., a response frame), but is not limited thereto. The first STA may transmit information about whether an IDC has occurred for each link to the AP MLD via different response frames.

[0149] In describing the present disclosure, the occurrence of IDC may mean a situation in which one or more transmission technologies (e.g., a wireless LAN communication-based transmission technology and another type of transmission technology, etc.) coexist in the same band or data transmission and reception based on one or more transmission technologies are performed in the same band.

[0150] As an example of the present disclosure, the second frame may include information on whether an IDC occurs in the first link, or at least one of the time, duration, or period of an IDC occurrence in the first link.

[0151] For example, the second frame may include an indicator or bitmap related to whether IDC occurs for multiple links. For example, each bit of the bitmap may correspond to each link. If the first bit value corresponding to the first link in the bitmap is 1 (or 0), this may indicate that IDC will occur in the first link. If the first bit value corresponding to the first link in the bitmap is 0 (or 1), this may indicate that IDC will not occur in the first link.

[0152] However, this is only one embodiment, and an indicator (sub)field indicating whether an IDC occurred in the first link may be included in the second frame.

[0153] The first STA may receive a third frame from the AP MLD, which includes third information related to padding for switching reception capabilities associated with the first link (S830). Here, the third frame may be, but is not limited to, a third control frame or an IDC confirmation frame.

[0154] As an example of the present disclosure, the receiving capability associated with the first link may include, but is not limited to, at least one of a modulation and coding scheme (MCS) or a number of spatial streams of the first link.

[0155] For example, the third information may include at least one of information regarding the presence of padding, the length of the padding, the point in time at which the padding is applied, or the number of repetitions of the padding. Here, the presence of padding may be determined based on, but is not limited to, the ratio of the interval length of the TXOP and the interval length of the IDC to be generated on the first link.

[0156] As an example of the present disclosure, a first STA may receive data from an AP MLD via at least one link (e.g., a first link and a second link). In this case, if an IDC occurs on the first link, padding may be set on the first link or the second link for a specific time period (e.g., a time period equal to the length of the padding) based on the time when the IDC occurs or will occur on the first link. In this case, the specific time period may be after the time when the IDC occurs on the first link.

[0157] As another example, the second information may identify the point in time when an IDC occurs and / or the link on which the IDC will occur by the first STA and AP MLD. Accordingly, padding may be set prior to the point in time when an IDC occurs on the first link.

[0158] In addition, the first STA can switch the reception capability associated with the first link to a second link among the multiple links where IDC does not occur during a time period corresponding to the padding. The first STA can perform a data reception operation from the AP MLD on the second link based on the switched reception capability. For example, the first STA can perform an improved reception operation on the second link by utilizing the MCS, spatial stream, reception power, etc. applied to the first link.

[0159] Additionally, the first STA may perform a transmission operation related to the IDC (e.g., a transmission operation based on a communication system different from the wireless LAN communication system).

[0160] Additionally or alternatively, padding may be for the time required to switch from a transmit operation or receive operation of the second link to a receive operation or a transmit operation. The description of padding for switching receive capabilities associated with the first link may correspond to padding for a transmit-receive transition (e.g., switching from a transmit operation to a receive operation or from a receive operation to a transmit operation).

[0161] For example, a first STA may receive data from the AP MLD via the first link and the second link, respectively. If an IDC occurs on the first link, the first STA may stop receiving data on the first link and transmit data to the AP MLD via the second link. At this time, padding may be set on the first or second link for a specific period of time based on the time at which the IDC occurs on the first link.

[0162] Additionally or alternatively, the third frame may include both information related to padding for switching the receiving capability associated with the first link (e.g., first padding) and information related to padding for switching the transmitting and receiving capability (e.g., second padding), wherein both the first padding and the second padding may be applied.

[0163] The method described in the example of FIG. 8 may be performed by the first device (100) of FIG. 1. For example, one or more processors (102) of the first device (100) of FIG. 1 may receive, from the AP MLD, through one or more transceivers (106), a first frame requesting first information related to whether IDC will occur for each link during TXOP. The one or more processors (102) may transmit, to the AP MLD, through one or more transceivers (106), a second frame including an ID of a first link among a plurality of links in which IDC will occur during TXOP. The one or more processors (102) may receive, from the AP MLD, through one or more transceivers (106), third information related to padding for switching of reception capabilities related to the first link.

[0164] Furthermore, one or more memories (104) of the first device (100) may store commands for performing the method described in the example of FIG. 8 or the examples described below when executed by one or more processors (102).

[0165] FIG. 9 is a flowchart illustrating a method performed by AP MLD according to one embodiment of the present disclosure.

[0166] As described above, at least one AP may belong to an AP MLD, and operations of the AP MLD may include operations performed by at least one AP (e.g., a first AP).

[0167] A first AP affiliated with an AP MLD may transmit a first frame requesting first information regarding whether IDC will occur on each link during a TXOP to a non-AP MLD (e.g., a first STA affiliated with a non-AP MLD) (S910). Here, the configuration of the first frame has been described with reference to FIG. 8, so a redundant description will be omitted.

[0168] The first AP may receive a second frame from a non-AP MLD, which includes the ID of the first link where IDC will occur during a TXOP among multiple links (S920). Through the second frame, the first AP may identify information about the link where IDC occurs and / or the time, interval, and cycle of IDC occurrence.

[0169] The first AP may transmit a third frame containing third information related to padding for switching the reception capability associated with the first link to the non-AP MLD (S930).

[0170] For example, padding may be set for a specific time period based on the time at which an IDC occurs on the first link, and the specific time period may be before or after the time at which the IDC occurs on the first link. After the specific time period corresponding to the padding has elapsed, the first AP may perform data transmission and reception operations with a non-AP MLD over a link where an IDC did not occur.

[0171] The method described in the example of FIG. 9 may be performed by the second device (200) of FIG. 1. For example, one or more processors (202) of the second device (200) of FIG. 1 may transmit a first frame requesting first information related to whether IDC will occur for each link during TXOP to the non-AP MLD via one or more transceivers (206). The one or more processors (202) may receive, from the non-AP MLD via one or more transceivers (206), a second frame including an ID of a first link among a plurality of links in which IDC will occur during TXOP. The one or more processors (202) may transmit, to the non-AP MLD via one or more transceivers (206), a third frame including third information related to padding for switching of reception capabilities associated with the first link.

[0172] Furthermore, one or more memories (204) of the second device (200) may store commands for performing the method described in the example of FIG. 9 or the examples described below when executed by one or more processors (202).

[0173] Below, examples related to IDC-related procedures / methods based on the transmission / reception capabilities of MLO and wireless LAN devices are described in detail.

[0174] Example 1

[0175] Embodiment 1 relates to frames related to IDC and procedures for transmitting and receiving the frames. For example, the frames related to IDC may include a request frame (e.g., an IDC information request frame, etc.), a response frame (e.g., an IDC information response frame, etc.), and / or a confirmation frame (e.g., an IDC information confirmation frame, etc.). Various operations and / or parameters included in each of Embodiments 1-1 to 1-4 described below may be applied.

[0176] Example 1-1

[0177] In one embodiment of the present disclosure, an AP MLD may transmit a request frame to a non-AP MLD. The request frame may request information about whether an IDC occurs on one or more links of the non-AP MLD within a transmission opportunity (TXOP). A TXOP may refer to a time interval during which a specific QoS STA has the right to initiate a frame exchange sequence on the wireless medium. The holder of the TXOP may be an AP MLD or a non-AP MLD.

[0178] For example, the request frame may be a control frame. The control frame may be a control frame (or trigger frame) used in a basic wireless LAN system or / and a newly defined frame (e.g., an IDC-ML (multi-link) trigger frame, etc.). However, this is only an example, and the name of the request frame (or control frame) may be changed. As another example, the request frame may be an RTS frame related to IDC (e.g., an IDC-ML (multi-link)-RTS frame).

[0179] For example, a request frame (or control frame) may include information (e.g., an ID of a link) indicating which links or a subset of links (e.g., links on which IDC will occur during the TXOP) will be used during the TXOP.

[0180] That is, the request frame may include information about at least one link for the AP MLD to verify the IDC (e.g., the ID of at least one link). The non-AP MLD that receives the request frame may identify and generate IDC information corresponding to the ID of at least one link (e.g., information about whether an IDC has occurred on the link corresponding to the ID of at least one link).

[0181] Example 1-2

[0182] In one embodiment of the present disclosure, a non-AP MLD may transmit a response frame to a request frame from an AP-MLD. The response frame may include information such as whether an IDC occurred during a TXOP of the link(s) requested by the AP-MLD and information related to the IDC.

[0183] Here, the response frame may be a frame on the basic wireless LAN system, but may also be a newly defined frame. For example, the response frame may be a CTS frame (e.g., an IDC-CTS frame) containing information related to the IDC. The response frame may be transmitted on the primary link or / and for each link.

[0184] Specifically, the response frame may include information regarding whether an IDC has occurred for each link and information related to the IDC. Each of the information regarding whether an IDC has occurred and / or information related to the IDC may be set / provided via elements, fields, or subfields within the response frame. For example, whether an IDC has occurred for each link may be provided via an indicator (e.g., a 1-bit indicator), and the indicator may be set on a specific element, field, or subfield within the response frame.

[0185] As an example of the present disclosure, when the occurrence of IDC for each link is transmitted / indicated through the primary link, the occurrence of IDC for each link can be set / indicated / transmitted through a bitmap.

[0186] For example, each bit in the bitmap may correspond to each link, and whether or not IDC occurs for each link may be indicated based on the value of each bit. For example, if a specific bit value in the bitmap is 1 (or 0), this may mean that IDC will occur on the link corresponding to the bit value. As another example, if a specific bit value in the bitmap is 0 (or 1), this may mean that IDC will not occur on the link corresponding to the bit value.

[0187] Additionally or alternatively, information regarding a link ID and whether an IDC has occurred associated with that link ID may be transmitted together. For example, a response frame may include information regarding a specific link ID and whether an IDC has occurred associated with that link ID, and the information regarding a specific link ID and whether an IDC has occurred associated with that link ID may be transmitted via a single bitmap or field.

[0188] For example, if the absence of an IDC occurrence during a TXOP is indicated by an indicator indicating whether an IDC has occurred on a particular link, the response frame may not include information provided when an IDC has occurred on the particular link (e.g., information related to that IDC, etc.).

[0189] For example, information related to an IDC (e.g., information on the occurrence of an IDC) may include at least one of information on the time of occurrence of an IDC within a TXOP, an IDC duration, and an IDC occurrence cycle (e.g., if an IDC occurs periodically).

[0190] Example 1-3

[0191] In one embodiment of the present disclosure, after receiving information related to IDC from a non-AP MLD, the AP-MLD may transmit a decision regarding an action to be taken when an IDC occurs to the non-AP MLD via a control frame. Here, the control frame may be a frame that adds new information (e.g., information related to IDC, etc.) to a control frame defined in a basic wireless LAN system, but is not limited thereto. The control frame may also be a newly defined frame (e.g., an IDC information confirmation frame).

[0192] For example, the control frame may include additional information to switch some or all of the receive capabilities allocated for receive operation prior to the IDC occurrence on that link(s) to link(s) where the IDC did not occur during the TXOP (when an IDC occurs on a particular link(s)).

[0193] For example, the additional information may include information related to padding to support the time required to transition the receiving capabilities of the link(s) where IDC occurred to the link(s) where IDC did not occur. Information related to padding may include information about the presence of padding, the number of padding repetitions, the padding duration, etc. For example, if padding does not exist, information about the number of padding repetitions and / or the padding duration may be omitted.

[0194] For example, the padding may be located between data transmissions on link(s) where IDC does not occur. The start point of the padding may also be the IDC start point of the link(s) where IDC occurs.

[0195] Additionally or alternatively, the padding may be positioned prior to the IDC occurrence on the link where the IDC occurs. That is, the padding may provide time for the non-AP MLD to transition from receiving to transmitting operations. This padding may align the IDC occurrence time on a specific link with the transmission / reception time on a non-IDC link.

[0196] As an example of the present disclosure, padding information may be omitted depending on the entire TXOP interval and the ratio of the unavailability interval of links within the TXOP when an IDC occurs. That is, whether or not to omit padding information may be determined based on the "IDC interval / TXOP interval" value. For example, if the "IDC interval / TXOP interval" value is less than a predefined value (e.g., 0.3), the padding may be omitted.

[0197] As an example of the present disclosure, if IDC occurs periodically, the overhead due to the padding may be less than the time of absence of operation occurring during the IDC.

[0198] Example 1-4

[0199] In one embodiment of the present disclosure, when the operation capability of the non-AP MLD is NSTR, the AP MLD can perform a transmission operation only on a link where IDC does not occur, taking into account interference from other transmission and reception technologies performed on a link where IDC occurs.

[0200] At this time, the AP MLD and / or the non-AP MLD can switch the previously allocated reception capability for the link where the IDC occurred to the link where the IDC did not occur, so that the transmission operation can be performed in a manner having high transmission efficiency (e.g., a transmission method with a high MCS, etc. set) on the link where the IDC did not occur.

[0201] In another embodiment of the present disclosure, when the operation capability of the non-AP MLD is STR, the AP MLD can perform a transmission / reception operation on a link where IDC does not occur, taking into account interference of other transmission / reception technologies transmitted on the link where IDC occurs.

[0202] Example 2

[0203] Embodiment 2 relates to a transmission and reception procedure performed based on Embodiment 1 and detailed embodiments thereof (e.g., Embodiments 1-1, 1-2, 1-3, 1-4). That is, Embodiment 2 relates to a transmission and reception procedure based on the request frame, response frame, and confirmation frame described in Embodiment 1 and detailed embodiments thereof.

[0204] The operations of the AP MLD and non-AP MLD in Example 2 can be performed within a TXOP. At this time, the holder of the TXOP can be an AP MLD, but can also be a non-AP MLD.

[0205] FIG. 10 and FIG. 11 are diagrams for explaining a control frame exchange procedure according to one embodiment of the present disclosure.

[0206] Specifically, FIG. 10 relates to a method in which an AP MLD and a non-AP MLD exchange control frames over a primary link. An AP MLD can transmit an IDC-ML-RTS frame (e.g., a request frame related to IDC) to a non-AP MLD over the primary link. The non-AP MLD can transmit an IDC-CTS frame (e.g., a response frame to a request frame related to IDC) to the AP MLD over the primary link. The AP MLD can transmit an IDC acknowledgement frame to the non-AP MLD. The IDC-ML-RTS frame, the IDC-CTS frame, and the IDC acknowledgement frame can be transmitted and received within a TXOP.

[0207] At this time, the holder of TXOP may be an AP MLD and the responder of TXOP may be a non-AP MLD, but the holder of TXOP may be a non-AP MLD and the responder of TXOP may be an AP MLD.

[0208] Figure 11 relates to a method for an AP MLD and a non-AP MLD to exchange control frames over multiple links. As illustrated in Figure 11, an AP MLD can transmit an IDC-ML-RTS frame (e.g., a request frame related to IDC) to a non-AP MLD over the primary link via Link 1 and Link 2. The non-AP MLD can transmit an IDC-CTS frame (e.g., a response frame to a request frame related to IDC) to the AP MLD over Link 1 and Link 2. The AP MLD can transmit an IDC acknowledgement frame to the non-AP MLD over Link 1 and Link 2. The IDC-ML-RTS frame, the IDC-CTS frame, and the IDC acknowledgement frame can be transmitted and received within a TXOP.

[0209] When MLO operations due to IDC occurrence are considered / applied on a per-link basis, the IDC-ML-RTS frame may be replaced with a per-link IDC-RTS frame. In this case, the IDC-RTS frame may include, but is not limited to, information about multiple links, and information about multiple links may be omitted.

[0210] In addition, the transmission and reception times of the IDC-RTS frame, IDC-CTS frame, and / or IDC-confirm frame may be aligned for each link, but are not limited thereto. The transmission and reception times of the IDC-RTS frame, IDC-CTS frame, and / or IDC-confirm frame for each link may be individually determined / set.

[0211] FIG. 12 and FIG. 13 are diagrams for explaining a method of performing data transmission and reception operations without switching reception capabilities according to one embodiment of the present disclosure.

[0212] As illustrated in FIG. 12, the AP MLD can transmit data to the non-AP MLD via Link 1 and Link 2. At this time, if an IDC occurs in Link 2 of the non-AP MLD, the AP MLD may perform a data transmission operation via Link 1 (e.g., an operation in which the non-AP MLD receives data via Link 1 as the AP MLD transmits data via Link 1), but may not perform a data transmission operation on Link 2 in which the IDC occurred.

[0213] At this time, the non-AP MLD can perform data reception on Link 1 and IDC-related transmission (e.g., transmission based on another communication method) on Link 2 without switching the reception capability of Link 2 to Link 1. In other words, the non-AP MLD can perform STR operation without switching the reception capability.

[0214] Fig. 13 illustrates the procedure according to Fig. 12 at the frame level. That is, the description of the procedure according to Fig. 13 corresponds to the description of the procedure according to Fig. 12, and the transmission and reception procedure can be performed at the frame level according to Fig. 13.

[0215] FIG. 14 and FIG. 15 are diagrams for explaining a method of performing data transmission and reception operations by switching reception capabilities according to one embodiment of the present disclosure.

[0216] As illustrated in FIG. 14, the AP MLD can transmit data to the non-AP MLD via Link 1 and Link 2. At this time, if an IDC occurs in Link 2 of the non-AP MLD, padding can be set / defined in Link 1. For example, padding can be set / defined in Link 1 for a preset / defined time period based on the time at which the IDC occurs in Link 2.

[0217] The length of the padding can be predefined, but AP MLD and non-AP MLD can exchange frames (e.g., request frame, response frame, or / and response frame, etc.) that contain information about the length of the padding.

[0218] And, the non-AP MLD can switch / allocate the receive capability of link 2 (e.g., the receive capability configured / defined for link 2) to link 1. That is, padding can be set on link 1 as the time required for the non-AP MLD to allocate / switch the receive capability of link 2 to link 1. The non-AP MLD can receive data from the AP MLD through link 1 to which the receive capability of link 2 is switched / configured. That is, the non-AP MLD can perform an improved data reception operation (based on STR).

[0219] Figure 15 illustrates the procedure according to Figure 14 at the frame level. That is, the description of the procedure according to Figure 15 corresponds to the description of the procedure according to Figure 14, and the transmission and reception procedure can be performed at the frame level according to Figure 15.

[0220] FIG. 16 and FIG. 17 are diagrams for explaining a method of performing data transmission and reception operations by switching reception capabilities according to one embodiment of the present disclosure.

[0221] As illustrated in Figure 16, the AP MLD can transmit data to the non-AP MLD via Link 1 and Link 2. At this time, padding can be set / defined for Link 2 before an IDC occurs. That is, padding can be set / defined during a predefined time period prior to the time at which the IDC is expected to occur.

[0222] At this time, the length of the padding can be predefined, but the AP MLD and non-AP MLD can exchange frames (e.g., request frames, response frames, or / and response frames) that contain information about the length of the padding.

[0223] And, the non-AP MLD can switch / allocate the receive capability of link 2 (e.g., the receive capability configured / defined for link 2) to link 1. That is, padding can be set on link 1 as the time required for the non-AP MLD to allocate / switch the receive capability of link 2 to link 1. The non-AP MLD can receive data from the AP MLD through link 1 to which the receive capability of link 2 is switched / configured, and perform IDC-related transmission operations through link 2. That is, the non-AP MLD can perform improved data reception operations (based on STR).

[0224] Fig. 17 illustrates the procedure according to Fig. 16 at the frame level. That is, the description of the procedure according to Fig. 17 corresponds to the description of the procedure according to Fig. 16, and the transmission and reception procedure can be performed at the frame level according to Fig. 17.

[0225] FIG. 18 and FIG. 19 are diagrams for explaining the NSTR operation of a non-AP MLD according to one embodiment of the present disclosure.

[0226] As illustrated in FIG. 18, the AP MLD can transmit data to the non-AP MLD via Link 1 and Link 2. At this time, if an IDC occurs in Link 2 of the non-AP MLD, the non-AP MLD can perform an IDC-related operation in Link 2 and transmit data to the AP MLD in Link 1. That is, if an IDC occurs in Link 2, the non-AP MLD can transmit data to the AP MLD in Link 1 and perform an IDC-related transmission in Link 2. That is, the non-AP MLD can perform the NSTR operation by converting the receiving operation in Link 1 to a transmitting operation.

[0227] Fig. 19 illustrates the procedure according to Fig. 18 at the frame level. That is, the description of the procedure according to Fig. 19 corresponds to the description of the procedure according to Fig. 18, and the transmission and reception procedure can be performed at the frame level according to Fig. 19.

[0228] FIG. 20 and FIG. 21 are diagrams illustrating a method for performing an operation of a non-AP MLD with defined padding according to one embodiment of the present disclosure.

[0229] As illustrated in Figure 20, the AP MLD can transmit data to the non-AP MLD via Link 1 and Link 2. At this time, if an IDC occurs on Link 2 of the non-AP MLD, padding can be set / defined on Link 1. For example, padding of a predefined / set interval based on the time point at which the IDC occurs can be set on Link 1.

[0230] The length of the padding can be predefined, but AP MLD and non-AP MLD can exchange frames (e.g., request frame, response frame, or / and response frame, etc.) that contain information about the length of the padding.

[0231] Considering the interference of IDC in DL transmission on Link 1 of the AP MLD, the non-AP MLD can switch the receiving operation to the transmitting operation. Here, padding can be defined for the time required to switch the receiving operation on Link 1 of the non-AP MLD to the transmitting operation.

[0232] Fig. 21 illustrates the procedure according to Fig. 20 at the frame level. That is, the description of the procedure according to Fig. 21 corresponds to the description of the procedure according to Fig. 20, and the transmission and reception procedure can be performed at the frame level according to Fig. 21.

[0233] FIG. 22 and FIG. 23 are diagrams illustrating a method for performing an operation of a non-AP MLD with defined padding according to one embodiment of the present disclosure.

[0234] As illustrated in FIG. 22, the AP MLD can transmit data to the non-AP MLD via Link 1 and Link 2. At this time, padding can be set / defined on Link 1 before IDC occurs on Link 2 of the non-AP MLD. For example, padding can be set / defined up to a predefined / configured interval before the expected time point at which IDC is expected to occur on Link 2.

[0235] The length of the padding can be predefined, but AP MLD and non-AP MLD can exchange frames (e.g., request frame, response frame, or / and response frame, etc.) that contain information about the length of the padding.

[0236] Considering the interference of IDC in DL transmission on Link 1 of the AP MLD, the non-AP MLD can switch the receiving operation to the transmitting operation. Here, padding can be defined for the time required to switch the receiving operation on Link 1 of the non-AP MLD to the transmitting operation.

[0237] Figure 23 illustrates the procedure according to Figure 22 at the frame level. That is, the description of the procedure according to Figure 23 corresponds to the description of the procedure according to Figure 22, and the transmission and reception procedure can be performed at the frame level according to Figure 23.

[0238] Example 3

[0239] Embodiment 3 relates to additional or alternative operations based on Embodiment 1 (or / and detailed embodiments of Embodiment 1) and / or Embodiment 2.

[0240] As an example of the present disclosure, in an MLD operating environment, link-specific information may be transmitted to other links. It may be difficult for the AP MLD and / or the non-AP MLD to predict the link-specific TXOP timing. The non-AP MLD may transmit information related to unavailability due to IDC, which is known to the STA(s) of the non-AP MLD, to the AP MLD.

[0241] For example, information related to unavailability may include a link ID, information on whether unavailability (e.g., IDC) has occurred, time information when unavailability (e.g., IDC) has occurred (e.g., IDC occurrence start time, IDC interval, IDC cycle, etc.). Here, the time information may include information on the TSF (Timing Synchronization Function) of the corresponding link.

[0242] When an STA of a non-AP MLD of a specific link transmits data, information related to unavailability (e.g., IDC) corresponding to the specific link may be transmitted to the AP MLD via the A-control field. At this time, the A-control field may include one or more control fields, and IDC-related information may be set on some of the one or more control fields. That is, the A-control field may include one or more control fields for IDC, and the control fields defined for IDC may include an ID and / or a link ID indicating the IDC purpose.

[0243] While IDC situations can be planned in advance, they can also occur unexpectedly. Furthermore, AP MLD and / or non-AP MLD can encounter situations where it is difficult to predict the size of the IDC interval. For example, if a phone call is received through earphones connected via BLE while using the Internet via a wireless LAN signal (e.g., a Wi-Fi signal), the size of the IDC interval can be difficult to predict. In this case, the methods described below can be used to overcome these situations.

[0244] As an example of the present disclosure, when a non-AP MLD is a TXOP holder, if it recognizes that an IDC has occurred before acquiring the TXOP, the length of the TXOP can be determined (by the non-AP MLD or / and the AP MLD) so that the TXOP ends before the IDC has occurred.

[0245] As an example of the present disclosure, when a non-AP MLD is a TXOP holder and recognizes the occurrence of an IDC after acquiring a TXOP, the non-AP MLD or / and the AP MLD may reduce the length of the CF (control frame)-end transmission interval or the TXOP interval. Information for reducing the TXOP interval may be indicated / set through the A-control field of a data frame, a control frame. As an example, the non-AP MLD or / and the AP MLD may transmit and receive information for reducing the TXOP interval through frames such as BA, Multi-STA BA, etc.

[0246] As an example of the present disclosure, when the A-control field is used to transmit IDC-related information and / or information for reducing the TXOP interval, at least one control field may be included on the A-control field. In this case, the at least one control field may include information such as an ID corresponding to TXOP truncation, a link ID, and an immediate / delay time.

[0247] As an example of the present disclosure, when a non-AP STA is a TXOP responder, the non-AP STA may transmit information about the time, period, and period when unavailability (e.g., IDC) occurs to the AP through a response frame to the AP (e.g., an initial control response (ICR) or a control response frame (CRF)). Additionally or alternatively, whether or not an IDC occurs may be indicated to the AP through a control frame. Here, the control frame may be a frame of a basic wireless LAN system (e.g., a BA frame) or may include a newly defined frame.

[0248] In the event of an unexpected IDC termination, the termination of the IDC may be indicated in the manner described above. For example, a non-AP MLD (or STA) may transmit information indicating whether the IDC has been terminated to the AP (MLD) via various types of frames (e.g., control frames, etc.).

[0249] By various embodiments of the present disclosure, a more efficient operating environment (e.g., increased throughput, etc.) can be provided when an IDC situation occurs on one or more links in an MLO operating environment.

[0250] The embodiments described above are combinations of components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form embodiments of the present disclosure by combining some components and / or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form embodiments or incorporated as new claims through post-application amendments.

[0251] It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential characteristics thereof. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present disclosure are intended to be included within the scope of the present disclosure.

[0252] The scope of the present disclosure includes software or machine-executable instructions (e.g., an operating system, an application, firmware, a program, etc.) that cause operations according to the methods of various embodiments to be executed on a device or a computer, and a non-transitory computer-readable medium having such software or instructions stored thereon and executable on the device or computer. Instructions that can be used to program a processing system to perform the features described in the present disclosure can be stored on / in a storage medium or a computer-readable storage medium, and a computer program product including such a storage medium can be used to implement the features described in the present disclosure. The storage medium can include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices, and can include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory optionally includes one or more storage devices remotely located from the processor(s). The memory or, alternatively, the non-volatile memory device(s) within the memory comprise a non-transitory computer-readable storage medium. The features described in this disclosure may be incorporated into software and / or firmware stored on any of the machine-readable media, which may control the hardware of the processing system and allow the processing system to interact with other mechanisms that utilize results according to embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0253] The method proposed in this disclosure is described with a focus on examples applied to IEEE 802.11-based systems, but can be applied to various wireless LANs or wireless communication systems in addition to IEEE 802.11-based systems.

Claims

1. A method performed by a non-access point (AP) multi-link device (MLD), the method comprising: A step of receiving, by a first STA affiliated with the non-AP MLD, a first frame requesting first information related to whether in-device coexistence (IDC) will occur on a link basis during a transmission opportunity (TXOP) from the AP MLD; A step of transmitting a second frame including an identifier (ID) of a first link in which IDC will occur during the TXOP among multiple links to the AP MLD by the first STA; and A method comprising the step of receiving, by the first STA, from the AP MLD a third frame including third information related to padding for switching a reception capability associated with the first link.

2. In paragraph 1, A method in which the reception capability associated with the first link is switched to a second link among the plurality of links in which IDC does not occur.

3. In paragraph 1, The first frame includes information about the plurality of links to be used during the TXOP, A method wherein the first information includes an ID of a link for requesting information on whether the IDC occurs.

4. In paragraph 1, A method wherein the second frame includes information on whether an IDC occurs in the first link, or at least one of the time, duration, or period of an IDC occurrence in the first link.

5. In paragraph 1, A method wherein the second frame includes an indicator or bitmap related to whether or not an IDC occurs for each of the plurality of links.

6. In paragraph 2, The padding is set on the first link or the second link for a specific time period based on the time when the IDC occurs or when the IDC will occur on the first link, A method wherein the specific time period is before or after the time at which IDC occurs on the first link.

7. In paragraph 2, A method wherein the third information includes at least one of information on the presence or absence of the padding, the length of the padding, the point in time at which the padding is applied, or the number of repetitions of the padding.

8. In paragraph 2, Based on the above-mentioned converted reception capability, a data reception operation from the AP MLD in the second link is performed by the first STA, A method in which a transmission operation related to the IDC is performed by the first STA in the first link.

9. In paragraph 1, The first frame is a first control frame or an IDC multi-link RTS (request-to-send) trigger frame, The second frame is a second control frame or IDC CTS (clear-to-sned) frame, A method wherein the third frame is a third control frame or an IDC confirmation frame.

10. In paragraph 1, A method in which the presence or absence of the padding is determined based on a ratio of the interval length of the TXOP and the interval length of the IDC to be generated in the first link.

11. In paragraph 1, A method wherein the reception capability associated with the first link comprises at least one of a modulation and coding scheme (MCS) or a number of spatial streams of the first link.

12. In a first station (STA) belonging to a non-access (AP) multi-link device (MLD), the first STA: one or more transmitters and receivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Receiving a first frame requesting first information related to whether in-device coexistence (IDC) will occur on a link basis during a transmission opportunity (TXOP) from an AP MLD affiliated to the non-AP MLD through the one or more transceivers; A second frame including an identifier (ID) of a first link in which an IDC will occur during the TXOP among multiple links is transmitted to the AP MLD through the one or more transceivers; and A first STA configured to receive third information related to padding for switching reception capabilities associated with the first link from the AP MLD through the one or more transceivers.

13. A method performed by an access point (AP) multi-link device (MLD), the method comprising: A step of transmitting a first frame to a non-AP MLD by a first AP affiliated to the AP MLD, the first frame requesting first information related to whether in-device coexistence (IDC) will occur on a link basis during a transmission opportunity (TXOP); A step of receiving a second frame including an identifier (ID) of a first link in which an IDC is to occur during the TXOP among multiple links from the non-AP MLD by the first AP; and A method comprising the step of transmitting third information related to padding for switching of a reception capability associated with the first link to the non-AP MLD by the first AP.

14. In a first AP belonging to an access point (AP) multi-link device (MLD), the first AP: one or more transmitters and receivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Transmitting a first frame to a non-AP MLD via one or more transceivers, the first frame requesting first information regarding whether in-device coexistence (IDC) will occur on a link-by-link basis during a transmission opportunity (TXOP); A second frame including an identifier (ID) of a first link in which an IDC is to occur during the TXOP among multiple links is received from the non-AP MLD through the one or more transceivers; and A first AP configured to transmit third information related to padding for switching reception capabilities associated with the first link to the non-AP MLD via the one or more transceivers.

15. A processing device configured to control a first station (STA) belonging to a non-access point (AP) multi-link device (MLD) in a wireless local area network (WLAN) system, wherein the processing device: one or more processors; and A processing device comprising one or more computer memories operatively connected to said one or more processors and storing instructions for performing a method according to any one of claims 1 to 11 based on execution by said one or more processors.

16. One or more non-transitory computer-readable media storing one or more instructions, A computer-readable medium, wherein the one or more commands are executed by one or more processors to control a device in a wireless LAN system to perform a method according to any one of claims 1 to 11.

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