Method and device for coordinated beamforming sounding in wireless LAN system

Abstract

A method and a device for coordinated beamforming sounding in a wireless LAN system are disclosed. The method according to one embodiment of the present disclosure may comprise steps in which an STA: transmits a first frame to a first AP; and receives, from the first AP, a second frame in response to the first frame. The first frame and / or the second frame can include information about a capability related to Co-BF sounding.

Description

Method and device for cooperative beamforming sounding in a wireless LAN system

[0001] The present disclosure relates to a method and apparatus for coordinated beamforming (Co-BF) sounding in a Wireless Local Area Network (WLAN) system.

[0002] New technologies have been introduced for wireless LANs (WLANs) to improve transmission rates, increase bandwidth, enhance reliability, reduce errors, and reduce latency. Among wireless LAN technologies, the IEEE (Institute of Electrical and Electronics Engineers) 802.11 series of standards can be referred to as Wi-Fi. For example, technologies recently introduced to wireless LANs 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 an improved wireless communication environment, advanced technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for Multiple Input Multiple Output (MIMO) supporting increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, as well as technologies for multiple access points (AP) coordination, are being researched. In particular, various technologies are being studied to support traffic with low latency or real-time characteristics. Furthermore, new technologies to support ultra-high reliability (UHR), including improvements or extensions of EHT technology, are being discussed.

[0004] The technical problem of the present disclosure is to provide a method and apparatus for sounding a null data packet (NDP) for coordinated beamforming (Co-BF).

[0005] The technical problem of the present disclosure is to provide a method and apparatus for exchanging capabilities related to null data packet (NDP) sounding for Co-BF.

[0006] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below.

[0007] A method according to one aspect of the present disclosure may include: transmitting a first frame to a first access point (AP) by a station (STA); and receiving a second frame from the first AP in response to the first frame by the STA. The first frame and / or the second frame may include information regarding a capability related to coordinated beamforming (Co-BF) sounding.

[0008] A method according to a further aspect of the present disclosure may include: receiving a first frame from a station (STA) by a first access point (AP); and transmitting a second frame to the STA by the first AP in response to the first frame. The second frame may include information regarding the capability of the first AP to coordinated beamforming (Co-BF) sounding.

[0009] According to the present disclosure, channel information for one or more OBSS STAs is obtained through Co-BF NDP sounding, allowing multiple APs to smoothly perform Co-BF.

[0010] In addition, according to the present disclosure, by exchanging capabilities related to Co-BF NDP sounding in advance, it is possible to clearly determine whether to participate in a Co-BF transmission operation.

[0011] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

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

[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 drawing showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

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

[0016] FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied.

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

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

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

[0020] FIG. 8 shows an exemplary format of an NDP notice frame to which the present disclosure may be applied.

[0021] FIG. 9 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0022] FIG. 10 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0023] FIG. 11 is a drawing illustrating a PPDU format according to one embodiment of the present disclosure.

[0024] FIG. 12 illustrates the operation of an STA device for a method for cooperative beamforming sounding according to one embodiment of the present disclosure.

[0025] FIG. 13 illustrates the operation of an AP device for a method for cooperative beamforming sounding according to one embodiment of the present disclosure.

[0026] FIG. 14 illustrates a Co-BF sounding procedure according to one embodiment of the present disclosure.

[0027] FIG. 15 illustrates the operation of an STA device for a method for cooperative beamforming sounding according to one embodiment of the present disclosure.

[0028] FIG. 16 illustrates the operation of an AP device for a method for cooperative beamforming sounding according to one embodiment of the present disclosure.

[0029] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below, together with the accompanying drawings, is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure may be practiced. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the art will know that the present disclosure may be practiced without such specific details.

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

[0031] In the present disclosure, when a component is described as being “connected,” “combined,” or “joined” with another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, in the present disclosure, the terms “comprising” or “having” specify the presence of the mentioned features, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, actions, elements, components, and / or groups thereof.

[0032] In the present disclosure, terms such as "first," "second," etc. are used solely for the purpose of distinguishing one component from another and are not used to limit the components, nor do they limit the order or importance of the components unless specifically stated otherwise. Accordingly, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and likewise, a second component in one embodiment may be referred to as a first component in another embodiment.

[0033] The terms used in this disclosure are for the description of specific embodiments and are not intended to limit the claims. As used in the description of embodiments and in the appended claims, the singular form is intended to include the plural form unless the context clearly indicates otherwise. The term "and / or" as used in this disclosure may refer to any one of the related enumerated items, or refers to and includes any and all possible combinations of two or more of them. Additionally, the " / " between words in this disclosure has the same meaning as "and / or" unless otherwise noted.

[0034] The embodiments of the present disclosure may be applied to various wireless communication systems. For example, the embodiments of the present disclosure may be applied to wireless LAN systems. For example, the embodiments of the present disclosure may be applied to wireless LANs based on IEEE 802.11a / g / n / ac / ax / be standards. Furthermore, the embodiments of the present disclosure may be applied to wireless LANs based on newly proposed IEEE 802.11bn (or UHR) standards. Additionally, the embodiments of the present disclosure may be applied to wireless LANs based on next-generation standards following IEEE 802.11bn. Furthermore, the embodiments of the present disclosure may be applied to cellular wireless communication systems. For example, they may be applied to cellular wireless communication systems based on LTE (Long Term Evolution) series technologies and 5G NR (New Radio) series technologies of 3GPP (3rd Generation Partnership Project) standards.

[0035] The following describes the technical features to which the examples of the present disclosure may be applied.

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

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

[0038] The device (100, 200) exemplified in FIG. 1 may be referred to as a station (STA). For example, the device (100, 200) exemplified in FIG. 1 may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, or a receiving STA. For example, the STA (110, 200) may perform the role of an access point (AP) or a non-AP. That is, in the present disclosure, the STA (110, 200) may perform the functions of an AP and / or a non-AP. If the STA (110, 200) performs the AP function, it may simply be referred to as an AP, and if the STA (110, 200) performs the non-AP function, it may simply be referred to as a STA. Additionally, in the present disclosure, the AP may also be indicated as an AP STA.

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

[0040] In addition, the first device (100) and the second device (200) may additionally support various communication standards other than wireless LAN technology (e.g., 3GPP LTE series, 5G NR series standards, etc.). In addition, the device of the present disclosure may be implemented as various devices such as mobile phones, vehicles, personal computers, AR (Augmented Reality) equipment, VR (Virtual Reality) equipment, etc. Furthermore, the STA of the present specification may support various communication services such as voice calls, video calls, data communication, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).

[0041] The first device (100) includes one or more processors (102) and one or more memories (104), and may additionally include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memory (104) and / or transceivers (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (102) may process information within the memory (104) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through the transceiver (106) and then store information obtained from the signal processing of the second information / signal in the memory (104). Memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, memory (104) may store software code including instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this disclosure. Here, the processor (102) and memory (104) may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals through one or more antennas (108). The transceiver (106) may include a transmitter and / or receiver. The transceiver (106) may be combined with an RF (Radio Frequency) unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0042] The second device (200) includes one or more processors (202) and one or more memories (204), and may additionally include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memory (204) and / or transceivers (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this disclosure. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement 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 through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be used in combination with an RF unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0043] Hereinafter, 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 Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this 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 flowcharts of operation disclosed in this disclosure. One or more processors (102, 202) may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this disclosure and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., a baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this disclosure.

[0044] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or 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 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. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure may be included in 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 sequences disclosed in this disclosure may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0045] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0046] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of the present disclosure to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., disclosed in the present disclosure from one or more other devices. For example, one or more transceivers (106, 206) may be connected to one or more processors (102, 202) and may transmit and receive wireless signals. For example, one or more processors (102, 202) may 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 connected 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, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure through one or more antennas (108, 208). In this disclosure, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0047] For example, one of the STAs (100, 200) may perform the intended operation of an AP, and the other of the STAs (100, 200) may perform the intended operation of a non-AP STA. For example, the transceiver (106, 206) of FIG. 1 may perform the operation of transmitting and receiving signals (e.g., packets or PPDU (Physical Layer Protocol Data Unit) according to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). Additionally, the operation of generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals by various STAs in the present disclosure may be performed by the processor (102, 202) of FIG. 1. For example, an example of an operation to generate a transmission and reception signal or to perform data processing or operations in advance for a transmission and reception signal may include: 1) an operation to determine / acquire / configure / operate / decode / encode bit information of fields (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in the PPDU; 2) an operation to determine / configure / acquire time resources or frequency resources (e.g., subcarrier resources) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 3) an operation to determine / configure / acquire specific sequences (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 4) power control operations and / or power saving operations applied to the STA; and 5) operations related to determining / acquiring / configuring / operating / decoding / encoding of an ACK signal. In addition, various information (e.g., information related to fields, subfields, control fields, parameters, power, etc.) used by various STAs for determining / acquiring / configuring / calculating / decoding / encoding transmission and reception signals in the following example can be stored in the memory (104, 204) of FIG. 1.

[0048] In the following, the 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 the AP STA, and the receiver may be part of the non-AP STA. The 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 the non-AP STA, and the receiver may be part of the AP STA.

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

[0050] The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports STA mobility transparent to the upper layer can be provided. A Basic Service Set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 exemplarily illustrates 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). In Figure 2, the ellipse representing the BSS can also be understood as representing the coverage area where the STAs included in the corresponding BSS maintain communication. This area can be referred to as a Basic Service Area (BSA). If a STA moves outside the BSA, it becomes unable to communicate directly with other STAs within that BSA.

[0051] Excluding the DS illustrated in Fig. 2, the most basic type of BSS in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For instance, assuming other components are omitted, a BSS1 composed of only STA1 and STA2, or a BSS2 composed of only STA3 and STA4, can each be considered a representative example of an IBSS. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, this type of wireless LAN is not configured through pre-planning but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. In other words, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and since connections to distributed systems (DS) are not allowed, they form a self-contained network.

[0052] The membership of an STA in a BSS can be dynamically changed by the STA being turned on or off, or by the STA entering or leaving the BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, an STA must be associated with the BSS. This association can be configured dynamically and may include the use of a Distribution System Service (DSS).

[0053] In a wireless LAN, the direct STA-to-STA distance may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in others, communication between STAs over longer distances may be required. To support extended coverage, a distributed system (DS) may be configured.

[0054] DS refers to a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component in an extended form of a network composed of multiple BSSs. DS is a logical concept and can be specified by the characteristics of the Distributed System Medium (DSM). In this regard, the Wireless Medium (WM) and the DSM can be logically distinguished. Each logical medium is used for a different purpose and is utilized by different components. These media are not limited to being identical or different. The flexibility of the wireless LAN structure (DS structure or other network structure) can be explained by the fact that multiple media are logically distinct in this way. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be specified independently by the physical characteristics of each implementation.

[0055] DS can support mobile devices by providing seamless integration of multiple BSSs and providing logical services necessary for handling addresses to destinations. Additionally, DS may include a component called a portal that acts as a bridge for connecting the wireless LAN with another network (e.g., IEEE 802.X).

[0056] An AP refers to an entity that enables access to the DS via the WM for combined non-AP STAs and also possesses the functionality of an STA. Data movement between the BSS and the DS can be performed through the AP. For example, STA2 and STA3 shown in FIG. 2 possess the functionality of an STA and provide the ability for combined non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs fundamentally correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM and the address used by the AP for communication on the DSM do not necessarily have to be the same. A BSS composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0057] Data transmitted from one of the STA(s) coupled to the AP to the STA address of the AP can always be received at an uncontrolled port and processed by an IEEE 802.1X port access entity. Additionally, if the controlled port is authenticated, the transmitted data (or frame) can be forwarded to the DS.

[0058] In addition to the structure of the aforementioned DS, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0059] An ESS refers to a network of arbitrary size and complexity composed of DSs and BSSs. An ESS can correspond to a set of BSSs connected to a single DS. However, an ESS does not contain a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs included in 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 included in a single ESS can have the same Service Set Identification (SSID). The SSID is distinct from the BSSID, which is the identifier for the BSS.

[0060] In wireless LAN systems, no assumptions are made regarding the relative physical locations of BSSs, and all of the following forms are possible. BSSs may partially overlap, which is a form commonly used to provide continuous coverage. Additionally, BSSs may not be physically connected, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs may be located in the same physical location, which can be used to provide redundancy. Also, one (or more) IBSS or ESS networks may physically exist in the same space as one (or more) ESS networks. This may apply to ESS network forms such as when an ad-hoc network operates at a location where an ESS network exists, when wireless networks that physically overlap are configured by different organizations, or when two or more different access and security policies are required at the same location.

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

[0062] In order 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 go through authentication procedures for security. The link setup process can also be referred to as the session initiation process or the session setup process. Additionally, the processes of discovery, authentication, association, and security setup in the link setup process can be collectively referred to as the association process.

[0063] In step S310, the STA may perform a network discovery operation. The network discovery operation may include the STA's scanning operation. That is, in order for the STA to access a network, it must find a network it can join. Before joining a wireless network, the STA must identify a compatible network, and the process of identifying networks existing in a specific area is called scanning.

[0064] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, the STA performing the scanning moves between channels to search for nearby APs, transmits a probe request frame, and waits for a response. The responder transmits a probe response frame as a response to the probe request frame to the STA that transmitted the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame from the BSS of the channel being scanned. In a BSS, the AP becomes the responder because it transmits the beacon frame; however, in an IBSS, the responder is not constant because STAs within the IBSS take turns transmitting the beacon frame. 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 in the same way (i.e., transmit and receive probe request / response on channel 2).

[0065] Although not illustrated in FIG. 3, the scanning operation may be performed using a passive scanning method. In passive scanning, the STA performing the scanning waits for a beacon frame while switching between channels. A beacon frame is one of the management frames defined in IEEE 802.11, which is periodically transmitted to announce the presence of a wireless network and to allow the scanning STA to find the wireless network and join it. In a BSS, the AP performs the role of periodically transmitting beacon frames, and in an IBSS, the STAs within the IBSS take turns transmitting beacon frames. When the scanning STA receives a beacon frame, it stores the information about the BSS included in the beacon frame and records the beacon frame information in each channel while moving to another channel. The STA that receives the beacon frame stores the BSS-related information included in the received beacon frame and moves to the next channel, and can perform scanning in the next channel in the same way. When comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

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

[0067] The authentication process involves the STA sending an authentication request frame to the AP, and the AP sending an authentication response frame to the STA in response. The authentication frame used in the authentication request / response corresponds to a management frame.

[0068] The authentication frame may include information regarding the authentication algorithm number, authentication transaction sequence number, status code, challenge text, Robust Security Network (RSN), Finite Cyclic Group, etc. These are some examples of information that may be included in the authentication request / response frame, and they may be replaced with other information or additional information may be included.

[0069] The STA can send an authentication request frame to the AP. Based on the information contained in the received authentication request frame, the AP can determine whether to allow authentication for the STA. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0070] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the STA transmitting an association request frame to the AP, and in response, the AP transmitting an association response frame to the STA.

[0071] For example, the association request frame may include information regarding various capabilities, beacon listen interval, service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information regarding various capabilities, status code, Association ID (AID), supported rates, Enhanced Distributed Channel Access (EDCA) parameter set, Received Channel Power Indicator (RCPI), Received Signal to Noise Indicator (RSNI), mobility domain, timeout interval (e.g., association comeback time), overlapping BSS scan parameters, TIM broadcast response, Quality of Service (QoS) map, etc. These are some examples of information that may be included in a combined request / response frame, and may be replaced with other information or additional information may be included.

[0072] After the STA is successfully joined to the network, a security setup process can be performed in step S340. The security setup process in step S340 may be described as an authentication process through RSNA (Robust Security Network Association) requests / responses, and the authentication process in step S320 may be referred to as the first authentication process, and the security setup process in step S340 may simply be referred to as the authentication process.

[0073] The security setup process of step S340 may include, for example, a private key setup process through a 4-way handshake via an EAPOL (Extensible Authentication Protocol over LAN) frame. Additionally, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

[0074] FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied.

[0075] In wireless LAN systems, the basic access mechanism for MAC (Medium Access Control) is the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism is also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, and it basically employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA may perform Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time interval (e.g., DIFS (DCF Inter-Frame Space)) before starting transmission. If the sensing result determines that the medium is in an idle status, it starts transmitting a frame through that 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 wait by setting a delay period for medium access (e.g., a random backoff period) before attempting to transmit a frame. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

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

[0077] Referring to FIG. 4, the operation based on the random backoff period is described. When a medium in an occupied / busy state changes to an idle state, multiple STAs may attempt to transmit data (or frames). As a measure to minimize collisions, each STA may select a random backoff count and attempt transmission after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​in the range from 0 to CW. Here, CW is the Contention Window parameter value. The CW parameter is given an initial value of CWmin, but in the case of transmission failure (e.g., failure to receive an ACK for a transmitted frame), it may take a value twice that amount. When the CW parameter value becomes CWmax, data transmission may be attempted while maintaining the CWmax value until data transmission is successful; if data transmission is successful, it is reset to the CWmin value. The values ​​of CW, CWmin, and CWmax are 2 n It is desirable to set it to -1 (n=0, 1, 2, ...).

[0078] When the random backoff process begins, the STA continues to monitor the media while counting down the backoff slots according to the determined backoff count value. When the media is monitored as occupied, it stops the countdown and waits, and when the media becomes idle, it resumes the remaining countdown.

[0079] In the example of Fig. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 confirms that the medium is idle for DIFS and can immediately transmit the frame. The remaining STAs monitor whether the medium is occupied or busy and wait. Meanwhile, data to be transmitted may also arise from each of STA1, STA2, and STA5, and each STA can perform a countdown of the backoff slot according to a random backoff count value selected by each after waiting for DIFS when the medium is monitored to be idle. Assume the case where STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. That is, this exemplifies a case where, at the point when STA2 finishes the backoff count and starts transmitting the frame, the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1. STA1 and STA5 pause the countdown briefly and wait while STA2 occupies the medium. When STA2's possession ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the paused backoff count. That is, they can start transmitting a frame after counting down the remaining backoff slots corresponding to the remaining backoff time. Since STA5's remaining backoff time was shorter than STA1's, STA5 starts transmitting the frame. While STA2 is occupying the medium, data to be transmitted may also be generated by STA4. From STA4's perspective, when the medium becomes idle, it waits for DIFS, performs a countdown based on a random backoff count value selected by itself, and can start transmitting a frame. The example in Figure 4 illustrates a case where STA5's remaining backoff time happens to match STA4's random backoff count value; in this case, a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 receives an ACK, resulting in a failure to transmit data.In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. STA1 waits while the medium is occupied due to transmission by STA4 and STA5, and when the medium becomes idle, it waits for DIFS, and then can start transmitting frames after the remaining backoff time has passed.

[0080] As shown in the example in Fig. 4, a data frame is a frame used for transmitting data that is forwarded to an upper layer, and can be transmitted after a backoff performed after the elapsed time of DIFS from when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information that is not forwarded to an upper layer, and is transmitted after a backoff performed after the elapsed time of an IFS such as DIFS or PIFS (Point coordination function IFS). Subtypes of management frames include Beacon, Association request / response, re-association request / response, probe request / response, and authentication request / response. A control frame is a frame used to control access to the medium. Subtype frames of control frames include RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), NDP Announcement (null data packet announcement), and Trigger. If a control frame is not an acknowledgment frame of a previous frame, it is transmitted after a backoff performed after the elapsed DIFS; if it is an acknowledgment frame of a previous frame, it is transmitted after the elapsed SIFS (short IFS) without a backoff. The type and subtype of a frame can be identified by the type field and subtype field within the Frame Control (FC) field.

[0081] A QoS (Quality of Service) STA can transmit a frame after backoff, which is performed after the passage of the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC). Here, the frame for which AIFS[i] can be used can be a data frame or a management frame, and can also be a control frame rather than a response frame.

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

[0083] As previously mentioned, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, where the STA directly senses the medium. Virtual carrier sensing is intended to mitigate problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the STA's MAC can utilize the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available, provided that the STA currently using or authorized to use the medium is using it. Therefore, the value set as the NAV corresponds to the period during which the medium is scheduled to be used by the STA transmitting the frame, and the 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 frame's MAC header.

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

[0085] In order to reduce the possibility of collisions between multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism utilizing RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA1 may be a hidden node to STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA2 may be a hidden node to STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, it is possible to prevent a STA outside the transmission range of either STA1 or STA2, or a STA outside the carrier sensing range for transmission from STA1 or STA3, from attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0086] Specifically, STA1 can determine whether the channel is in use through carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy magnitude or signal correlation detected in the channel. Additionally, in terms of virtual carrier sensing, STA1 can determine the channel occupancy state using a NAV (network allocation vector) timer.

[0087] If the channel is idle during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. If STA2 receives the RTS frame, it can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0088] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) using the duration information included in the RTS frame. Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + data frame + SIFS + ACK frame) using the duration information included in the CTS frame. That is, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, it can set a NAV accordingly. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0089] If STA1 receives a CTS frame from STA2, it may transmit a data frame to STA2 after SIFS from the time the reception of the CTS frame is completed. If STA2 successfully receives the data frame, it may transmit an ACK frame to STA1 as an acknowledgment to the data frame after SIFS. STA3 may determine whether the channel is in use through carrier sensing when the NAV timer expires. If STA3 determines that the channel is not in use by another terminal during DIFS from the time the NAV timer expires, it may attempt channel access after a contention window (CW) based on random backoff has passed.

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

[0091] Based on instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MPDU (MAC PDU) to be transmitted. For example, upon receiving an instruction from the MAC layer requesting the start of transmission, the PHY layer switches to transmit mode and can construct the information provided by the MAC layer (e.g., data) into a frame for transmission. Additionally, if the PHY layer detects a valid preamble of a received frame, it monitors the preamble header and sends an instruction to the MAC layer indicating the start of reception.

[0092] As such, information transmission and reception in wireless LAN systems are carried out in the form of frames, and for this purpose, the Physical Layer Protocol Data Unit (PPDU) format is defined.

[0093] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIGNAL) field, and a Data field. The most basic (e.g., the non-HT (High Throughput)) PPDU format illustrated in FIG. 7 may consist only of Legacy-STF (Legacy-STF), Legacy-LTF (Legacy-LTF), Legacy-SIG (Legacy-SIG) fields and a Data field. In addition, 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 other types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF, (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the data field. More specific details will be described later with reference to FIG. 7.

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

[0095] The SIG field may contain various information related to the transmission and reception of the PPDU. For example, the L-SIG field consists 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 contain information regarding the modulation and coding rates of the data. For example, the 12-bit Length field may contain information regarding 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 non-HT, HT, VHT, or EHT PPDUs, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDUs, the value of the Length field may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0096] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), and PPDU TAIL bits, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiver. The PSDU corresponds to a MAC PDU defined at the MAC layer and may contain data generated or used by the upper layer. The PPDU TAIL bits may be used to return the encoder to a 0 state. Padding bits may be used to adjust the length of the data field to a predetermined unit.

[0097] A MAC PDU is 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 a MAC PDU and can be transmitted or received through the PSDU of the data portion in the PPDU format.

[0098] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may contain control information necessary for transmitting or receiving frames. The Duration / ID field may be set as the time for transmitting the corresponding frame. Address subfields may indicate the frame's receiver address, transmitter address, destination address, and source address, and some address subfields may be omitted. Specific details regarding each subfield of the MAC header, including Sequence Control, QoS Control, and HT Control subfields, can be found in the IEEE 802.11 standard document.

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

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

[0101] Various forms of PPDU have been used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format may also be referred to as the non-HT PPDU format (Fig. 7(a)).

[0102] The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format illustrated in FIG. 7(b) may be referred to as the HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field, without including L-STF, L-LTF, and L-SIG (not shown).

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

[0104] An example of the HE PPDU format (IEEE 802.11ax) includes the 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 the 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 multiple users (MU), but is not included in the HE PPDU format for single users (SU). Additionally, the HE trigger-based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field may vary to 8 µs. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16 µs. For example, RL-SIG can be configured identically to L-SIG. Based on the presence of RL-SIG, the receiving STA can determine that the received PPDU is a HE PPDU or the EHT PPDU described later.

[0105] The EHT PPDU format may include the EHT MU (multi-user) 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 RL-SIG following L-SIG, but it may include U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following RL-SIG.

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

[0107] The EHT-SIG is omitted in the EHT TB PPDU of FIG. 7(f) compared to the EHT MU PPDU. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0108] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated so that demodulation and decoding can be attempted even on legacy STAs, and mapped based on a defined 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 so that they can be demodulated and decoded by a STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) to obtain the information contained in the corresponding fields, and mapped based on a defined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

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

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

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

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

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

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

[0115] For example, the version-independent bits of U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version of the transmitted / received PPDU (e.g., EHT, UHR, etc.). The version-independent bits of 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 U-SIG may include information regarding the length of the TXOP (transmission opportunity) and information regarding the BSS color ID.

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

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

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

[0119] Preamble puncturing may refer to the transmission of a PPDU in which a signal is not present in one or more frequency units within the PPDU bandwidth. For example, the size of the frequency unit (or the resolution of preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or larger.

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

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

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

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

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

[0125] An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on the OFDMA technique. Additionally, an RU may be defined when transmitting signals to a single STA. Resources may be allocated on an RU basis for non-legacy STF, non-legacy LTF, and Data fields.

[0126] Applicable RU sizes can be defined according to the PPDU bandwidth. RUs 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 80 MHz PPDU, the RU placement for HE PPDU and EHT PPDU may differ. The applicable RU sizes, number of RUs, RU locations, DC (direct current) subcarrier locations and numbers, null subcarrier locations and numbers, and guard subcarrier locations and numbers for each PPDU bandwidth can be referred to as a tone-plan. For example, a tone-plan for a wide bandwidth may be defined as a multiple repetition of a tone-plan for a low bandwidth.

[0127] RUs of various sizes can be defined as 26-ton RUs, 52-ton RUs, 106-ton RUs, 242-ton RUs, 484-ton RUs, 996-ton RUs, 2x996-ton RUs, 3x996-ton RUs, etc. An MRU (multiple RU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers composed 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. In addition, multiple RUs constituting a single MRU may be continuous or non-continuous in the frequency domain.

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

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

[0130] Null data PPDU (NDP) announcement (NDPA) frame

[0131] In wireless LAN systems, sounding procedures / protocols are used to determine channel state information. A beamformer STA requesting channel state information can transmit a training signal to beamformee STA(s). The beamformee STA can measure the channel using the training signal (e.g., sounding NDP) and feed back an estimate of the channel state to the beamformer STA. The beamformer STA can derive a steering matrix or a beamforming matrix using the feedback estimate.

[0132] The beamforming STA can feed back estimates of the channel state to the beamformer STA through a compressed beamforming / CQI (channel quality indication) report frame. The information fed back may include single-user (SU) feedback, multi-user (MU) feedback, CQI feedback, etc.

[0133] The beamformer STA can transmit an NDP announcement and NDP to the beamformer(s) and receive feedback information from the beamformer STA(s). Additionally or alternatively, the beamformer STA can transmit an NDP announcement and NDP to the beamformer(s) and transmit a beamforming report poll (BFRP) or BFRP trigger to the beamformer(s) to receive feedback information from the beamformer(s).

[0134] NDP Notice (NDPA) frames can have multiple types or variants. For example, NDP Notice frames can be composed of various formats, such as VHT NDP Notice frames, HE NDP Notice frames, and EHT NDP Notice frames. These formats can be distinguished by the NDP Notice variant subfield within the sounding dialog token field.

[0135] FIG. 8 shows an exemplary format of an NDP notice frame to which the present disclosure may be applied.

[0136] An NDP notice frame may include one or more STA information (Info) fields. If an NDP notice frame includes only one STA Info field, the RA (receiver address) field may be set to the address of an STA capable of providing feedback. If an NDP notice frame includes multiple STA Info fields, the RA field may be set to a broadcast address.

[0137] The TA (transmitter address) field may be set to the address of the STA transmitting the NDP notice frame or to the bandwidth signaling TA of the STA transmitting the NDP notice frame. For example, in a non-HT or non-HT duplicate format, if the scrambling sequence (or scrambling sequence and service field) includes parameters for channel bandwidth, the TA field may be set to the bandwidth signaling TA.

[0138] The first two bits (B0 and B1) of the eight bits (B0-B7) of the sounding dialogue token field can be used to indicate the type / variant of the NDP notice frame. For example, for VHT or HE, B0 has a value of 0, and if the value of B1 is 0, it may indicate a VHT NDP notice frame, and if the value of B1 is 1, it may indicate an HE NDP notice frame. For example, an EHT NDP notice frame may correspond when both the values ​​of B0 and B1 are set to 1. If the value of B0 is 1 and the value of B1 is 0, it may correspond to a ranging NDP notice frame.

[0139] In the case of VHT STA, the first two bits (B0 and B1) of the sounding dialogue token field are defined as reserved, so VHT STA can recognize the sounding dialogue token number field of bits B2-B7 regardless of the values ​​of B0 and B1.

[0140] For VHT STA, the first two bits (B0 and B1) of the sounding dialogue token field are defined as reserved. Therefore, VHT STA can recognize the sounding dialogue token number field of bits B2-B7 regardless of the values ​​of B0 and B1.

[0141] For HE STA, the first bit (B0) of the sounding dialogue token field is defined as reserved, and the value of the second bit (B1) is defined as indicating a VHT NDP notice frame if the value of B1 is 0 and indicating an HE NDP notice frame if the value of B1 is 1. Therefore, HE STA can recognize the sounding dialogue token number field of bits B2-B7 when the value of B1 is 1, regardless of the value of B0.

[0142] The sounding dialogue token number subfield (bit positions B2-B7) may include a value for identifying an NDP notification frame selected by the beamformer.

[0143] An NDP notification frame may contain n (where n is an integer greater than or equal to 1) STA Info fields. Each STA Info field has a size of K octets, and K=2 in a VHT NDP notification frame, and K=4 in a HE NDP notification frame or an EHT NDP notification frame.

[0144] As shown in the example of Fig. 8(a), the STA Info field of the VHT NDP notification frame may include AID12, feedback type, and Nc index subfields.

[0145] The AID12 subfield contains 12 LSB (least significant bits) of the AID of the STA expected to process the subsequent NDP and prepare sounding feedback.

[0146] The feedback type subfield indicates the type of feedback required, and corresponds to SU if the value is 0 and MU if the value is 1.

[0147] The Nc index subfield indicates the value obtained by subtracting 1 from the number of columns (i.e., Nc) in the compressed beamforming feedback matrix (i.e., Nc-1) when the feedback type is MU. When it is SU, the Nc index field is reserved.

[0148] The example in Fig. 8(b) shows the format of the STA Info field of the HE NDP notification frame when the value of the AID11 field is not a specific value (e.g., 2047).

[0149] Values ​​of the AID11 subfield other than a specific value (e.g., 2047) include 11 LSB among the AIDs of the STA expected to process the subsequent NDP and prepare sounding feedback.

[0150] The partial BW Info subfield may include a 7-bit (B0-B6) RU start index and a 7-bit (B7-B13) RU end index. The RU index may be determined based on the bandwidth of the NDP notice frame, and the unit may be 26-tone RU. For example, to indicate a 26-tone RU index X, the value of the start / end RU index subfield may be set to X-1.

[0151] The feedback type and Ng subfield, in combination with the codebook size subfield, can indicate whether SU / MU / CQI feedback is requested for trigger-based (TB) sounding, Ng=4 or 16, and the quantization resolution. For non-TB sounding, the feedback type and Ng subfield and the codebook size subfield can indicate SU or CQI.

[0152] The disambiguation subfield is set to 1 to help prevent non-HE STAs (e.g., VHT STAs) from misinterpreting the field as an AID field.

[0153] The Nc subfield is set to a value of Nc-1. If the feedback type is SU or MU, Nc corresponds to the number of columns in the compressed beamforming feedback matrix, and if the feedback type is CQI, Nc may correspond to the number of space-time streams (STS). For NDP notice frames that have an AID11 subfield value other than 2047 and are individually addressed for a single STA, the Nc subfield may be reserved.

[0154] The example in Fig. 8(c) shows the format of the STA Info field of the HE NDP notification frame when the value of the AID11 field is a specific value (e.g., 2047).

[0155] The disallowed subchannel bitmap subfield indicates the 20 MHz subchannel(s) and 242-tone RU(s) present in the sounding NDPs announced by the NDP announcement frame, and the 242-tone RU(s) to be included in the requested sounding feedback. The lowest numbered bit of the disallowed subchannel bitmap corresponds to the 20 MHz subchannel located at the lowest frequency among all 20 MHz subchannels within the BSS bandwidth. Each subsequent bit in the bitmap corresponds to the next highest 20 MHz subchannel. A bit set to 1 in the bitmap may indicate that no energy is present in the sounding NDP associated with the NDP announcement frame. For each disallowed 20 MHz subchannel, the 242-tone RU that is closest in frequency to the corresponding 20 Hz subchannel may be disallowed for a PPDU using a specific tone plan. The STA(s) addressed by the NDP notice frame do not include tones from the 242-tone RU that are not allowed when determining the average SNR of STS 1 through Nc in generating the requested sounding feedback. If a 20 MHz subchannel and its corresponding 242-tone RU are allowed, the corresponding bit in the bitmap is set to 0.

[0156] The example in Fig. 8(d) shows the format of the STA Info field of the EHT NDP notification frame.

[0157] AID11 subfields can be defined as shown in Table 1. By default, AID11 subfields contain the identifier of the STA expected to process the subsequent NDP and prepare sounding feedback.

[0158] Description of AID Subfield Value NDP Notice Frame Type / Variant Applicability 0- Addressed for a combined AP, mesh AP, or IBSS STA where the STA Info field is located. Applicable to all variants 1- 2007- If the NDP notice frame is not a ranging variant, the STA Info field is addressed for a combined STA having the same AID as the value of the AID11 subfield. - If the NDP notice frame is a ranging variant, the STA Info field is addressed for an uncombined STA or combined STA having the same RSID / AID as the value of the RSID11 / AID11 subfield. - For EHT variants, the 2007 value is reserved. Applicable to all variants 2008- 2042 Reserved. Not applicable to all variants 2043- If the NDP notice frame is a ranging variant, the STA Info field is sequence Includes authentication code. - Otherwise, the AID11 value is reserved. Applicable only to the ranging variant. 2044 - If the NDP announcement frame is a ranging variant, the STA Info field includes a partial TSF (timing synchronization function). - Otherwise, the AID11 value is reserved. Applicable only to the ranging variant. 2045 - If the NDP announcement frame is a ranging variant, the STA Info field includes ranging measurement parameters. - Otherwise, the AID11 value is reserved. Applicable only to the ranging variant. 2046 Reserved. Not applicable to all variants. 2047 - If the NDP announcement frame is an HE variant, the STA Info field includes an unauthorized subchannel bitmap. - Otherwise, the AID11 value is reserved. Applicable only to the HE variant.

[0159] The partial BW subfield may include a 1-bit (B0) resolution subfield and an 8-bit (B1-B8) feedback bitmap. The resolution subfield indicates a resolution bandwidth (e.g., 20 MHz or 40 MHz) for each bit of the feedback bitmap subfield. The feedback bitmap subfield may indicate requests for each resolution bandwidth from low frequency to high frequency, and the first bit (B1) of the bitmap corresponds to the lowest resolution bandwidth. Each bit of the feedback bitmap is set to 1 when feedback for the corresponding resolution bandwidth is requested.

[0160] If the bandwidth of the EHT NDP notification frame is less than 320 MHz, the value of the resolution bit (B0) can be set to 0 to indicate a resolution of 20 MHz.

[0161] If the bandwidth of the EHT NDP notification frame is 20 MHz, B1 is set to 1 to indicate that feedback for 242-tone RU is requested, and B2-B8 can be reserved and set to 0.

[0162] When the bandwidth of the EHT NDP notice frame is 40 MHz, B1 and B2 indicate that feedback is requested at each of the two 242-tone RUs from low frequency to high frequency, and B3-B8 may be reserved and set to 0.

[0163] If the bandwidth of the PPDU carrying the EHT NDP notice frame is 80 MHz, B0 can be set to 0 to indicate a resolution of 20 MHz. If B1-B4 are all set to 1, it can indicate that feedback is requested for the 996-tone RU. Otherwise, B1-B4 indicate that feedback is requested for each of the four 242-tone RUs from the low frequency to the high frequency, and B5-B8 can be reserved and set to 0.

[0164] If the bandwidth of the PPDU carrying the EHT NDP notice frame is 160 MHz, B0 can be set to 0 to indicate a resolution of 20 MHz. If B1-B4 are all set to 1, it can indicate that feedback is requested for the lower 996-tone RU; otherwise, B1-B4 can indicate that feedback is requested for each of the four 242-tone RUs from the low frequency to the high frequency in the lower 80 MHz. If B5-B8 are all set to 1, it can indicate that feedback is requested for the upper 996-tone RU; otherwise, B5-B8 can indicate that feedback is requested for each of the four 242-tone RUs from the low frequency to the high frequency in the upper 80 MHz.

[0165] If the bandwidth of the PPDU carrying the EHT NDP notice frame is 320 MHz, B0 can be set to 1 to indicate a resolution of 40 MHz. If both B1 and B2 are set to 1, it can indicate that feedback is requested for the first 996-tone RU; otherwise, B1 and B2 can indicate that feedback is requested for each of the two 484-tone RUs from low frequency to high frequency in the first 80 MHz. If both B3 and B4 are set to 1, it can indicate that feedback is requested for the second 996-tone RU; otherwise, B3 and B4 can indicate that feedback is requested for each of the two 484-tone RUs from low frequency to high frequency in the second 80 MHz. If both B5 and B6 are set to 1, it may indicate that feedback is requested for the third 996-tone RU; otherwise, B5 and B6 may indicate that feedback is requested for each of the two 484-tone RUs from low to high frequency at the third 80 MHz. If both B7 and B8 are set to 1, it may indicate that feedback is requested for the fourth 996-tone RU; otherwise, B7 and B8 may indicate that feedback is requested for each of the two 484-tone RUs from low to high frequency at the fourth 80 MHz. The feedback tone set for each 484-tone RU may consist of the feedback tone sets of two 242-tone RUs that overlap with the 484-tone RU.

[0166] The partial bandwidth subfield can have values ​​such as the example in Table 2 depending on the relevant settings.

[0167]

[0168]

[0169] For TB sounding, the feedback type, Ng subfield, and codebook size subfield can be set according to the example in Table 3.

[0170]

[0171] For non-TB sounding, the feedback type and Ng subfield and codebook size subfield can be set according to the example in Table 4.

[0172]

[0173] The disambiguation subfield is set to 1 to help prevent non-EHT STAs (e.g., VHT STAs) from misinterpreting the field as an AID field.

[0174] In an EHT NDP announcement frame, RA is set to the broadcast address, and the following may apply. If the feedback type and Ng subfields and the codebook size subfield indicate SU or MU, the Nc index subfield is set to a value of Nc-1, where Nc corresponds to the number of columns in the compressed beamforming feedback matrix, and values ​​greater than 7 in the Nc index subfield are reserved. If the feedback type and Ng subfields and the codebook size subfield indicate CQI, the Nc index subfield is set to a value of Nc-1, where Nc corresponds to the number of STS (space-time streams), and values ​​greater than 7 in the Nc index subfield are reserved. One or more STA Info fields may exist.

[0175] In an EHT NDP notice frame having a single STA Info field, the RA field is set to an individual address, and the Nc index subfield may be reserved.

[0176] Trigger frame

[0177] FIG. 9 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0178] A trigger frame may allocate resources for one or more TB PPDU transmissions and request TB PPDU transmissions. The trigger frame may also include other information required by an STA that transmits a TB PPDU in response. The trigger frame may include common info and user info list fields in the frame body.

[0179] The common information field may include information that is commonly applied to one or more TB PPDU transmissions requested by the trigger frame, for example, trigger type, UL length, whether there is a subsequent trigger frame (e.g., More TF), whether there is a CS (channel sensing) request, UL BW (bandwidth), etc.

[0180] The user information list contains zero or more user info fields. Figure 9 illustrates an exemplary EHT variant user info field format.

[0181] The AID12 subfield basically indicates that it is a user information field for the STA with the corresponding AID. Additionally, if the AID12 field has a specific predetermined value, it may be utilized for other purposes, such as assigning a Random Access (RA)-RU or being configured as a special user info field. A special user info field is a user information field that does not contain user-specific information but includes extended common information not provided in the common information field. For example, a special user info field can be identified by an AID12 value of 2007, and a special user info field flag subfield within the common information field can indicate whether the special user info field is included.

[0182] The RU allocation subfield can indicate the size and location of the RU / MRU. To this end, the RU allocation subfield may 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. For example, as shown in Table 5 below, the mapping of B7-B1 of the RU allocation subfield can be defined together with the settings of B0 of the RU allocation subfield and the PS160 subfield. Table 5 shows an example of the encoding of the PS160 subfield and the RU allocation subfield of the EHT variant user information field.

[0183]

[0184]

[0185]

[0186]

[0187]

[0188] If B0 of the RU allocation subfield is set to 0, it indicates that the RU / MRU allocation is applied to the primary 80MHz channel, and if the value is set to 1, it indicates that the RU allocation is applied to the secondary 80MHz channel of the primary 160MHz. If B0 of the RU allocation subfield is set to 0, it indicates that the RU / MRU allocation is applied to the lower 80MHz of the secondary 160MHz, and if the value is set to 1, it indicates that the RU allocation is applied to the upper 80MHz of the secondary 160MHz.

[0189] In the trigger frame RU allocation table of Table 5, the parameter N can be calculated based on the formula N=2*X1+X0. For bandwidths of 80 MHz or less, the values ​​of PS160, B0, X0, and X1 can be set to 0. For 160 MHz and 320 MHz bandwidths, the values ​​of PS160, B0, X0, and X1 can be set as shown in Table 6. These settings represent the absolute frequency order for the primary and secondary 80 MHz and 160 MHz channels. The order from left to right indicates the order from lowest to highest frequency. The primary 80 MHz channel is designated as P80, the secondary 80 MHz channel as S80, and the secondary 160 MHz channel as S160.

[0190]

[0191] FIG. 10 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0192] Figure 10 illustrates an exemplary format of the EHT variant common info field in the trigger frame exemplified in Figure 9.

[0193] The trigger type subfield identifies the variant of the trigger frame.

[0194] The uplink length (UL(uplink) length) subfield indicates the value of the L-SIG LENGTH field of the solicited TB PPDU.

[0195] The more TF(trigger frame) subfield indicates whether the transmission of a subsequent trigger frame is scheduled.

[0196] The Carrier Sense Required (CS) subfield is set to 1 to indicate that the STAs identified in the User Info field use energy detection (ED) to sense the medium and must consider the medium state and network allocation vector (NAV) when determining whether to respond. The CS Required subfield is set to 0 to indicate that the STAs identified in the User Info field do not need to consider the medium state or NAV when determining whether to respond.

[0197] The uplink bandwidth (UL BW (bandwidth)) subfield, together with the uplink bandwidth extension (UL BW extension) subfield of the special user info field, indicates the bandwidth within the U-SIG field of the EHT TB PPDU.

[0198] If the trigger type subfield indicates a MU-RTS (request to send) trigger frame as the type of the corresponding trigger frame, B20-B1 of the EHT variant common info field corresponds to the trigger TXOP (transmission opportunity) sharing mode subfield. Otherwise, B20-B1 of the EHT variant common info field corresponds to the GI (guard interval) and HE / ETF-LTF type subfields. The GI and HE / ETF-LTF type subfield indicates the GI and HE / EHT-LTF types of the HE or EHT TB PPDU response. The trigger TXOP sharing mode subfield indicates the triggered TXOP mode.

[0199] B22 of the EHT variant common info field is reserved and set to 0.

[0200] The number of HE / EHT symbols subfield indicates the number of HE-LTF symbols present in the HE TB PPDU or the number of EHT-LTF symbols present in the EHT TB PPDU.

[0201] B26 of the EHT variant common info field is reserved and set to 0.

[0202] The LDPC (low-density parity check) extra symbol segment subfield indicates the status of the LDPC extra symbol segment. If the LDPC extra symbol segment exists in the requested HE or EHT TB PPDU, it is set to 1, otherwise it is set to 0.

[0203] The AP transmission power (AP Tx(transmit) power) subfield indicates the combined transmission power of the AP at the transmission antenna connector of all antennas used to transmit the triggering PPDU in units of dBm / 20MHz.

[0204] The pre-FEC (forward error correction) padding factor subfield and the PE disambiguity subfield are encoded identically to the corresponding subfields in HE-SIG-A or EHT-SIG.

[0205] The UL spatial reuse subfield includes the spatial reuse n subfield (1 ≤ n ≤ 4). When a trigger frame requests an EHT TB PPDU, each spatial reuse n subfield of the EHT variant common info field is determined based on the EHT spatial reuse 1 subfield or the EHT spatial reuse 2 subfield of the special user info field.

[0206] B53 of the EHT variant common info field is reserved and set to 0.

[0207] The HE / EHT P160 subfield is set to 0 to indicate that the TB PPDU requested at the primary 160 MHz is an EHT TB PPDU. The HE / EHT P160 subfield is set to 1 to indicate that the TB PPDU requested at the primary 160 MHz is an HE TB PPDU.

[0208] The special user info field flag subfield is always set to 0 in the EHT variant common info field and indicates that the special user info field is included in the trigger frame containing the EHT variant common info field.

[0209] The trigger dependent common info subfield exists optionally based on the value of the trigger type field.

[0210] Sounding motion for Coordinated Beamforming (Co-BF)

[0211] Multi-AP transmission technology is a new wireless transmission technology to be defined in next-generation wireless LAN systems (e.g., Wi-Fi 8, 802.11bn). Among these, Coordinated Beamforming (Co-BF) is a multi-AP cooperation technology that enables simultaneous transmission by multiple APs by eliminating or reducing interference directed toward STAs of adjacent BSSs, thereby improving system performance (throughput, latency, etc.). For example, each AP can control interference by designing and applying a precoder that can reduce interference directed toward overlapping BSS (OBSS) STAs.

[0212] Coordinated beamforming (Co-BF) enables two APs with multiple antennas to transmit simultaneously to non-AP STAs connected to each of the two APs. Here, each AP transmits PPDU to connected non-AP STAs within its Baseline Service (BSS). Here, by using information about the channel between each AP and the receiving STA of the other AP in the Co-BF transmission, interference to the non-AP STA(s) connected to the other AP can be minimized.

[0213] Hereinafter, an AP that secures a TXOP for operation / transmission of Co-coordinated beamforming (Co-BF) and transmits a frame / signaling for invitation / request to another AP may be referred to as a (Co-BF) coordinating AP, sharing AP, master AP, primary AP, etc., and an AP that initiates the Co-BF sounding procedure may be referred to as an initiating AP, etc., and for convenience of explanation in the description of the present disclosure below, may be referred to as the first AP (AP 1). Additionally, an AP receiving a frame / signaling for an invitation / request for Co-BF operation / transmission may be referred to as a (Co-BF) coordinated AP, shared AP, slave AP, secondary AP, etc., and an AP responding to a Co-BF sounding procedure may be referred to as a responding AP, etc., and for convenience of explanation in the description of the present disclosure below, it may be referred to as a second AP (AP 2).

[0214] Additionally, in Co-BF operation, to prevent preamble collisions caused by simultaneous transmission between the first PPDU transmitted by the first AP and the second PPDU transmitted by the second AP, the first PPDU and the second PPDU may include a common preamble (i.e., the same preamble).

[0215] For Co-BF, the BSS AP needs to receive downlink channel information directed toward the OBSS STA from the OBSS STA. Therefore, a new sounding feedback procedure must be defined for this process, which can be referred to as OBSS sounding or Co-BF sounding. Here, to avoid the complexity of the STA having to decode all OBSS packets, it is desirable to transmit NDP announcement (NDPA) frames and beamforming report poll (BFRP) trigger frames only to STAs within the BSS.

[0216] There are two possible approaches to Co-BF: Full Nulling, which eliminates all interference directed toward the OBSS STA, and Partial Nulling, which eliminates only a portion of the interference. Full Nulling, which eliminates all interference for simultaneous transmission, may seem intuitive. However, fundamentally, nulling consumes the transmission dimension (TX dimension) equal to the dimension being nulled. Therefore, if too many dimensions are consumed for nulling, the transmission dimension available to obtain beamforming gain for the STA within the BSS is reduced, which can lead to performance degradation. Consequently, when Partial Nulling is applied—eliminating only a portion of the interference rather than all of it—system performance can be improved by saving dimensions through partial nulling and utilizing those dimensions for obtaining beamforming gain within the BSS.

[0217] As described above, in a situation where partial nulling, which can be one method of Co-BF, is applied, the STA may need to additionally remove interference that was not sufficiently removed at the transmitting end through interference removal postcoding technology.

[0218] Example 1

[0219] The two technologies mentioned above are necessary for the actual implementation of Co-BF. Therefore, to initiate Co-BF, the capability to perform OBSS sounding and the capability to perform interference cancellation may be required. In other words, this information may need to be defined as a capability and exchanged during the initial negotiation phase.

[0220] Accordingly, the present disclosure proposes a method for defining the capabilities required for APs and STAs that must be exchanged in advance to operate C-BF.

[0221] Co-BF may require information about channel conditions to calculate a steering matrix applied to the transmitted signal to optimize reception at one or more receivers.

[0222] Co-BF sounding sequences / procedures may include Co-BF sequential NDP sounding sequences / procedures and Co-BF joint NDP sounding sequences / procedures. In a Co-BF sounding sequence / procedure, a Co-BF beamformer (e.g., non-AP STA) may measure the channel using training signals of NDPs transmitted from one or two beamformers (e.g., AP) and feed back transformed estimates for the channel state. For example, a Co-BF beamformer (e.g., non-AP STA) may return the estimated value of the channel state through EHT compressed beamforming / CQI (channel quality indication) reporting. The beamformer (e.g., AP) may use this estimate to derive a steering matrix.

[0223] Here, Co-BF sequential NDP sounding sequences / procedures are associated with / correspond to full nulling, and Co-BF joint NDP sounding sequences / procedures can be associated with / correspond to partial nulling.

[0224] Co-BF sounding can be an essential procedure for operating Co-BF. Therefore, the capabilities required to perform Co-BF sounding from the AP's perspective must be defined, and the AP needs to indicate whether it has the capability to support Co-BF.

[0225] In addition, Partial Nulling technology can be applied as a method for Co-BF. In Partial Nulling, a technique can be applied where the transmitter removes only a portion of the interference, and the receiver additionally removes the remaining interference. Therefore, from the perspective of the STA, a capability to perform interference cancellation is defined to decode a received signal based on Partial Nulling, and the STA needs to indicate whether it has partial nulling capability. In other words, the STA needs to indicate whether it has capability regarding the Co-BF joint NDP sounding sequence / procedure.

[0226] The information / fields for exchanging capabilities for Co-BF sounding are as follows, and at least one of the following may be used to exchange capabilities for Co-BF sounding.

[0227] - OBSS sounding initiation (or Co-BF sounding initiation)

[0228] It means a field / information indicating capability as a first AP (e.g., coordinating AP, sharing AP) capable of initiating Co-BF sounding (or OBSS sounding). Here, the field / information may indicate whether it has the function / capability to trigger NDP transmission (e.g., OBSS NDP or Co-BF NDP).

[0229] This field / information can be transmitted by the first AP (e.g., coordinating AP, initiating AP) to a non-AP STA and / or a second AP (e.g., coordinated AP, responding AP).

[0230] For example, this field / information can be transmitted by being included in the UHR MAC Capabilities Information field of the UHR capabilities element of an Association request / response frame.

[0231] - OBSS NDP transmission (or Co-BF NDP transmission)

[0232] In the Co-BF sounding (or OBSS sounding) procedure, this field / information may indicate whether the BSS second AP (e.g., coordinated AP, responding AP) has the ability / capability to read the NDPA frame and transmit the NDP.

[0233] This field / information can be transmitted by the second AP (e.g., coordinated AP, responding AP) to the non-AP STA and / or the first AP (e.g., coordinating AP, initiating AP).

[0234] For example, this field / information can be transmitted by being included in the UHR MAC Capabilities Information field of the UHR capabilities element of an Association request / response frame.

[0235] - Interference cancellation for partial nulling (or Co-BF joint NDP sounding sequence / procedure)

[0236] This information / field may indicate whether the STA has the ability / capability to apply interference removal-based postcoding that can be applied in a partial nulling-based system. In other words, this information / field may indicate whether the STA has the ability / capability to perform a Co-BF joint NDP sounding sequence / procedure.

[0237] This field / information can be transmitted by the STA to the first AP (e.g., coordinating AP, initiating AP) and / or the second AP (e.g., coordinated AP, responding AP).

[0238] For example, this field / information can be transmitted by being included in the UHR PHY Capabilities Information field of the UHR capabilities element of the Association request / response frame.

[0239] FIG. 11 is a drawing illustrating a PPDU format according to one embodiment of the present disclosure.

[0240] Referring to FIG. 11, a UHR PPDU that can be used in a UHR system may include some format features of HE TB PPDU and EHT TB PPDU. For example, a UHR PPDU (e.g., UHR TB PPDU) may be configured to include L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-STF, UHR-LTF(s), and data fields.

[0241] In addition, although not shown in FIG. 11, the UHR PPDU (e.g., UHR MU PPDU) may be configured to include an additional UHR SIG between the U-SIG and UHR-STF.

[0242] In FIG. 11, L-STF, L-LTF, and L-SIG may be referred to as legacy parts, RL-SIG, U-SIG, and UHR-SIG (if included) may be referred to as SIG parts, UHR-STF may be referred to as STF parts, and UHR-LTF may be referred to as LTF parts.

[0243] All or part of all parts (i.e., fields) of FIG. 11 may be divided into multiple subparts / subfields. Each field (and its subfields) may be transmitted in units of 4us * N (where N is an integer). Additionally, it may include a Guard Interval (GI) (or short GI) as defined in conventional wireless LAN systems. A common subcarrier frequency spacing value (delta_f = 312.5 kHz / N or 312.5 kHz * N, where N is an integer) may be applied to all of the illustrated fields, or a first delta_f may be applied to the first part (e.g., all of the legacy part, all / part of the SIG part), and a second delta_f (e.g., a value smaller than the first delta_f) may be applied to all / part of the remaining parts.

[0244] Some of the illustrated fields may be omitted, and the order of the fields is illustrated illustratively and may be changed in various ways.

[0245] The SIG part may include various control information for the transmitted PPDU. For example, it may include an STF part, an LTF part, and control information for decoding the data. For example, it may include all or part of the information included in the previously described HE-SIG-A information, information included in the HE-SIG-B information, information included in the U-SIG information, and information included in the EHT-SIG.

[0246] The STF part may include an STF sequence.

[0247] The LTF part may include a training field (i.e., an LTF sequence) for channel estimation.

[0248] The data field contains user data and may include packets for the upper layer. That is, it may include MPDU (MAC Frame).

[0249] For Co-BF transmission, the first PPDU transmitted by the first AP to the STA(s) connected to it and the second PPDU transmitted by the second AP to the STA(s) connected to it can each be configured in the PPDU format according to FIG. 11 described above, and a common preamble can be constructed for the first PPDU and the second PPDU.

[0250] FIG. 12 illustrates the operation of an STA device for a method for cooperative beamforming sounding according to one embodiment of the present disclosure.

[0251] FIG. 12 illustrates the operation of an STA device based on the previously proposed methods. The example in FIG. 12 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 12 may be omitted depending on the situation and / or configuration.

[0252] In FIG. 12, the first AP may be a coordinating AP, a sharing AP, or an initiating AP, and the second AP may be a coordinated AP, a shared AP, or a responding AP. Or the opposite is also possible.

[0253] Referring to FIG. 12, the STA transmits a first frame to the first AP (S1201).

[0254] Here, the first frame may include information regarding capability related to coordinated beamforming (Co-BF) sounding.

[0255] For example, information regarding the capability related to the Co-BF sounding within the first frame may indicate whether a Co-BF sequential NDP sounding procedure can be performed (or interference removal capability for full nulling) or whether a Co-BF joint NDP sounding procedure can be performed (or interference removal capability for partial nulling).

[0256] For example, the first frame may be an association request frame. Additionally, information regarding the capability related to the coordinated beamforming (Co-BF) sounding may be included in the UHR PHY capabilities information field within the association request frame.

[0257] STA receives a second frame from the first AP in response to the first frame (S1202).

[0258] Here, the second frame may include information regarding capability related to coordinated beamforming (Co-BF) sounding.

[0259] For example, if the first AP is a coordinating AP, a sharing AP, or an initiating AP, information regarding the capability related to the Co-BF sounding within the second frame may indicate whether the transmission of an NDP can be triggered to initiate a Co-BF sounding procedure.

[0260] Additionally, for example, if the first AP is a coordinated AP, a shared AP, or a responding AP, information regarding the capability related to the Co-BF sounding within the second frame may indicate whether an NDP can be transmitted in the Co-BF sounding procedure.

[0261] For example, the second frame may be an association response frame. Additionally, information regarding the capability related to the coordinated beamforming (Co-BF) sounding may be included within the UHR MAC capabilities information field in the association response frame.

[0262] The PPDU carrying the first frame and / or the second frame can be configured as shown in the example of FIG. 11.

[0263] The method described in the example of FIG. 12 can 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 be configured to generate a PPDU and transmit the PPDU through transceiver(s) (106). Furthermore, one or more memories (104) of the first device (100) may store instructions for performing the method described in the example of FIG. 12 or the examples described above when executed by one or more processors (102).

[0264] FIG. 13 illustrates the operation of an AP device for a method for cooperative beamforming sounding according to one embodiment of the present disclosure.

[0265] FIG. 13 illustrates the operation of an AP device based on the previously proposed methods. The example in FIG. 13 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 13 may be omitted depending on the situation and / or configuration.

[0266] In FIG. 13, the first AP may be a coordinating AP, a sharing AP, or an initiating AP, and the second AP may be a coordinated AP, a shared AP, or a responding AP. Or the opposite is also possible.

[0267] Referring to FIG. 13, the first AP receives a first frame from the STA (S1301).

[0268] Here, the first frame may include information regarding capability related to coordinated beamforming (Co-BF) sounding.

[0269] Here, the first frame may include information regarding capability related to coordinated beamforming (Co-BF) sounding.

[0270] For example, information regarding the capability related to the Co-BF sounding within the first frame may indicate whether a Co-BF sequential NDP sounding procedure can be performed (or interference removal capability for full nulling) or whether a Co-BF joint NDP sounding procedure can be performed (or interference removal capability for partial nulling).

[0271] For example, the first frame may be an association request frame. Additionally, information regarding the capability related to the coordinated beamforming (Co-BF) sounding may be included in the UHR PHY capabilities information field within the association request frame.

[0272] The first AP receives a second frame from the STA in response to the first frame (S1302).

[0273] Here, the second frame may include information regarding capability related to coordinated beamforming (Co-BF) sounding.

[0274] For example, if the first AP is a coordinating AP, a sharing AP, or an initiating AP, information regarding the capability related to the Co-BF sounding within the second frame may indicate whether the transmission of an NDP can be triggered to initiate a Co-BF sounding procedure.

[0275] Additionally, for example, if the first AP is a coordinated AP, a shared AP, or a responding AP, information regarding the capability related to the Co-BF sounding within the second frame may indicate whether an NDP can be transmitted in the Co-BF sounding procedure.

[0276] For example, the second frame may be an association response frame. Additionally, information regarding the capability related to the coordinated beamforming (Co-BF) sounding may be included within the UHR MAC capabilities information field in the association response frame.

[0277] The PPDU carrying the first frame and / or the second frame can be configured as shown in the example of FIG. 11.

[0278] The method described in the example of FIG. 13 can 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 be configured to generate a PPDU and transmit the PPDU through transceiver(s) (106). Furthermore, one or more memories (104) of the first device (100) may store instructions for performing the method described in the example of FIG. 13 or the examples described above when executed by one or more processors (102).

[0279] Example 2

[0280] To perform Co-BF sounding, the first AP (e.g., coordinating AP, initiating AP) can transmit an NDPA frame.

[0281] After transmitting the NDPA frame, an NDP transmitted from the second AP for a Co-BF sequential NDP sounding sequence / procedure or an NDP transmitted simultaneously from the first AP and the second AP for a Co-BF joint NDP sounding sequence / procedure may be transmitted. After transmitting the NDP(s), the first AP may transmit a BFRP trigger frame. Each Co-BF beamformer (e.g., STA) addressed by the BFRP trigger frame may respond with a TB PPDU (containing channel state information).

[0282] In a Co-BF sequential NDP sounding sequence / procedure, a sounding sequence / procedure for the first AP to collect channel state information from a STA associated with the first AP and a sounding sequence / procedure for the first AP to collect channel state information for the second AP from the same STA can be performed sequentially.

[0283] In the Co-BF joint NDP sounding sequence / procedure, after the first AP transmits an NDPA frame, the first AP and the second AP can simultaneously transmit NDP.

[0284] To define the Co-BF sounding sequence / procedure as described above, the OBSS AP must transmit an NDP after the NDPA frame of the first AP (e.g., BSS AP). Here, there is a problem in that the second AP (e.g., OBSS AP) cannot determine whether or not it is in a situation where it needs to transmit an NDP after the NDPA frame it has received. To solve this problem, the present disclosure proposes a method for signaling which AP should transmit the NDP to be triggered within an NDPA frame. In other words, the present disclosure proposes a method for triggering the transmission of an NDP by the OBSS in a Co-BF sounding operation.

[0285] To convey the information mentioned above, a new NDPA frame (e.g., a UHR NDPA frame) different from the existing NDPA frame (see Fig. 8) may be newly defined. However, since the existing NDPA frame does not have room (i.e., bits) to provide a new version indication (e.g., UHR), a new control frame subtype may be required to define the new NDPA frame. However, using a new control frame subtype for the new NDPA definition may be considered somewhat overdesigned.

[0286] On the other hand, since the trigger type of the trigger frame still has a lot of room (i.e., bits), the present disclosure proposes a method to define a new NDPA frame (e.g., defined as a new subtype of the trigger frame) by utilizing the trigger frame in particular.

[0287] According to the present embodiment, a new trigger type that can perform the role of an NDPA frame can be defined.

[0288] For example, the trigger type field of the current trigger frame has 7 elements / values ​​corresponding to 9 through 15 reserved, as shown in Table 7 below. One of these can be used to indicate the type of trigger frame that performs the role of a new NDPA frame. For example, the trigger frame may be referred to as "UHR NDPA trigger frame," etc.

[0289]

[0290] The trigger frame according to the present embodiment may include at least one of the following common information / fields. For example, at least one of the following common information / fields may be included within the common info field of the trigger frame.

[0291] - Version identifier

[0292] This information / field can indicate UHR to next-generation wireless LANs (e.g., next wi-fi). For example, a value of 0 for this information / field can indicate UHR, and values ​​from 1 onwards can indicate next-generation wireless LAN systems (e.g., beyond / next UHR).

[0293] Sounding dialog token

[0294] This information / field can identify whether the request / response exchanged between the sender and receiver during the Co-BR sounding process belongs to the same Co-BR sounding procedure.

[0295] - AP identifier (AP-ID: AP identifier)

[0296] This information / field may indicate which cooperating AP (e.g., second AP, coordinated AP, responding AP) is requesting an NDP by the NDPA frame. This information / field may indicate the AP-ID itself negotiated during the multi-AP cooperation process, or a value mapped to AID12 (or 11).

[0297] Additionally, or alternatively, an OBSS sounding instruction (or Co-BF sounding instruction) may be required. In other words, when an NDPA is transmitted after it has been determined to coordinate with a specific AP (e.g., a second AP, a coordinated AP, a responding AP), even if only an instruction indicating that the current sounding procedure is OBSS sounding (or Co-BF sounding) is transmitted, the AP can simply interpret the field and transmit an NDP.

[0298] The aforementioned common information / fields may be included within the trigger-dependent common info fields. In other words, the aforementioned common information / fields (at least one of a version identifier, a sounding dialog token, and an AP-ID) may be included in the trigger-dependent common info fields (see FIG. 10) within the trigger frame of a new trigger type corresponding to NDPA.

[0299] Alternatively, the aforementioned common information / field may be included in the common info field of a trigger frame of a new trigger type corresponding to NDPA. As shown in FIG. 10, the common info field of the trigger frame is 64 bits, and the aforementioned common information / field (at least one of a version identifier, a sounding dialogue token, and an AP-ID) may be included in the common info field using all or part of the 60 bits, excluding a 4-bit field indicating the trigger type.

[0300] Alternatively, the aforementioned common information / field may be included in a special user info field of a trigger frame of a new trigger type corresponding to NDPA. When the AID in the user info field has a value of 2007, the user info field may be configured as a special user info field. This special user info field may be composed of 40 bits, and the aforementioned common information / field (at least one of a version identifier, a sounding dialogue token, and an AP-ID) may be included in the special user info field using all or part of the 28 bits, excluding the 12 bits indicating the AID.

[0301] Additionally, the trigger frame according to the present embodiment may include at least one of the following user-specific information / fields. For example, at least one of the following user-specific information / fields may be included within the user info field of the trigger frame.

[0302] The description of the information / fields below is the same as the fields exemplified in FIG. 8(d) above, so a detailed description is omitted. That is, according to the present embodiment, at least one of the information / fields below may be included in the user info field of the trigger frame.

[0303] - AID 11 (or 12)

[0304] - Partial Bandwidth Information (partial BW Info)

[0305] - Nc index

[0306] - Feedback type and Ng

[0307] - Disambiguation

[0308] - Codebook size

[0309] The aforementioned user-specific information / fields may be included in the user info field of a trigger frame of a new trigger type corresponding to NDPA. The trigger frame of the newly defined trigger type has 40 bits for the user info field, and using all or part of the said 40 bits, the aforementioned user-specific information / fields (AID11 or 12, partial bandwidth information, Nc index, feedback type and Ng, ambiguity resolution, codebook size) may be included in the user info field of the trigger frame.

[0310] FIG. 14 illustrates a Co-BF sounding procedure according to one embodiment of the present disclosure.

[0311] In Fig. 14, AP 1 may correspond to a coordinating AP, an initiating AP, or a sharing AP, and AP 2 may correspond to a coordinated AP, a responding AP, or a shared AP. Also, the opposite is possible.

[0312] AP 1 can transmit a UHR NDPA trigger frame. FIG. 14 illustrates the case where the trigger frame is received by STA 1 and STA 2. The UHR NDPA trigger frame may include an AP-ID field / information to trigger the transmission of an NDP by AP 2, thereby enabling subsequent NDP transmission. That is, AP 2, identified by the AP-ID field / information, can transmit an NDP after a certain period of time from the transmission of the UHR NDPA trigger frame.

[0313] In addition, the user information field of the corresponding UHR NDPA trigger frame may contain all information necessary when STA1 and STA2 are sounding, and can be used when STA1 and STA2 are performing NDP sounding.

[0314] When the sounding of STA 1 and STA 2 is complete, AP1 can transmit a BFRP trigger frame to collect channel feedback from STA 1 and STA 2.

[0315] Although FIG. 14 illustrates a case where only AP 2 transmits NDP for convenience of explanation, in the case of a Co-BF sequential NDP sounding sequence / procedure, AP 1 can also transmit NDP sequentially, and in the case of a Co-BF joint NDP sounding sequence / procedure, AP 1 can also transmit NDP together with AP 2.

[0316] FIG. 15 illustrates the operation of an STA device for a method for cooperative beamforming sounding according to one embodiment of the present disclosure.

[0317] FIG. 15 illustrates the operation of an STA device based on the previously proposed methods. The example in FIG. 15 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 15 may be omitted depending on the situation and / or configuration.

[0318] In FIG. 15, the first AP is a coordinating AP, a sharing AP, or an initiating AP, and the second AP may be a coordinated AP, a shared AP, or a responding AP.

[0319] Referring to FIG. 15, the STA receives a third frame from the first AP to trigger the transmission of an NDP for Co-BF sounding (S1501).

[0320] Here, the third frame may be an NDP announcement trigger frame. In this case, based on a specific value of the trigger type field within the third frame, it may be indicated that the third frame is the NDP announcement trigger frame.

[0321] Additionally, the NDP announcement trigger frame may include an AP ID field indicating the identifier of the second AP for which the transmission of the NDP is requested.

[0322] Additionally, at least one of the trigger type field and the AP ID field may be included in the trigger dependent common field, common info field, or special user info field of the NDP announcement trigger frame.

[0323] STA receives an NDP for Co-BF sounding from the second AP (S1502).

[0324] STA receives a beamforming report poll (BFRP) trigger frame from the first AP (S1503).

[0325] STA transmits channel status information to the first AP based on the BFRP trigger frame (S1504).

[0326] Channel state information may include an estimated value of the channel state estimated based on the NDP received from the second AP (and / or the first AP), and may include, for example, a compressed beamforming / CQI report.

[0327] For example, channel status information can be included and transmitted within the TB PPDU.

[0328] The above third frame and / or the BFRP trigger frame and / or the PPDU carrying the channel status information can be configured as shown in the example of FIG. 11.

[0329] The method described in the example of FIG. 15 can 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 be configured to generate a PPDU and transmit the PPDU through transceiver(s) (106). Furthermore, one or more memories (104) of the first device (100) may store instructions for performing the method described in the example of FIG. 15 or the examples described above when executed by one or more processors (102).

[0330] FIG. 16 illustrates the operation of an AP device for a method for cooperative beamforming sounding according to one embodiment of the present disclosure.

[0331] FIG. 16 illustrates the operation of an STA device based on the previously proposed methods. The example in FIG. 16 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 16 may be omitted depending on the situation and / or setting.

[0332] In FIG. 16, the first AP is a coordinating AP, a sharing AP, or an initiating AP, and the second AP may be a coordinated AP, a shared AP, or a responding AP.

[0333] Referring to FIG. 16, the first AP transmits a third frame to the STA to trigger the transmission of an NDP for Co-BF sounding (S1601).

[0334] Here, the third frame may be an NDP announcement trigger frame. In this case, based on a specific value of the trigger type field within the third frame, it may be indicated that the third frame is the NDP announcement trigger frame.

[0335] Additionally, the NDP announcement trigger frame may include an AP ID field indicating the identifier of the second AP for which the transmission of the NDP is requested.

[0336] Additionally, at least one of the trigger type field and the AP ID field may be included in the trigger dependent common field, common info field, or special user info field of the NDP announcement trigger frame.

[0337] The first AP transmits a beamforming report poll (BFRP) trigger frame to the STA (S1602).

[0338] The first AP receives channel status information from the STA based on a BFRP trigger frame (S1603).

[0339] The channel state information may include an estimated value of the channel state estimated based on the NDP received by the STA from the second AP (and / or from the first AP), and may include, for example, a compressed beamforming / CQI report.

[0340] For example, channel status information can be included and transmitted within the TB PPDU.

[0341] The above third frame and / or the BFRP trigger frame and / or the PPDU carrying the channel status information can be configured as shown in the example of FIG. 11.

[0342] The method described in the example of FIG. 16 can 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 be configured to generate a PPDU and transmit the PPDU through transceiver(s) (106). Furthermore, one or more memories (104) of the first device (100) may store instructions for performing the method described in the example of FIG. 16 or the examples described above when executed by one or more processors (102).

[0343] The Co-BF sounding operation / procedure according to Example 2 can be performed after the procedure of Example 1 described above. That is, after exchanging the capability for Co-BF sounding between the STA and AP according to Example 1, the Co-BF sounding operation / procedure proposed in Example 2 can be performed.

[0344] Example 3

[0345] As mentioned above, sounding and feedback of OBSS channel information are essential for the practical operation of Co-BF. To support OBSS sounding (or Co-BF sounding), the definition of UHR NDPA frames is essential, as it is necessary to inform the OBSS AP of the parameters required to transmit NDP. However, since the NDPA version indication bits are already fully used to indicate existing NDPA versions, it is difficult to explicitly apply a version indication. Therefore, UHR NDPA frames can be defined based on the version indication of EHT among NDPA types. That is, in a situation indicated as EHT NDPA, if the first user field is a special user info field (e.g., AID=2047), the corresponding NDPA frame can be parsed as a UHR NDPA frame.

[0346] Here, since a single special user info field is insufficient to convey all Co-BF related parameters, a second user info field may be additionally defined. For example, the AID11 of the second user info field conveys the AP-ID (identifier) ​​of the OBSS AP, and Co-BF related parameters may be conveyed in the subsequent fields.

[0347] However, when applying the above method, there may be a disadvantage that the AP-ID can only be used as a value between 2008 and 2044 because the AP's AID must be indicated only by AID11. In other words, the first 11 bits of the second user information field represent the OBSS AP's AID11, but if an 11-bit AP-ID is applied in this way, there is a disadvantage that the remaining fields of AID12 cannot be used as the AP-ID.

[0348] Accordingly, the present disclosure proposes a method to make more AID12 values ​​available for AP-ID allocation by indicating the AID field present in the second user information field as AID12 instead of AID11 (i.e., setting the first 12 bits of the second user information field to AID12).

[0349] In other words, this embodiment proposes a method to more effectively transmit the ID of the OBSS AP among the Co-BF information that must be transmitted within the NDPA frame during the Co-BF sounding process.

[0350] The AID12 field of the second user information field is a field that can indicate the ID of the AP (specified for NDP transmission).

[0351] The range of values ​​that can be used for AP-ID may be limited to 2008 to 2044, 2047, or 4056 to 4092. Here, the reason why 2048 to 4055 cannot be used is that, from the perspective of the EHT STA, the first 11 bits of the second user information field will be read as AID11, so values ​​that could be misinterpreted as 0 to 2007, which the EHT STA can address itself from among the AID12 values ​​where MSB (B11) is 1, must be excluded.

[0352] If the NDP Announcement Type of an NDPA frame is EHT (value 3) and the AID of the first STA information field is a specific value (e.g., 2047), the NDPA frame can be interpreted / recognized as a UHR NDPA frame. The AID 12 field proposed in this disclosure may be composed of B0-B11 of the second user information field present in the UHR NDPA frame.

[0353] The operation of transmitting a UHR NDPA frame according to Example 3 can be performed within the Co-BF sounding procedure according to Example 2, which is performed after the procedure of Example 1 described above. That is, after exchanging capabilities for Co-BF sounding between the STA and AP according to Example 1, the UHR NDPA frame proposed in Example 3 can be used to trigger the transmission of NDP within the Co-BF sounding procedure according to Example 2.

[0354] For example, referring again to FIGS. 15 and 16 above, the third frame may be an ultra-high reliability (UHR) NDP announcement frame. In this case, a field for indicating the identifier of the second AP for which the transmission of the NDP is requested may be composed of the first 12 bits of the second user info field of the UHR NDP announcement frame.

[0355] Unlike the NDP sounding method in existing wireless LAN systems, the Co-BF NDP sounding method according to the examples of the present disclosure has the feature of supporting OBSS sounding as described above. Accordingly, since channel information for OBSS STAs can be obtained, the effect of enabling smooth Co-BF operation can be achieved. In addition, AP / non-AP STAs can decide whether to participate in or not participate in a specific Co-BF transmission based on their capability for Co-BF sounding.

[0356] The embodiments described above are combinations of the components and features of the present disclosure in a specific form. Each component or feature should be considered optional unless otherwise explicitly stated. Each component or feature may be implemented in a form not combined with other components or features. Additionally, it is possible to construct 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 obvious that embodiments may be constructed by combining claims that are not explicitly related in the claims, or that they may be included as new claims by amendment after filing.

[0357] It is obvious to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential features of the present disclosure. Accordingly, the detailed description set forth above should not be interpreted restrictively in all respects and should be considered exemplary. The scope of the present disclosure shall be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0358] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that enable operations according to the methods of various embodiments to be executed on a device or computer, and a non-transitory computer-readable medium on which such software or instructions, etc. are stored and executable on a device or computer. Instructions that may be used to program a processing system to perform the features described in the present disclosure may be stored on or within a storage medium or a computer-readable storage medium, and the features described in the present disclosure may be implemented using a computer program product comprising such a storage medium. The storage medium may 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 may 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 may optionally include one or more storage devices located remotely from the processor(s). Memory or alternatively, non-volatile memory device(s) within memory comprises a non-transient computer-readable storage medium. The features described in this disclosure may be stored in any one of the machine-readable media and integrated into software and / or firmware that can control the hardware of a processing system and allow the processing system to interact with other mechanisms utilizing results according to the embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0359] Although the method proposed in this disclosure has been described with an example applied to an IEEE 802.11-based system, it 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 first frame to a first access point (AP) by a station (STA); and The method includes the step of receiving a second frame from the first AP in response to the first frame by the above STA, A method in which the first frame and / or the second frame include information regarding capability related to coordinated beamforming (Co-BF) sounding.

2. In Paragraph 1, A method in which information regarding the capability related to the Co-BF sounding within the second frame indicates whether the transmission of a null data packet (NDP) can be triggered to initiate a Co-BF sounding procedure.

3. In Paragraph 1, A method in which information regarding the capability related to the Co-BF sounding within the second frame indicates whether an NDP can be transmitted in the Co-BF sounding procedure.

4. In Paragraph 1, A method in which information regarding the capability related to the Co-BF sounding within the first frame indicates whether a Co-BF sequential NDP sounding procedure can be performed or a Co-BF joint NDP sounding procedure can be performed.

5. In Paragraph 1, A method in which the first frame is an association request frame and the second frame is an association response frame.

6. In Paragraph 1, The step of receiving a third frame to trigger the transmission of an NDP for Co-BF sounding from the first AP by the above STA; and A method further comprising the step of receiving the NDP from the second AP by the above STA.

7. In Paragraph 6, The step of receiving a beamforming report poll (BFRP) trigger frame from the first AP by the above STA; and A method comprising the step of transmitting channel state information to the first AP based on the BFRP trigger frame by the above STA.

8. In Paragraph 6, The above third frame is an NDP announcement trigger frame, and A method in which the third frame is indicated as the NDP announcement trigger frame based on a specific value of the trigger type field within the third frame.

9. In Paragraph 8, A method in which the above NDP announcement trigger frame includes an AP ID field indicating the identifier of the second AP to which the transmission of the above NDP is requested.

10. In Paragraph 8, A method in which at least one of the trigger type field and the AP ID field is included in the trigger dependent common field, common info field, or special user info field of the NDP announcement trigger frame.

11. In Paragraph 6, The above third frame is an UHR (ultra high reliability) NDP announcement frame, and A method in which a field for indicating the identifier of the second AP to which the transmission of the above NDP is requested is composed of the first 12 bits of the second user info field of the above UHR NDP announcement frame.

12. The station (STA) device is: One or more transceivers; and It includes one or more processors connected to the above one or more transmitters and receivers, and The above one or more processors are: Transmit the first frame to the first access point (AP), and It is configured to receive a second frame from the first AP as a response to the first frame, and The device, wherein the second frame above includes information regarding the capability of the first AP for coordinated beamforming (Co-BF) sounding.

13. A step of receiving a first frame from a station (STA) by a first access point (AP); and The method includes the step of transmitting a second frame to the STA in response to the first frame by the first AP, and A method in which the second frame includes information regarding the capability of the first AP to coordinate beamforming (Co-BF) sounding.

14. The first access point (AP) device is: One or more transceivers; and It includes one or more processors connected to the above one or more transmitters and receivers, and The above one or more processors are: Receive a first frame from a station (STA), and The above STA is configured to transmit a second frame in response to the first frame, and The device, wherein the second frame above includes information regarding the capability of the first AP for coordinated beamforming (Co-BF) sounding.

15. In a processing device configured to control a station (STA) in a wireless LAN system, the processing device comprises: One or more processors; and A processing device comprising one or more computer memories that are operably connected to one or more processors and store instructions for performing a method according to any one of claims 1 to 11 based on execution by one or more processors.

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

Images