Method and apparatus for performing multi-access point operation in wireless LAN system

Abstract

Disclosed are a method and an apparatus for operating in a wireless LAN system. A method according to an embodiment of the present disclosure comprises the steps of: transmitting, by a first access point (AP), a schedule announcement frame to at least one AP, the schedule announcement frame comprising information related to at least one type of coordinated multi-AP (C-MAP) operation supported by the first AP within a first transmission opportunity (TXOP); receiving a first response frame corresponding to the schedule announcement frame from the second AP among the at least one AP by the first AP; and transmitting a trigger frame for the first type of C-MAP operation among the at least one type of C-MAP operation to the second AP, by the first AP The first AP may be the owner of the first TXOP.

Description

Method and device for performing multi-access point operation 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 performing multi-access point (AP) operations 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, enhance 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 and enhancements for High Efficiency (HE) in the IEEE 802.11ax standard.

[0003] To provide a more advanced wireless communication environment, improved technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for Multiple Input Multiple Output (MIMO), which supports increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, and for coordination of multiple access points (APs), are being studied. In particular, various technologies are being studied 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 performing multi-AP operation in a wireless LAN system.

[0005] The technical problem of the present disclosure is to provide a method and device for performing one or more coordinated multi-AP operations for a certain period of time.

[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 can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0007] A method according to one embodiment of the present disclosure comprises the steps of: transmitting a schedule announcement frame by a first access point (AP) to at least one AP, the schedule announcement frame including information related to at least one type of coordinated multi-AP (C-MAP) operation supported by the first AP within a first transmission opportunity (TXOP); receiving, by the first AP, a first response frame corresponding to the schedule announcement frame from a second AP of the at least one AP; and transmitting, by the first AP, a trigger frame for a first type of C-MAP operation of the at least one type of C-MAP operation to the second AP, wherein the first AP may be an owner of the first TXOP.

[0008] According to another embodiment of the present disclosure, a method comprises the steps of: receiving, by a second access point (AP), a schedule announcement frame from a first AP, the schedule announcement frame including information related to at least one type of coordinated multi-AP (C-MAP) operation supported by the first AP within a first transmission opportunity (TXOP); transmitting, by the second AP, a first response frame corresponding to the schedule announcement frame to the first AP; and receiving, by the second AP, a trigger frame for a first type of C-MAP operation among the at least one type of C-MAP operation from the first AP, wherein the first AP may be an owner of the first TXOP.

[0009] According to various embodiments of the present disclosure, a method and device for performing multi-AP operation in a wireless LAN system can be provided.

[0010] According to various embodiments of the present disclosure, a method and apparatus for performing one or more cooperative multi-AP operations for a certain period of time may 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 drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0021] FIG. 9, FIG. 10, FIG. 11, and FIG. 12 are diagrams for explaining operations when a TXOP owner is a TXOP coordinating AP of a C-SR procedure according to one embodiment of the present disclosure.

[0022] FIG. 13, FIG. 14, FIG. 15, and FIG. 16 are diagrams for explaining operations when a TXOP owner is a TXOP coordinated AP of a C-SR procedure according to one embodiment of the present disclosure.

[0023] FIG. 17, FIG. 18, FIG. 19, and FIG. 20 are diagrams for explaining operations when a TXOP owner does not participate in a C-SR operation according to one embodiment of the present disclosure.

[0024] FIG. 21 is a diagram illustrating a method for a TXOP owner to perform a C-MAP operation according to one embodiment of the present disclosure.

[0025] FIG. 22 is a flowchart illustrating a method performed by a first AP according to one embodiment of the present disclosure.

[0026] FIG. 23 is a flowchart illustrating a method performed by a second AP according to one embodiment of the present disclosure.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Below, technical features to which examples of the present disclosure can be applied are described.

[0034] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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).

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0048] 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.

[0049] 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.

[0050] 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).

[0051] 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.

[0052] 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.

[0053] 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).

[0054] 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.

[0055] 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.

[0056] In addition to the structure of the DS described above, an extended service set (ESS) may be established to provide wider coverage.

[0057] 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.

[0058] 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.

[0059] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0073] 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.

[0074] 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).

[0075] 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, ...).

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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).

[0098] FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0099] 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)).

[0100] 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).

[0101] 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)).

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.).

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.).

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] FIG. 8 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0129] A trigger frame may allocate resources for the transmission of one or more TB PPDUs and request the transmission of TB PPDUs. The trigger frame may also include other information required by the STA transmitting the TB PPDU in response. The trigger frame may include common information and a user information list field in the frame body.

[0130] The common information field may include information that is common to one or more TB PPDU transmissions requested by a trigger frame, such as trigger type, UL length, presence of a subsequent trigger frame (e.g., More TF), whether CS (channel sensing) is required, UL BW (bandwidth), etc. Fig. 8 illustrates an example of an EHT variant common information field format.

[0131] The 4-bit trigger type subfield can have values ​​from 0 to 15. Among them, the values ​​0, 1, 2, 3, 4, 5, 6, and 7 of the trigger type subfield are defined to correspond to basic, Beamforming Report Poll (BFRP), multi user-block acknowledgement request (MU-BAR), multi user-request to send (MU-RTS), Buffer Status Report Poll (BSRP), groupcast with retries (GCR), MU-BAR, Bandwidth Query Report Poll (BQRP), and NDP Feedback Report Poll (NFRP), respectively, and the values ​​8 to 15 are defined as reserved.

[0132] Among the common information, the trigger dependent common info subfield may include information that is optionally included based on the trigger type.

[0133] A special user info field may be included within the trigger frame. The special user info field does not contain user-specific information, but rather extended common information not provided in the common information field.

[0134] A user information list contains zero or more user information fields. Figure 8 illustrates an example of an EHT variant user information field format.

[0135] The AID12 subfield basically indicates that it is a user information field for an STA with the corresponding AID. In addition, if the AID12 field has a predetermined specific value, it may be utilized for other purposes, such as allocating a random access (RA)-RU, or being configured in the form of a special user information field. The special user information field is a user information field that does not contain user-specific information, but contains extended common information not provided in the common information field. For example, the special user information field can be identified by the AID12 value of 2007, and the special user information field flag subfield within the common information field can indicate whether the special user information field is included.

[0136] The RU allocation subfield can indicate the size and location of an RU / MRU. For this purpose, the RU allocation subfield can be interpreted together with the PS160 (primary / secondary 160MHz) subfield of the user information field, the UL BW subfield of the common information field, etc.

[0137] Procedure for coordinated multi-AP (C-MAP) operation

[0138] As a next-generation wireless LAN technology (e.g., UHR-based wireless LAN technology), a cooperative transmission / reception technology (e.g., C-MAP operation) between one or more APs can be applied / utilized.

[0139] Here, the MAP operation may be a general term for a technique in which multiple APs / STAs cooperate with each other to transmit and receive data when communicating with other STA(s). The MAP operation may include a first method (i.e., a multi-APs / STAs co-transmission method) in which multiple APs simultaneously transmit data to STA(s), and a second method (i.e., a multi-APs / STAs coordination method) in which an appropriate AP among multiple APs divides an appropriate area (e.g., a frequency / time / space area) and then transmits data to specific STA(s) (i.e., an appropriate STA(s)).

[0140] Transmission using cooperation between APs is advantageous in terms of efficient and fair resource management, and can support transmission of traffic requiring low latency.

[0141] For example, an AP that has acquired the right to use a channel exclusively for a certain period of time can share the right to use the channel for a certain period of time with AP(s) that support / manage another BSS (e.g., an overlapping basic service set (OBSS)).

[0142] C-MAP methods can be categorized into different types depending on how the right to use a channel is shared within a certain period of time. For example, C-MAP methods can include Coordinated Time Division Multiple Access (C-TDMA), Coordinated Spatial Reuse (C-SR), Coordinated Restricted Target Wake Time (C-RTWT), Coordinated Orthogonal Frequency Division Multiple Access (C-OFDMA), and Coordinated Beamforming (C-BF).

[0143] For example, when the C-TDMA scheme is applied, multiple APs can coordinate the time to use the channel with each other within a certain period of time and perform frame exchange during the coordinated time. When the C-SR scheme is applied, multiple APs can share channel information (e.g., transmit power (Tx power), received signal strength indicator (RSSI), etc.) with each other and perform communication at the same time based on the channel information. When the C-RTWT scheme is applied, multiple APs can coordinate the section related to the activation state (e.g., service period (SP)) within a certain period of time. When the C-OFDMA scheme is applied, multiple APs can perform frequency division operation between users according to frequency resources. When the C-BF scheme is applied, multiple APs can cooperate to perform beamforming operation.

[0144] Each C-MAP type has different advantages and disadvantages. For example, C-TDMA offers the advantage of simple operation and implementation, which can reduce overhead, but may not utilize frequency efficiently.

[0145] When more than one type of C-MAP operation is combined and used for a period of time, the advantages of each C-MAP type can be multiplied. For example, if C-TDMA and C-SR methods are supported and applied for a period of time, the convenience of C-TDMA operation and the efficiency of frequency use by C-SR can be derived.

[0146] Additionally or alternatively, each AP may support operation according to one or more C-MAP types. For example, AP 1 may support C-TDMA, C-SR, and C-RTWT, while AP 2 may support C-TDMA and C-SR. When an AP (e.g., a TXOP owner (or holder)) that has obtained the right to exclusively use a channel for a certain period of time supports one or more types of C-MAP operation, the AP may transmit information about the C-MAP method to be used during the TXOP to neighboring AP(s) (e.g., OBSS AP(s)) and receive an intent to participate in the C-MAP method from the OBSS AP(s).

[0147] The present disclosure relates to a method for supporting one or more types of C-MAP schemes and a procedure for transmitting and receiving information according to the C-MAP schemes. As an example, when an AP (e.g., a BSS AP and / or an OBSS AP) supports one or more types of C-MAP operations, the C-MAP schemes to be used during a TXOP and / or a method for transmitting and receiving information according to the C-MAP schemes are described.

[0148] Specifically, the present disclosure relates to a method for indicating whether a TXOP owner shares with other APs the right to use exclusively for a certain period of time through one or more types of C-MAP schemes, a method for indicating support for the one or more types of C-MAP schemes, a method for sharing information about C-MAP, a method for indicating whether a TXOP owner participates in one or more types of C-MAP schemes, a method for communicating coordinating and coordinated AP information related to C-MAP operations, and the like.

[0149] BSS APs and / or OBSS APs can support efficient C-MAP operation depending on channel conditions, traffic types (e.g., low-latency traffic or delay-tolerant traffic), network topology, etc.

[0150] In describing the present disclosure, a TXOP owner AP may refer to an AP that has obtained exclusive rights to use a channel for a certain period of time through channel access. A TXOP shared AP may refer to an AP that receives TXOPs from a TXOP owner. The TXOP shared AP may perform the same transmission method as the TXOP owner or a different transmission method. For example, the TXOP shared AP may use the same C-TDMA method as the TXOP owner or the C-SR method.

[0151] And, a TXOP coordinating AP may mean an AP that performs the role of a TXOP owner during a TXOP shared by the TXOP owner. A TXOP coordinated AP may mean an AP that performs the role of a TXOP shared AP during a TXOP shared by the TXOP owner. A TXOP owner may be a TXOP coordinating AP or a TXOP coordinated AP. That is, a TXOP owner may participate in C-MAP operations as a TXOP coordinating AP or a TXOP coordinated AP, or may not participate in C-MAP operations.

[0152] Example 1

[0153] Embodiment 1 relates to a method in which a TXOP owner participates in C-SR operations (e.g., C-SR-based downlink transmission) with an AP cooperating with the TXOP. Embodiment 1 relates to an example, but is not limited to, of a method in which a TXOP owner shares a TXOP with other APs by applying C-TDMA and C-SR schemes during the TXOP. In the description according to Embodiment 1, each of the C-TDMA and C-SR schemes may be replaced with another type of C-MAP scheme.

[0154] As an example of the present disclosure, as illustrated in FIG. 9, AP 1 (e.g., a TXOP owner) may transmit a schedule announcement frame (e.g., a first frame) to at least one STA in a broadcast manner. For example, the TA (transmitter address) of the schedule announcement frame may include / correspond to information about AP 1, and the RA (receiver address) may include / correspond to information about the broadcast (BC).

[0155] At least one STA to which a schedule announcement frame is transmitted may include an associated STA(s) within a BSS of AP 1, AP 2 (e.g., an OBSS AP), and / or STA(s) associated within a BSS of AP 2 (e.g., OBSS STA(s)).

[0156] As an example of the present disclosure, the schedule announcement frame may include, but is not limited to, a (MU (multi-user) request to send (RTS)) triggered TXOP shared (TXS) frame or a separate trigger frame. As an example, a variant of the TXS frame may be a new variant that indicates support for a different type of C-MAP operation during the TXOP.

[0157] The schedule announcement frame may include information indicating that a TXOP will be shared in a specific type of C-MAP operation. Additionally, the schedule announcement frame may include identification information for at least one AP with which the TXOP will be shared.

[0158] Additionally or alternatively, the schedule announcement frame may include information about the type of C-MAP operation supported by AP 1, and the information about the type of C-MAP operation may be configured in the form of an ID or a bitmap. For example, the schedule announcement frame may include a bitmap or an ID value indicating at least one type of C-MAP operation supported by AP 1 (e.g., C-SR, C-RTWT, C-OFDMA, C-BF, etc.).

[0159] For example, as illustrated in FIG. 9, assume that AP 1 transmits information indicating that AP 1 supports C-SR through a schedule announcement frame.

[0160] As an example of the present disclosure, the schedule announcement frame may include information about at least one AP participating in a C-MAP operation (e.g., a C-MAP operation indicated by the schedule announcement frame) (e.g., a C-SR operation, etc.). As an example, the schedule announcement frame may include identification information of at least one AP participating in the C-MAP operation.

[0161] For example, the identification information of at least one AP participating in the C-MAP operation may include a set ID or individual AP identification information. For example, the identification information of APs participating in a specific type of C-MAP operation may be classified into a single set ID.

[0162] For example, assume that AP 1 and AP 2 participate in C-SR operation, and AP 1 and AP 3 participate in C-RTWT operation. In this case, the schedule announcement frame may include "Set ID 1 = {AP 1, AP 2}" and "Set ID 2 = {AP 1, AP 3}", where Set ID 1 may correspond to C-SR operation, and Set ID 2 may correspond to C-RTWT operation. However, this is only an example, and the Set ID value may be set / defined differently depending on each C-MAP operation. In addition, the Set ID may be set / defined differently depending on each C-MAP operation method.

[0163] For example, if the set ID value is not pre-specified, the schedule announcement frame may include identification information for each AP(s) that will participate in the C-MAP operation indicated by the schedule announcement frame. The identification information of the AP may be defined using the MAC ID of the AP, or may be defined according to "partial MAC ID and / or BSS color", etc.

[0164] Additionally or alternatively, the schedule announcement frame may include a time point for applying (or starting) the C-MAP scheme indicated by the schedule announcement frame. Until the time point indicated by the schedule announcement frame, other AP(s) corresponding to / participating in the C-MAP operation may be in a power saving state. For example, the AP(s) participating in the C-MAP scheme may be in a power saving state until the C-MAP scheme indicated by the schedule announcement frame starts.

[0165] For example, as illustrated in FIG. 9, STA(s) of AP 1 (e.g., STA(s) included in the BSS of AP 1) and / or AP 2 that have received a schedule notification frame may transmit a CTS frame to AP 1. Then, AP 1 may perform frame exchange with the STA(s) of AP 1 according to a specific C-MAP method (e.g., C-TDMA method).

[0166] And, AP 1 can transmit the TXOP allocation frame to at least one AP. For example, as illustrated in FIG. 9, AP 1 can transmit the TXOP allocation frame to at least one AP(s) that support / participate in the C-MAP operation indicated by the schedule announcement frame. For example, as illustrated in FIG. 9, the TXOP allocation frame can be transmitted to AP 2 that supports / participates in the C-SR operation, and AP 2 can be indicated via a set ID corresponding to the C-SR operation.

[0167] Specifically, the TXOP allocation frame may include predefined identification information (e.g., set ID) for the AP(s) participating in the C-MAP operation or individual identification information of the AP(s).

[0168] Additionally, the TXOP allocation frame may include information about an AP coordinating the C-MAP operation among the AP(s) participating in the C-MAP operation. That is, the TXOP allocation frame may include information about the C-MAP operation and / or information about at least one AP that will participate in the C-MAP operation.

[0169] For example, if the TXOP owner is a cooperating AP for C-MAP operation, the coordinated AP(s) may set the RA of the response frame to the TXOP allocation frame to the identification information of the cooperating AP (e.g., the TXOP owner). As another example, if the coordinated AP(s) is a cooperating AP for C-MAP operation, the coordinated AP(s) may set the RA of the response frame to the TXOP allocation frame to the identification information of the TXOP owner AP.

[0170] Additionally or alternatively, the TXOP allocation frame may include identification information of an AP (e.g., AP 1) that will operate as a cooperating AP in C-SR operation and / or identification information of an AP (e.g., AP 2) that will operate as a cooperating AP.

[0171] As an example of the present disclosure, a TXOP allocation frame may include information about the time period of a TXOP allocated for a C-MAP operation (e.g., a C-MAP operation indicated by a schedule announcement frame). Additionally or alternatively, the TXOP allocation frame may include information about the type of C-MAP associated with the TXOP to be allocated. As an example, as illustrated in FIG. 9, the TXOP allocation frame may include information indicating that the TXOP allocation is for a C-SR operation.

[0172] A TXOP owner may terminate TXOP sharing if it does not receive a response (e.g., a response frame or / and a CTS frame, etc.) from an AP(s) participating in C-MAP (e.g., C-SR in FIG. 9) operation for a certain period of time.

[0173] For example, a TXOP owner may transmit a TXOP allocation frame to at least one AP and terminate TXOP sharing if no response to the TXOP allocation frame is received for a certain period of time (e.g., SIFS or PIFS). Here, at least one AP may be an AP(s) that participates / supports the C-MAP operation that transmitted the TXOP allocation frame (e.g., the C-MAP operation indicated by the schedule announcement frame).

[0174] For example, as illustrated in FIG. 9, if the TXOP owner participates in the C-SR operation and is a coordinating AP of the C-SR, the coordinated AP(s) may transmit information about their intention to participate in the C-SR to the TXOP owner before the TXOP allocation frame is transmitted and a certain amount of time has elapsed.

[0175] For example, if a TXOP owner participates in a C-SR operation and is a cooperative AP of the C-SR, other APs (e.g., other cooperative AP(s)) can transmit their intention to participate in the C-SR to the TXOP owner within a certain period of time after the TXOP allocation frame is transmitted. Then, the TXOP owner can transmit information about the AP(s) that have expressed their intention to participate in the C-SR operation to the cooperating APs through an additional frame. The additional frame may be a new frame for transmitting information about the AP(s) that have expressed their intention to participate in the C-SR operation, or may be an existing frame. The C-SR operation of FIG. 9 may be composed of a C-SR setup operation and a C-SR transmission section.

[0176] As an example of the present disclosure, a C-SR setup operation may be performed as illustrated in FIG. 10. Specifically, a TXOP-coordinated AP (e.g., a TXOP owner, etc.) may transmit a request frame for a C-SR invitation to at least one AP. Here, the at least one AP may include TXOP-coordinated AP(s) belonging to a C-SR set ID included in a schedule announcement frame or / and a TXOP allocation frame, or / and candidate TXOP-coordinated AP(s) established based on OBSS measurements.

[0177] Additionally or alternatively, the request frame may include identification information about the TXOP coordinating AP and / or the coordinated AP(s).

[0178] As illustrated in FIG. 10, the TXOP candidate AP(s) that received a request frame for a C-SR invitation from a TXOP cooperating AP may transmit a response frame to the TXOP cooperating AP, and the response frame may include information indicating participation in the C-SR operation.

[0179] For example, the request frame may include information indicating that a TXOP is shared with AP 2 in a C-SR operation and / or information about the C-SR operation. The response frame may include information about the C-SR operation, etc.

[0180] For example, the request frame and / or the response frame may include parameters to be used for the C-SR operation (e.g., minimum transmit power, maximum transmit power, MCS level, allocated TXOP interval, timeout value (e.g., value of time interval when C-SR transmission does not occur), etc.). For example, the request frame may include parameters to be used for the C-SR operation, and the response frame may include information indicating acceptance or rejection of the parameters to be used for the C-SR operation. Additionally or alternatively, the response frame may include information for suggesting parameters to be used for the (preferred) C-SR operation.

[0181] As an example of the present disclosure, assume that a TXOP-cooperating AP (e.g., AP 2) transmits a response frame to a TXOP-cooperating AP (e.g., AP 1) indicating that it participates in the C-SR operation. The TXOP-cooperating AP may transmit a trigger frame or / and a C-SR confirmation frame to the TXOP-cooperating AP for triggering the C-SR operation.

[0182] For example, as illustrated in FIG. 11, a TXOP-cooperating AP may transmit a DL PPDU with a transmission power (e.g., a transmission power related to a parameter to be used for the C-SR operation) applied to the STA(s) of AP 1. As another example, as illustrated in FIG. 12, a TXOP-cooperating AP may transmit a trigger frame containing a transmission power level required for UL TB PPDU transmission by the STA(s) to the STA(s) of AP 1.

[0183] For example, as illustrated in FIG. 11, the TXOP-coordinated AP(s) may transmit a DL PPDU with the received transmission power applied to the STA(s) of AP 2 via a confirmation frame. Additionally or alternatively, the TXOP-coordinated AP(s) may transmit a trigger frame containing transmission power level information required for UL TB PPDU transmission to the STA(s) of AP 2.

[0184] For example, as illustrated in FIG. 11, BAs for DL ​​PPDU transmissions transmitted by TXOP-cooperating APs and / or TXOP-cooperated AP(s) may be transmitted by STA(s). As another example, as illustrated in FIG. 12, each STA(s) that has received a trigger frame may transmit a UL TB PPDU to the TXOP-cooperating AP(s) and / or TXOP-cooperated AP(s).

[0185] As an example of the present disclosure, when a TXOP duration allocated by a TXOP owner expires, the TXOP-related usage rights shared with the TXOP shared AP may be reclaimed back to the TXOP owner.

[0186] For example, as illustrated in FIGS. 11 and 12, when the TXOP usage right is returned to the TXOP owner before the TXOP interval allocated from the TXOP owner expires, the TXOP cooperating AP can notify the TXOP of the return of the remaining TXOP interval by transmitting a termination frame to the TXOP owner. The termination frame can be transmitted via a basic frame (e.g., a CF-end frame) or defined in a new frame format.

[0187] As illustrated in FIGS. 9 to 12, when the TXOP owner and the TXOP cooperating AP are the same, the TXOP cooperating AP can notify the end of TXOP sharing to the TXOP cooperating AP(s) participating in the C-SR operation through a basic frame (e.g., a CTS-to-Self frame) or a new frame.

[0188] However, this is only one embodiment, and the termination frame transmission operation (transmitted by the TXOP owner) may be omitted.

[0189] Example 2

[0190] Embodiment 2 relates to a method in which a TXOP owner participates in C-SR operations (e.g., C-SR-based uplink transmission) with a TXOP-coordinated AP. Embodiment 2 relates to an example in which the TXOP owner applies C-TDMA and C-SR methods during the TXOP, but is not limited thereto. In the description according to Embodiment 2, each of the C-TDMA and C-SR methods may be replaced with a different type of C-MAP method.

[0191] As an example of the present disclosure, as illustrated in FIG. 13, AP 1, which is a TXOP owner, can transmit a schedule announcement frame in a broadcast manner. The configuration of the schedule announcement frame may be identical to the configuration of the schedule announcement frame described in Example 1.

[0192] Thereafter, AP 1 may transmit a TXOP allocation frame to AP(s) that support / participate in the C-MAP operation (e.g., C-SR operation) indicated by the schedule announcement frame. For example, a set ID corresponding to the corresponding AP(s) may be included in the TXOP allocation frame.

[0193] For example, the TXOP allocation frame may include identification information of an AP that will operate as a cooperating AP (e.g., AP 2) in C-SR operation and / or identification information of an AP that will operate as a cooperating AP (e.g., AP 1).

[0194] As an example of the present disclosure, as illustrated in FIG. 14, a TXOP-cooperating AP (e.g., AP 2) may transmit a request frame to a TXOP-cooperating AP (e.g., AP 1). The request frame may include information for inviting to a C-SR operation (e.g., identification information of an AP to be invited to the C-SR operation, etc.). The operations of the TXOP-cooperating AP and the TXOP-cooperated AP may be the same as the operations described in Embodiment 1 (e.g., the operations described with reference to FIG. 10). That is, a TXOP owner may operate as a TXOP-cooperating AP, and a TXOP-shared AP may operate as a TXOP-cooperating AP.

[0195] The operations according to FIGS. 15 and 16 may also correspond to the operations described in Embodiment 1 (e.g., the operations described with reference to FIGS. 11 and 12). The termination frame may also be transmitted by a TXOP-shared AP that operates as a TXOP-cooperating AP. For example, a TXOP-cooperating AP may transmit the termination frame as a TXOP owner.

[0196] Example 3

[0197] Embodiment 3 relates to a case where the TXOP owner does not participate in the C-SR operation. Embodiment 3 relates to an example in which the C-TDMA method and the C-SR method are applied during the TXOP, but is not limited thereto. In the description according to Embodiment 3, each of the C-TDMA method and the C-SR method may be replaced with a different type of C-MAP method.

[0198] As an example of the present disclosure, as illustrated in FIG. 17, AP 1, which is a TXOP owner, can transmit a schedule announcement frame in a broadcast manner. The configuration of the schedule announcement frame may be identical to the configuration of the schedule announcement frame described in Example 1.

[0199] Thereafter, AP 1 may transmit a TXOP allocation frame to AP(s) that support / participate in the C-MAP operation (e.g., C-SR operation) indicated by the schedule announcement frame. For example, a set ID corresponding to the corresponding AP(s) may be included in the TXOP allocation frame.

[0200] For example, the TXOP allocation frame may include identification information of an AP that will operate as a cooperating AP (e.g., AP 2) in the C-SR operation and / or identification information of an AP that will operate as a cooperating AP (e.g., AP 3). That is, AP 1, which is the TXOP owner, may transmit a TXOP allocation frame that includes information indicating that it will not perform the C-SR operation.

[0201] As an example of the present disclosure, as illustrated in FIG. 18, a TXOP-cooperating AP (e.g., AP 2) may transmit a request frame to a TXOP-cooperating AP (e.g., AP 3). The request frame may include information for inviting to a C-SR operation (e.g., identification information of an AP to invite to the C-SR operation, etc.). The operations of the TXOP-cooperating AP and the TXOP-cooperated AP may be the same as the operations described in Embodiment 2 (e.g., the operations described with reference to FIG. 10). That is, a TXOP owner may operate as a TXOP-cooperating AP, and a TXOP-shared AP may operate as a TXOP-cooperating AP.

[0202] The operations according to FIGS. 19 and 20 may also correspond to the operations described in Embodiment 1 (e.g., the operations described with reference to FIGS. 11 and 12). The termination frame may also be transmitted by a TXOP-shared AP that operates as a TXOP-cooperating AP. For example, the TXOP-cooperating AP may transmit the termination frame to the TXOP owner. That is, as illustrated in FIGS. 19 and 20, the C-SR operation may be performed between TXOP-shared APs that are not TXOP owners.

[0203] Example 4

[0204] Example 4 relates to a procedure for a TXOP owner to perform a C-MAP operation.

[0205] As illustrated in FIG. 21, AP 1, the TXOP owner, can transmit a schedule announcement frame in a broadcast manner. The configuration of the schedule announcement frame may be identical to the configuration of the schedule announcement frame described in Example 1.

[0206] For example, the schedule announcement frame may include information indicating that a TXOP will be shared by a specific type of C-MAP operation. Additionally, the schedule announcement frame may include information about at least one AP(s) invited to participate in the specific type of C-MAP operation and / or information indicating that the TXOP will be shared with another C-MAP operation.

[0207] STA(s) of AP 1 and / or AP 2 (e.g., TXOP shared AP) may transmit a response frame (e.g., a CTS frame, a CTS-to-Self frame, etc.) to AP 1 in response to the schedule announcement frame. The response frame may include information about whether it can participate in the C-MAP operation initiated by the TXOP owner (or / and information related to its willingness to participate in the C-MAP operation).

[0208] For example, if STA(s) of AP 1 and / or AP 2 do not transmit a response frame within a certain period of time (e.g., SIFS or PIFS) after the schedule announcement frame is transmitted, this may mean that STA(s) of AP 1 and / or AP 2 do not participate in the C-MAP operation.

[0209] After receiving a willingness to participate in C-MAP operation from an AP(s) (e.g., AP 2, etc.), the TXOP owner may transmit a confirmation frame to the AP(s) regarding the C-MAP operation and / or related decisions and / or parameters. The confirmation frame may be an existing frame, a variant of an existing frame, or a new type of frame.

[0210] For example, the confirmation frame may include information about the AP(s) that will participate in the C-MAP operation and / or information related to the C-MAP operation (e.g., transmission order and / or start time of the C-MAP, transmission parameters for the C-MAP operation, etc.). Here, the parameters applied to the C-MAP operation may include at least one of the transmission power, TXOP interval, or modulation and coding scheme (MCS) level to be applied to the C-MAP operation.

[0211] The TXOP owner can classify the AP(s) that have transmitted their intent to participate into sets. That is, the TXOP can distinguish the AP(s) that have notified their intent to participate using the set ID element, or separately manage and classify the identification information of each AP(s). For example, if AP 1 and AP 3 are identified as participating in the C-MAP operation, the TXOP owner can manage the AP(s) participating in the C-MAP operation as "Set ID 1 = {AP 1, AP 3}", or separately store the identification information of AP 1 and AP 3.

[0212] For example, the identification information of an AP or individual AP included in a set ID element may consist of basic identification information (e.g., MAC ID) or newly defined identification information (e.g., "partial MAC ID and BSS color").

[0213] If no participation intent is received from the AP(s), the confirmation frame may include cancellation information for the C-MAP operation. That is, if no information to participate in the C-MAP operation is received from all AP(s), the TXOP owner may transmit a confirmation frame including cancellation information for the C-MAP operation to the AP(s) and / or the TXOP owner's STA(s). At this time, the TXOP owner may use the remaining TXOP interval for intra-BSS STA(s) (e.g., STA(s) associated with the TXOP owner's BSS).

[0214] As another example of the present disclosure, if no participation intent is received from the AP(s), the TXOP owner may not transmit a confirmation frame. In this case, the TXOP owner may exchange frames with the STA(s) within the TXOP owner's BSS without performing the C-MAP operation.

[0215] Additionally or alternatively, if no intent to participate is received from the AP(s), the TXOP owner may perform other C-MAP operations by transmitting additional schedule announcement frames.

[0216] FIG. 22 is a flowchart illustrating an operation performed by a first AP according to one embodiment of the present disclosure.

[0217] The first AP may transmit a schedule announcement frame to at least one AP (S2210). In describing the present disclosure, the name of the schedule announcement frame (e.g., "first frame") may be changed. For example, the schedule announcement frame may be included in a multi-user (MU) ready-to-send (RTS) transmission opportunity sharing (TXS) frame, but is not limited thereto.

[0218] For example, the schedule announcement frame may include information related to at least one type of coordinated multi-AP (C-MAP) operation supported by the first AP within a first transmission opportunity (TXOP), wherein the first AP may be the owner (or holder) of the first TXOP.

[0219] At least one type of C-MAP operation may include at least one of a C-TDMA (time division multiple access) operation, a C-SR (spatial reuse) operation, a C-RTWT (restricted target wake time) operation, a C-OFDMA (orthogonal frequency division multiple access) operation, or a C-BF (beamforming) operation.

[0220] For example, the schedule notification frame may include a bitmap related to at least one type of C-MAP operation. The bitmap may include bits corresponding to at least one type of C-MAP operation. For example, if the first AP supports the C-SR operation, the bit value corresponding to the C-SR operation in the bitmap may be set to 1.

[0221] For example, the first AP may transmit a schedule announcement frame in a broadcast manner. For example, the schedule announcement frame may be transmitted to at least one STA and / or at least one AP (e.g., an OBSS AP) within the BSS of the first AP.

[0222] For example, the schedule announcement frame may be transmitted from the first AP to at least one AP within the first TXOP, or may be transmitted from the first AP to at least one AP during a negotiation phase prior to the first TXOP (e.g., a negotiation phase for C-MAP operation).

[0223] Additionally or alternatively, the schedule announcement frame may include information about at least one AP that will share the first TXOP via at least one type of C-MAP operation. At least one AP may support at least one type of C-MAP, and the first AP may obtain information in advance about the types of C-MAP supported by each of the at least one AP (e.g., through a negotiation phase).

[0224] For example, the schedule announcement frame may include set ID (identification) information for at least one AP. For example, if the APs supporting C-SR are the second AP and the third AP, the schedule announcement frame may include the set IDs to which the second AP and the third AP belong.

[0225] The first AP can receive a first response frame corresponding to the schedule notification frame from at least one of the second APs (S2220).

[0226] For example, the first response frame may be, but is not limited to, a CTS frame and / or a CTS-to-Self frame. The first response frame may include at least one of information regarding whether to participate in at least one type of C-MAP operation, information regarding whether to participate in at least one type of C-MAP operation, or identification information of the second AP. Assume that the second AP transmits the first response frame to the first AP, which includes information indicating that the second AP participates in at least one type of C-MAP operation.

[0227] The first AP can transmit a TXOP assignment frame (or a second frame) to the second AP, which includes information about a coordinating AP and a coordinated AP for the first type of C-MAP operation among at least one type of C-MAP operation. For example, the TXOP assignment frame can set each of a coordinating AP and a coordinated AP for the first type of C-MAP operation. That is, the first AP, which is the TXOP owner, can operate as a coordinating AP or a coordinated AP, or can not operate as a coordinating AP or a coordinated AP.

[0228] For example, based on whether the first AP is a cooperating AP or a non-cooperating AP, a TXOP allocation frame may be transmitted to at least one of the second AP and the third AP. In this case, the TXOP allocation frame may include information indicating that each of the second AP and the third AP is a cooperating AP or a non-cooperating AP. The second AP and the third AP may perform a first type of C-MAP operation within the first TXOP.

[0229] For example, sharing of a first TXOP associated with a first type of C-MAP operation may be terminated by the first AP based on the second response frame for the TXOP allocation frame not being transmitted from the second AP to the first AP within a certain period of time (e.g., SIFS or PIFS) after the TXOP allocation frame is transmitted.

[0230] As an example of the present disclosure, a first AP may transmit a request frame to a second AP before transmitting a trigger frame. That is, the first AP may transmit a request frame to the second AP to request that the first type of C-MAP operation be performed within the first TXOP. The second AP may transmit a third response frame corresponding to the request frame to the first AP. The first AP may transmit a trigger frame to the second AP that has transmitted the third response frame acknowledging the request frame.

[0231] The first AP can transmit a trigger frame for a first type of C-MAP operation among at least one type of C-MAP operation to the second AP (S2230).

[0232] For example, the trigger frame may include information about a time when a first type of C-MAP operation starts or at least one of parameters applicable to the first type of C-MAP operation. The parameters applicable to the first type of C-MAP operation may include at least one of a transmit power, a TXOP interval, or a modulation and coding scheme (MCS) level applicable to the first type of C-MAP operation.

[0233] As an example of the present disclosure, if it is determined that the first AP and the second AP perform the first type of C-MAP operation, the first AP and the second AP may perform the first type of C-MAP operation within the first TXOP. For example, the first AP and the second AP may perform the first type of C-MAP operation within the first TXOP based on a trigger frame.

[0234] For example, a first AP may perform a C-MAP operation of the first type with at least one STA within the BSS of the first AP. At this time, a second AP may also perform a C-MAP operation of the first type with at least one STA within the BSS of the second AP. In other words, the first AP and the second AP may share a first TXOP to perform a C-MAP operation of the first type.

[0235] For example, the right to use the first TXOP may be returned to the first AP based on the expiration of the TXOP interval applicable to the first type of C-MAP operation (e.g., the TXOP interval configured to perform the first type of C-MAP operation) or the transmission of a termination frame by the first AP to the second AP.

[0236] The method performed by the first AP described in the example of FIG. 22 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 transmit a schedule announcement frame to at least one AP via one or more transceivers (106). The one or more processors (102) may receive a first response frame corresponding to the schedule announcement frame from a second AP among the at least one AP via one or more transceivers (106). The one or more processors (102) may transmit a trigger frame for a first type of C-MAP operation among at least one type of C-MAP operation to the second AP via one or more transceivers (106).

[0237] The above memory (104) can store instructions for performing the method described in the example of FIG. 22 when executed by one or more processors (102).

[0238] FIG. 23 is a flowchart illustrating an operation performed by a second AP according to one embodiment of the present disclosure.

[0239] The second AP can receive a schedule notification frame from the first AP (S2310).

[0240] Here, the first AP may be an AP of the first BSS, and the second AP may be an AP of the second BSS. That is, the second AP may be an OBSS AP based on the first AP. The second AP may transmit information about the type of C-MAP operation it supports to the first AP (during the negotiation phase). The second AP may decode / identify the identification information of the AP with which it will share the first TXOP, the type of C-MAP operation to be performed within the first TXOP, etc., through the schedule announcement frame.

[0241] The second AP may transmit a first response frame corresponding to the schedule notification frame to the first AP (S2320). That is, the second AP may transmit information to the first AP via the first response frame regarding whether to participate in at least one type of C-MAP operation (e.g., the first type of C-MAP operation) within the first TXOP.

[0242] The second AP can receive a trigger frame for a first type of C-MAP operation among at least one type of C-MAP operation from the first AP (S2330).

[0243] The second AP may perform a first type of C-MAP operation based on a trigger frame within the first TXOP. For example, the second AP may perform the first type of C-MAP operation with at least one STA within the BSS of the second AP.

[0244] The method performed by the second AP described in the example of FIG. 23 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. 10 may receive a schedule announcement frame from the first AP through one or more transceivers (206). The one or more processors (202) may transmit a first response frame corresponding to the schedule announcement frame to the first AP through one or more transceivers (206). The one or more processors (202) may receive a trigger frame for a first type of C-MAP operation among at least one type of C-MAP operation from the first AP through one or more transceivers (206).

[0245] Furthermore, one or more memories (204) of the second device (200) may store instructions for performing the method described in the example of FIG. 23 when executed by one or more processors (202).

[0246] 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.

[0247] 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.

[0248] 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.

[0249] 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 step of transmitting a schedule announcement frame by a first access point (AP) to at least one AP, wherein the schedule announcement frame includes information related to at least one type of coordinated multi-AP (C-MAP) operation supported by the first AP within a first transmission opportunity (TXOP); A step of receiving a first response frame corresponding to the schedule notification frame from a second AP among the at least one AP by the first AP; and A step of transmitting a trigger frame for a first type of C-MAP operation among at least one type of C-MAP operation by the first AP to the second AP, A method wherein the first AP is the owner of the first TXOP.

2. In paragraph 1, A method wherein the at least one type of C-MAP operation comprises at least one of a C-TDMA (time division multiple access) operation, a C-SR (spatial reuse) operation, a C-RTWT (restricted target wake time) operation, a C-OFDMA (orthogonal frequency division multiple access) operation, or a C-BF (beamforming) operation.

3. In paragraph 1, A method wherein the schedule notification frame includes a bitmap associated with at least one type of C-MAP operation.

4. In paragraph 1, A method wherein the schedule notification frame is transmitted to the at least one AP within the first TXOP or transmitted to the at least one AP in a negotiation stage prior to the first TXOP.

5. In paragraph 1, A method wherein the trigger frame includes at least one of information about a time at which the first type of C-MAP operation starts or a parameter applied to the first type of C-MAP operation.

6. In paragraph 1, The above schedule notification frame is included in a multi-user (MU) ready-to-send (RTS) transmission opportunity sharing (TXS) frame.

7. In paragraph 1, A method wherein the above schedule notification frame includes set ID (identification) information for at least one AP.

8. In paragraph 5, A method in which a TXOP allocation frame containing information about a coordinating AP and a coordinated AP of the first type of C-MAP operation is transmitted from the first AP to the second AP.

9. In paragraph 8, Based on the first AP being not the cooperating AP or the cooperating AP, the TXOP allocation frame is transmitted to a third AP among the at least one AP, A method wherein the first type of C-MAP operation is performed within the first TXOP by the second AP and the third AP.

10. In paragraph 8, A method wherein the first TXOP sharing associated with the first type of C-MAP operation is terminated by the first AP based on the second response frame for the TXOP allocation frame not being transmitted from the second AP to the first AP within a certain time after the TXOP allocation frame is transmitted.

11. In paragraph 10, The trigger frame is transmitted to the second AP that transmitted the second response frame, A method wherein the parameters applied to the first type of C-MAP operation include at least one of a transmission power, a TXOP interval, or a modulation coding scheme (MCS) level to be applied to the first type of C-MAP operation.

12. In paragraph 11, A method in which the right to use the first TXOP is returned to the first AP based on the expiration of the TXOP period applicable to the first type of C-MAP operation or the transmission of a termination frame by the first AP to the second AP.

13. In the first access point (AP), 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 schedule announcement frame to at least one AP via the one or more transceivers, the schedule announcement frame including information related to at least one type of coordinated multi-AP (C-MAP) operation supported by the first AP within a first transmission opportunity (TXOP); Receiving a first response frame corresponding to the above schedule notification frame from a second AP among the at least one AP through the one or more transceivers; and is set to transmit a trigger frame for a first type of C-MAP operation among at least one type of C-MAP operation to the second AP; The above first AP is the first AP, which is the owner of the first TXOP.

14. A step of receiving a schedule announcement frame from a first access point (AP) by a second access point (AP), wherein the schedule announcement frame includes information related to at least one type of coordinated multi-AP (C-MAP) operation supported by the first AP within a first transmission opportunity (TXOP); A step of transmitting a first response frame corresponding to the schedule notification frame to the first AP by the second AP; and A step of receiving, by the second AP, a trigger frame for a first type of C-MAP operation among the at least one type of C-MAP operation from the first AP, A method wherein the first AP is the owner of the first TXOP.

15. In the second access point (AP), the second 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: Receiving a schedule announcement frame from a first AP via the one or more transceivers, the schedule announcement frame including information related to at least one type of coordinated multi-AP (C-MAP) operation supported by the first AP within a first transmission opportunity (TXOP); Transmitting a first response frame corresponding to the above schedule notification frame to the first AP through the one or more transceivers; and A trigger frame for a first type of C-MAP operation among at least one type of C-MAP operation is set to be received from the first AP through the one or more transceivers, The above first AP is the second AP, which is the owner of the first TXOP.

16. In a processing device configured to control a station (STA) in a wireless local area network (WLAN) system, 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 that, when executed by said one or more processors, perform a method according to any one of claims 1 to 12.

17. 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 12.

Images