Method and apparatus for configuring NDPA frame for CQI reporting by new unit in wireless LAN system

Abstract

Proposed are a method and an apparatus for configuring an NDPA frame for CQI reporting by a new unit in a wireless LAN system. Specifically, a reception STA receives an NDPA frame from a transmission STA. The reception STA receives an NDP frame from the transmission STA. The reception STA transmits a feedback frame to the transmission STA on the basis of the NDPA frame and the NDP frame. The NDPA frame includes a feedback type and Ng subfield, a codebook size subfield, and a reserved subfield. One bit of the reserved subfield includes information on a unit of a CQI to be fed back. The feedback frame includes a CQI.

Description

Method and device for configuring NDPA frame for CQI report in new unit in wireless LAN system

[0001] The present specification relates to a technique for constructing an NDPA frame to perform a CQI report in a new unit in a wireless LAN system, and more specifically, to a method and device for supporting CQI feedback in units of 242-tone RU or more through reserved bits of the NDPA frame and constructing a new CQI report field.

[0002] Wireless local area networks (WLANs) have been improved in various ways. For example, the IEEE 802.11ax standard proposed an improved communication environment using orthogonal frequency division multiple access (OFDMA) and downlink multi-user multiple input, multiple output (DL MU MIMO) techniques.

[0003] This specification proposes technical features that can be utilized in a new communications standard. For example, the new communications standard could be the Extreme High Throughput (EHT) standard, which is currently under discussion. The EHT standard could utilize newly proposed increased bandwidth, an improved PHY layer protocol data unit (PPDU) structure, improved sequences, and the Hybrid Automatic Repeat Request (HARQ) technique. The EHT standard could also be referred to as the IEEE 802.11be standard.

[0004] New wireless LAN standards may allow for an increased number of spatial streams. This may necessitate improvements to signaling techniques within the wireless LAN system to properly utilize these increased spatial streams.

[0005] This specification proposes a method and device for configuring an NDPA frame to report CQI in a new unit in a wireless LAN system.

[0006] An example of this specification proposes a method of constructing an NDPA frame to report CQI in new units.

[0007] The present embodiment can be performed in a network environment that supports a next-generation wireless LAN system (UHR (Ultra High Reliability) wireless LAN system or next wi-fi). The next-generation wireless LAN system is a wireless LAN system that improves the 802.11be system and can satisfy backward compatibility with the 802.11be system.

[0008] The present embodiment is performed in a receiving STA, and the receiving STA may correspond to at least one STA (station) or beamformer. The transmitting STA may correspond to an AP (access point) or beamformer.

[0009] The present embodiment proposes a method for constructing an NDPA frame to support CQI feedback in units of 242-tone RUs or more. In particular, the present embodiment proposes a method for supporting CQI feedback in units of 242-tone RUs or more through reserved bits of the NDPA frame and constructing a new CQI reporting field.

[0010] A receiving STA (station) receives an NDPA (Null Data Packet Announcement) frame from a transmitting STA.

[0011] The above receiving STA receives an NDP frame from the above transmitting STA.

[0012] The receiving STA transmits a feedback frame to the transmitting STA based on the NDPA frame and the NDP frame.

[0013] The above NDPA frame includes a Feedback Type And Ng subfield, a Codebook Size subfield, and a Reserved subfield.

[0014] One bit of the above Reserved subfield contains information about the unit of the CQI (Channel Quality Indicator) being fed back. The feedback frame includes the CQI. In this case, the CQI can be fed back for each spatial stream in the RU unit to which the CQI is fed back within the channel bandwidth measured by the NDPA.

[0015] If the above 1 bit is set to 0, the unit of the fed-back CQI may be a 26-tone RU (Resource Unit). If the above 1 bit is set to 1, the unit of the fed-back CQI may be a 242-tone RU, a 484-tone RU, or a 996-tone RU.

[0016] That is, the present embodiment proposes a method to support CQI feedback in new units (units of 242-tone RU or more) through reserved bits of the NDPA frame.

[0017] Previously, when the feedback type was CQI, CQI in units of 26-tone RU was fed back for each spatial stream, but this embodiment has the effect of reducing feedback overhead and increasing channel efficiency by being able to feed back CQI in units of 242-tone RU or more.

[0018] Figure 1 illustrates an example of a transmitting device and / or a receiving device of the present specification.

[0019] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0020] Figure 3 is a diagram illustrating a general link setup process.

[0021] Figure 4 illustrates one embodiment of a multi-link (ML).

[0022] FIG. 5 illustrates a PPDU (physical protocol data unit or physical layer (PHY) protocol data unit) transmitted / received by an STA of this specification.

[0023] Figure 6 is a diagram showing the layout of resource units (RUs) used for 20MHz PPDU.

[0024] Figure 7 is a diagram showing the layout of resource units (RUs) used for 40MHz PPDU.

[0025] Figure 8 is a diagram showing the layout of resource units (RUs) used for 80MHz PPDU.

[0026] Figure 9 shows the operation according to UL-MU.

[0027] Figure 10 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0028] Figure 11 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0029] Figure 12 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0030] Figure 13 shows an example of a header of a MAC frame.

[0031] FIG. 14 illustrates a modified example of a transmitting device and / or a receiving device of the present specification.

[0032] Figure 15 shows an example of EHT non-TB sounding.

[0033] Figure 16 shows an example of EHT TB sounding.

[0034] Figure 17 shows an example of the EHT NDP Announcement frame format.

[0035] Fig. 18 is a flowchart illustrating the operation of a transmitting device according to the present embodiment.

[0036] Fig. 19 is a flowchart illustrating the operation of a receiving device according to the present embodiment.

[0037] FIG. 20 is a flowchart illustrating a procedure for performing sounding by configuring an NDPA frame to report a CQI in a new unit according to the present embodiment.

[0038] FIG. 21 is a flowchart illustrating a procedure for performing sounding by receiving an NDPA frame configured to perform a CQI report in a new unit according to the present embodiment.

[0039] In this specification, “A or B” can mean “only A,” “only B,” or “both A and B.” In other words, “A or B” in this specification can be interpreted as “A and / or B.” For example, “A, B or C” in this specification can mean “only A,” “only B,” “only C,” or “any combination of A, B, and C.”

[0040] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0041] In this specification, “at least one of A and B” can mean “only A,” “only B,” or “both A and B.” Additionally, in this specification, the expressions “at least one of A or B” or “at least one of A and / or B” can be interpreted identically to “at least one of A and B.”

[0042] In addition, parentheses used in this specification may mean “for example.” Specifically, when “control information (UHR-Signal field)” is indicated, the “UHR-Signal field” may be suggested as an example of “control information.” In other words, the “control information” in this specification is not limited to the “UHR-Signal field,” and the “UHR-Signal field” may be suggested as an example of “control information.” In addition, even when indicated as “control information (UHR-Signal field),” the “UHR-Signal field” may be suggested as an example of “control information.”

[0043] Additionally, as used herein, “a / an” can mean “at least one” or “one or more.” Additionally, terms ending in “(s)” can mean “at least one” or “one or more.”

[0044] Additionally, the expressions “based on” or “on the basis of” or “according to” used herein mean “based at least in part on” and not “based solely on.”

[0045] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0046] The following examples of this specification can be applied to various wireless communication systems. For example, the following examples of this specification can be applied to wireless local area network (WLAN) systems. For example, the present specification can be applied to the IEEE 802.11a / g / n / ac / ax / be / bn standards. In addition, the examples of this specification can be applied to the Ultra High Reliability (UHR) standard or the next-generation wireless LAN standard that enhances IEEE 802.11bn. In addition, the examples of this specification can be applied to mobile communication systems. For example, the examples of this specification can be applied to mobile communication systems based on Long Term Evolution (LTE) and its evolution based on the 3rd Generation Partnership Project (3GPP) standard.

[0047] In order to explain the technical features of this specification, the technical features to which this specification can be applied are described below.

[0048] Figure 1 illustrates an example of a transmitting device and / or a receiving device of the present specification.

[0049] An example of FIG. 1 can perform various technical features described below. FIG. 1 relates to at least one STA (station). For example, the STA (110, 120) of the present specification may also be referred to by various names such as a mobile terminal, a wireless device, a Wireless Transmit / Receive Unit (WTRU), a User Equipment (UE), a Mobile Station (MS), a Mobile Subscriber Unit, or simply a user. The STA (110, 120) of the present specification may also be referred to by various names such as a network, a base station, a Node-B, an access point (AP), a repeater, a router, a relay, etc. The STA (110, 120) of the present specification may also be referred to by various names such as a receiving apparatus, a transmitting apparatus, a receiving STA, a transmitting STA, a receiving device, a transmitting device, etc.

[0050] For example, STA (110, 120) may perform the role of an AP (access point) or a non-AP role. That is, STA (110, 120) of the present specification may perform the functions of an AP and / or a non-AP. In the present specification, AP may also be indicated as an AP STA.

[0051] The STA (110, 120) of this specification can support various communication standards other than the IEEE 802.11 standard. For example, it can support communication standards according to the 3GPP standard (e.g., LTE, LTE-A, 5G NR standard). In addition, the STA of this specification can be implemented in various devices such as a mobile phone, a vehicle, a personal computer, etc. In addition, the STA of this specification can support communication for various communication services such as voice calls, video calls, data communications, and autonomous driving (self-driving, autonomous-driving).

[0052] In this specification, STA (110, 120) may include a medium access control (MAC) and a physical layer interface for a wireless medium that follow the provisions of the IEEE 802.11 standard.

[0053] Based on the sub-drawing (a) of Fig. 1, STA (110, 120) is described as follows.

[0054] The first STA (110) may include a processor (111), a memory (112), and a transceiver (113). The illustrated processor, memory, and transceiver may each be implemented as separate chips, or at least two blocks / functions may be implemented through a single chip.

[0055] The transceiver (113) of the first STA performs signal transmission and reception operations. Specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0056] For example, the first STA (110) can perform the intended operation of the AP. For example, the processor (111) of the AP can receive a signal through the transceiver (113), process the received signal, generate a transmission signal, and perform control for signal transmission. The memory (112) of the AP can store a signal received through the transceiver (113) (i.e., a reception signal) and store a signal to be transmitted through the transceiver (i.e., a transmission signal).

[0057] For example, the second STA (120) can perform the intended operation of a non-AP STA. For example, the transceiver (123) of the non-AP performs signal transmission and reception operations. Specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0058] For example, the processor (121) of the Non-AP STA can receive a signal through the transceiver (123), process the received signal, generate a transmission signal, and perform control for signal transmission. The memory (122) of the Non-AP STA can store a signal received through the transceiver (123) (i.e., a reception signal) and store a signal to be transmitted through the transceiver (i.e., a transmission signal).

[0059] For example, in the specification below, the operation of a device indicated as AP may be performed in the first STA (110) or the second STA (120). For example, if the first STA (110) is an AP, the operation of the device indicated as AP may be controlled by the processor (111) of the first STA (110), and a related signal may be transmitted or received through a transceiver (113) controlled by the processor (111) of the first STA (110). In addition, control information related to the operation of the AP or a transmission / reception signal of the AP may be stored in the memory (112) of the first STA (110). In addition, when the second STA (110) is an AP, the operation of the device indicated as an AP is controlled by the processor (121) of the second STA (120), and a related signal can be transmitted or received through a transceiver (123) controlled by the processor (121) of the second STA (120). In addition, control information related to the operation of the AP or the transmission / reception signal of the AP can be stored in the memory (122) of the second STA (110).

[0060] For example, in the specification below, the operation of a device indicated as a non-AP (or User-STA) may be performed in the STA (110) or the second STA (120). For example, if the second STA (120) is a non-AP, the operation of the device indicated as a non-AP may be controlled by the processor (121) of the second STA (120), and a related signal may be transmitted or received through a transceiver (123) controlled by the processor (121) of the second STA (120). In addition, control information related to the operation of the non-AP or the transmission / reception signal of the AP may be stored in the memory (122) of the second STA (120). For example, if the first STA (110) is a non-AP, the operation of a device indicated as a non-AP is controlled by the processor (111) of the first STA (110), and a related signal may be transmitted or received through a transceiver (113) controlled by the processor (111) of the first STA (120). In addition, control information related to the operation of the non-AP or the transmission / reception signal of the AP may be stored in the memory (112) of the first STA (110).

[0061] In the following specification, devices called (transmitting / receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting / receiving) Terminal, (transmitting / receiving) device, (transmitting / receiving) apparatus, network, etc. may refer to the STA (110, 120) of FIG. 1. For example, devices indicated as (transmitting / receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting / receiving) Terminal, (transmitting / receiving) device, (transmitting / receiving) apparatus, network, etc. without specific drawing symbols may also refer to the STA (110, 120) of FIG. 1. For example, in the example below, the operation of various STAs transmitting and receiving signals (e.g., PPPDU) may be performed by the transceiver (113, 123) of FIG. 1. In addition, in the example below, the operation of various STAs generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals may be performed by the processor (111, 121) of FIG. 1.For example, an example of an operation that generates a transmission / reception signal or performs data processing or operation in advance for a transmission / reception signal may include 1) an operation of determining / obtaining / configuring / computing / decoding / encoding bit information of a subfield (SIG, STF, LTF, Data) field included in a PPDU, 2) an operation of determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) used for a subfield (SIG, STF, LTF, Data) field included in a PPDU, 3) an operation of determining / configuring / obtaining a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an extra sequence applied to SIG) used for a subfield (SIG, STF, LTF, Data) field included in a PPDU, 4) a power control operation and / or a power saving operation applied to an STA, 5) an operation related to determining / obtaining / configuring / computing / decoding / encoding an ACK signal, etc. Additionally, in the examples below, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / computing / decoding / encoding transmission / reception signals can be stored in the memory (112, 122) of FIG. 1.

[0062] The device / STA of the sub-drawing (a) of the above-described Fig. 1 can be modified as in the sub-drawing (b) of Fig. 1. Hereinafter, the STA (110, 120) of the present specification will be described based on the sub-drawing (b) of Fig. 1.

[0063] For example, the transceiver (113, 123) illustrated in sub-drawing (b) of FIG. 1 may perform the same function as the transceiver illustrated in sub-drawing (a) of FIG. 1 described above. For example, the processing chip (114, 124) illustrated in sub-drawing (b) of FIG. 1 may include a processor (111, 121) and a memory (112, 122). The processor (111, 121) and the memory (112, 122) illustrated in sub-drawing (b) of FIG. 1 may perform the same function as the processor (111, 121) and the memory (112, 122) illustrated in sub-drawing (a) of FIG. 1 described above.

[0064] The mobile terminal, wireless device, Wireless Transmit / Receive Unit (WTRU), User Equipment (UE), Mobile Station (MS), Mobile Subscriber Unit, user, user STA, network, Base Station, Node-B, Access Point (AP), repeater, router, relay, receiving device, transmitting device, receiving STA, transmitting STA, receiving Device, transmitting Device, receiving Apparatus, and / or transmitting Apparatus described below may refer to the STA (110, 120) illustrated in the sub-drawings (a) / (b) of FIG. 1, or may refer to the processing chip (114, 124) illustrated in the sub-drawing (b) of FIG. 1. That is, the technical feature of the present specification may be performed in the STA (110, 120) illustrated in the sub-drawings (a) / (b) of FIG. 1, or may be performed only in the processing chip (114, 124) illustrated in the sub-drawings (b) of FIG. 1. For example, the technical feature that the transmitting STA transmits a control signal may be understood as a technical feature that the control signal generated in the processor (111, 121) illustrated in the sub-drawings (a) / (b) of FIG. 1 is transmitted through the transceiver (113, 123) illustrated in the sub-drawings (a) / (b) of FIG. 1. Alternatively, the technical feature that the transmitting STA transmits a control signal may be understood as a technical feature that the control signal to be transmitted to the transceiver (113, 123) is generated in the processing chip (114, 124) illustrated in the sub-drawings (b) of FIG. 1.

[0065] For example, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal being received by a transceiver (113, 123) illustrated in sub-drawing (a) of FIG. 1. Alternatively, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal received by a transceiver (113, 123) illustrated in sub-drawing (a) of FIG. 1 being acquired by a processor (111, 121) illustrated in sub-drawing (a) of FIG. 1. Alternatively, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal received by a transceiver (113, 123) illustrated in sub-drawing (b) of FIG. 1 being acquired by a processing chip (114, 124) illustrated in sub-drawing (b) of FIG.

[0066] Referring to the sub-drawing (b) of FIG. 1, software code (115, 125) may be included in the memory (112, 122). The software code (115, 125) may include instructions that control the operation of the processor (111, 121). The software code (115, 125) may be included in various programming languages.

[0067] The processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and / or a data processing device. The processor may be an application processor (AP). For example, the processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). For example, the processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may be a SNAPDRAGON™ series processor manufactured by Qualcomm®, an EXYNOSTM series processor manufactured by Samsung®, an A series processor manufactured by Apple®, a HELIO™ series processor manufactured by MediaTek®, an ATOM™ series processor manufactured by INTEL®, or an enhanced processor thereof.

[0068] In this specification, uplink may mean a link for communication from a non-AP STA to an AP STA, and uplink PPDU / packet / signal, etc. may be transmitted through the uplink. In addition, in this specification, downlink may mean a link for communication from an AP STA to a non-AP STA, and downlink PPDU / packet / signal, etc. may be transmitted through the downlink.

[0069] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0070] The upper part of Figure 2 shows the structure of the infrastructure BSS (basic service set) of IEEE (institute of electrical and electronic engineers) 802.11.

[0071] The upper part of Figure 2 shows the structure of the infrastructure BSS (basic service set) of IEEE (institute of electrical and electronic engineers) 802.11.

[0072] Referring to the top of FIG. 2, the wireless LAN system may include one or more infrastructure BSSs (200, 205) (hereinafter, BSS). The BSSs (200, 205) are a collection of APs and STAs, such as an access point (AP) 225 and a station (STA1, 200-1), that have successfully synchronized and can communicate with each other, and are not a concept that designates a specific area. The BSS (205) may also include one or more STAs (205-1, 205-2) that can be associated with one AP (230).

[0073] A BSS may include at least one STA, an AP (225, 230) providing a distribution service, and a distribution system (DS, 210) connecting multiple APs.

[0074] A distributed system (210) can connect multiple BSSs (200, 205) to implement an extended service set (ESS, 240). An ESS (240) can be used as a term to indicate a network formed by connecting one or more APs through the distributed system (210). APs included in a single ESS (240) can have the same SSID (service set identification).

[0075] The portal (portal, 220) can act as a bridge to connect a wireless LAN network (IEEE 802.11) to another network (e.g., 802.X).

[0076] In a BSS such as the upper part of Fig. 2, a network between APs (225, 230) and a network between APs (225, 230) and STAs (200-1, 205-1, 205-2) can be implemented. However, it may also be possible to establish a network and perform communication between STAs without an AP (225, 230). A network that establishes a network and performs communication between STAs without an AP (225, 230) is defined as an ad-hoc network or an independent basic service set (IBSS).

[0077] The bottom of Figure 2 is a conceptual diagram showing IBSS.

[0078] Referring to the bottom of Fig. 2, the IBSS is a BSS that operates in ad-hoc mode. Since the IBSS does not include an AP, there is no centralized management entity. That is, in the IBSS, the STAs (250-1, 250-2, 250-3, 255-4, 255-5) are managed in a distributed manner. In the IBSS, all STAs (250-1, 250-2, 250-3, 255-4, 255-5) can be mobile STAs, and access to the distributed system is not permitted, forming a self-contained network.

[0079] Figure 3 is a diagram illustrating a general link setup process.

[0080] In step S310, the STA may perform a network discovery operation. This network discovery operation may include scanning by the STA. That is, for the STA to access the network, it must find a network it can join. Before joining a wireless network, the STA must identify compatible networks. The process of identifying networks in a specific area is called scanning. Scanning methods include active scanning and passive scanning.

[0081] Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, an STA performing scanning transmits a probe request frame to discover which APs exist in the vicinity while moving between channels and waits for a response. A responder transmits a probe response frame to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In a BSS, the AP transmits the beacon frame, so the AP becomes the responder. In an IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not constant. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning (i.e., transmitting and receiving probe requests / responses on channel 2) in the same manner.

[0082] Although not shown in the example of FIG. 3, the scanning operation can also be performed in a passive scanning manner. An STA performing scanning based on passive scanning can wait for a beacon frame while moving between channels. A beacon frame is one of the management frames in IEEE 802.11. It announces the presence of a wireless network and is periodically transmitted so that the scanning STA can find the wireless network and participate in the wireless network. In the BSS, the AP periodically transmits the beacon frame, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the scanning STA receives a beacon frame, it stores the information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. An STA that receives a beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning on the next channel in the same manner.

[0083] An STA that discovers a network can perform an authentication process through step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation of step S340 described below. The authentication process of S320 may include a process in which the STA transmits an authentication request frame to the AP, and the AP responds by transmitting an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0084] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), and a Finite Cyclic Group.

[0085] An STA can transmit an authentication request frame to an AP. The AP can determine whether to grant authentication to the STA based on the information contained in the received authentication request frame. The AP can provide the result of the authentication process to the STA via an authentication response frame.

[0086] A successfully authenticated STA may perform an association process based on step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and the AP transmits an association response frame to the STA in response. For example, the association request frame may include information related to various capabilities, such as a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, and interworking service capabilities. For example, the association response frame may contain information related to various capabilities, status codes, Association ID (AID), supported rates, Enhanced Distributed Channel Access (EDCA) parameter sets, Received Channel Power Indicator (RCPI), Received Signal to Noise Indicator (RSNI), mobility domains, timeout interval (association comeback time), overlapping BSS scan parameters, TIM broadcast response, QoS maps, etc.

[0087] In step S340, the STA may perform a security setup process. The security setup process of step S340 may include, for example, a process of setting up a private key through a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame.

[0088] Figure 4 illustrates one embodiment of a multi-link (ML).

[0089] As illustrated in FIG. 4, multiple multi-link devices (MLDs) can communicate over a remote link. The MLDs can be categorized into AP MLDs including multiple AP STAs and non-AP MLDs including multiple non-AP STAs. That is, the AP MLD can include affiliated APs (i.e., AP STAs), and the non-AP MLD can include affiliated STAs (i.e., non-AP STAs, or user-STAs).

[0090] A multilink may include a first link and a second link, and different channels / subchannels / frequency resources may be allocated to the first and second links. The first and second multilinks may be identified through a link ID of 4 bits (or other n bits). The first and second links may be configured in the same 2.4 GHz, 5 GHz, or 6 GHz band. Alternatively, the first link and the second link may be configured in different bands.

[0091] The AP MLD of FIG. 4 includes three affiliated APs. In the example of FIG. 4, AP1 may operate in the 2.4 GHz band, AP2 may operate in the 5 GHz band, and AP3 may operate in the 6 GHz band. In the example of FIG. 4, the first link in which AP1 and non-AP1 operate may be defined as a channel / subchannel / frequency resource within the 2.4 GHz band. Furthermore, in the example of FIG. 4, the second link in which AP2 and non-AP2 operate may be defined as a channel / subchannel / frequency resource within the 5 GHz band. Furthermore, in the example of FIG. 4, the third link in which AP3 and non-AP3 operate may be defined as a channel / subchannel / frequency resource within the 6 GHz band.

[0092] In the example of FIG. 4, AP1 may initiate a multi-link setup procedure (ML setup procedure) by transmitting an Association Request frame to non-AP STA1. In the example of FIG. 4, non-AP STA1 may transmit an Association Response frame in response to the Association Request frame. Each AP (e.g., AP1 / 2 / 3) illustrated in FIG. 4 may be identical to the AP illustrated in FIG. 1 and / or FIG. 2, and each non-AP (e.g., non-AP1 / 2 / 3) illustrated in FIG. 4 may be identical to the STA (i.e., user-STA or non-AP STA) illustrated in FIG. 1 and / or FIG. 2.

[0093] The specific features of this specification are not limited to the specific features of FIG. 4. That is, the number of links can be defined in various ways, and multiple links can be defined in various ways within at least one band.

[0094] FIG. 5 illustrates a PPDU (physical protocol data unit or physical layer (PHY) protocol data unit) transmitted / received by an STA of this specification.

[0095] The STA (e.g., AP STA, non-AP STA, AP MLD, non-AP MLD) of the present specification can transmit and / or receive the PPDU of FIG. 5. The PPDU described in the present specification may have, for example, the structure of FIG. 5. In addition, the PPDU described in the present specification may be called by various names such as a transmission PPDU, a reception PPDU, a first type PPDU, or an Nth type PPDU, etc. The PPDU described in the present specification can be used in a WLAN system defined according to IEEE 802.11bn and / or a next-generation WLAN system that improves IEEE 802.11bn.

[0096] The PPDU of FIG. 5 may be related to various PPDU types used in a UHR system. For example, the example of FIG. 5 may be used for at least one of a single-user (SU) mode / type / transmission, a multi-user (MU) mode / type / transmission, and a null data packet (NDP) mode / type / transmission related to channel sounding. For example, if the example of FIG. 5 is related to NDP, the Data field illustrated may be omitted. If the PPDU of FIG. 5 is used for a trigger-based (TB) mode, the UHR-SIG of FIG. 5 may be omitted. In other words, an STA that has received a trigger frame for UL-MU (Uplink-MU) communication may transmit a PPDU with the UHR-SIG omitted in the example of FIG. 5.

[0097] In FIG. 5, L-STF or UHR-LTF may be called a preamble or physical preamble, and may be generated / transmitted / received / acquired / decoded in the physical layer (included in the transmitting / receiving STA).

[0098] Each block illustrated in Fig. 5 may be called a field / subfield / signal, etc. The names of these fields / subfields / signals may be, as illustrated in Fig. 5, L-STF (legacy short training field), L-LTF (legacy long training field), L-SIG (legacy signal), RL-SIG (repeated L-SIG), U-SIG (Universal Signal), UHR-SIG (UHR-signal), etc.

[0099] The subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG fields in FIG. 5 may be set to 312.5 kHz, and the subcarrier spacing of the UHR-STF, UHR-LTF, and Data fields may be set to 78.125 kHz. That is, the tone index (or subcarrier index) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG fields may be expressed in units of 312.5 kHz, and the tone index (or subcarrier index) of the UHR-STF, UHR-LTF, and Data fields may be expressed in units of 78.125 kHz.

[0100] In the PPDU of Fig. 5, L-LTF and L-STF may be identical to conventional fields (e.g., non-HT LTF and non-HT STF defined in conventional WLAN standards).

[0101] The L-SIG field of FIG. 5 may include, for example, 24 bits of bit information. For example, the 24 bits of information may include a 4 bit Rate field, a 1 bit Reserved bit, a 12 bit Length field, a 1 bit Parity bit, and a 6 bit Tail bit. For example, the 12 bit Length field may include information about the length or time duration of the PPDU. For example, the value of the 12 bit Length field may be determined based on the type of the PPDU. For example, if the PPDU is a non-HT (non-High Throughput), HT (High Throughput), VHT (Very High Throughput) PPDU, or an EHT (extremely high throughput) PPDU or UHR PPDU, the value of the Length field may be determined as a multiple of 3. For example, if the PPDU is a HE PPDU, the value of the Length field may be determined as "a multiple of 3 + 1" or "a multiple of 3 + 2". In other words, for non-HT, HT, VHT PPDU, EHT PPDU, UHR PPDU, the value of the Length field can be determined as a multiple of 3, and for HE (High-Efficiency) PPDU, the value of the Length field can be determined as "a multiple of 3 + 1" or "a multiple of 3 + 2". In other words, the Length field in an UHR PPDU is set to a value satisfying the condition that the remainder is zero when LENGTH is divided by 3.

[0102] For example, (non-AP and AP) STAs can apply BCC encoding based on a code rate of 1 / 2 to the 24 bits of information in the L-SIG field. Then, the transmitting STA can obtain 48 BCC coded bits. BPSK modulation can be applied to the 48 coded bits to generate 48 BPSK symbols. The transmitting STA can map the 48 BPSK symbols to positions excluding the pilot subcarriers {subcarrier index -21, -7, +7, +21} and the DC subcarrier {subcarrier index 0}. As a result, the 48 BPSK symbols can be mapped to subcarrier indices -26 to -22, -20 to -8, -6 to -1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA can additionally map the signal {-1, -1, -1, 1} to the subcarrier indices {-28, -27, +27, +28}. The above signal can be used for channel estimation for the frequency domain corresponding to {-28, -27, +27, +28}.

[0103] For example, (non-AP and AP) STA can generate RL-SIG, which is generated in the same manner as L-SIG. BPSK modulation can be applied to RL-SIG. Receiving (non-AP and AP) STA can determine whether the received PPDU is a HE PPDU, EHT PPDU, or UHR PPDU based on the presence of RL-SIG. In other words, if RL-SIG is present, receiving (non-AP and AP) STA can determine whether the received PPDU is one of HE PPDU, EHT PPDU, or UHR PPDU. In other words, if RL-SIG is not present, receiving (non-AP and AP) STA can determine whether the received PPDU is one of non-HT PPDU, HT PPDU, or VHT PPDU. In other words, the RL-SIG field is a repeat of the L-SIG field and is used to differentiate an UHR PPDU from a non-HT PPDU, HT PPDU, and VHT PPDU.

[0104] After the RL-SIG in Fig. 5, a U-SIG (Universal SIG) may be inserted. The U-SIG may be called by various names such as the first SIG field, the first SIG, the first type SIG, the control signal, the control signal field, the first (type) control signal, the common control field, and the common control signal.

[0105] A U-SIG can contain N bits of information and can include information for identifying the type of EHT PPDU. For example, a U-SIG can be formed based on two symbols (e.g., two consecutive OFDM symbols). Each symbol for a U-SIG (e.g., an OFDM symbol) can have a duration of 4 microseconds. Each symbol of a U-SIG can be used to transmit 26 bits of information. For example, each symbol of a U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0106] For example, A bit information (e.g., 52 uncoded bits) can be transmitted through U-SIG, and the first symbol of U-SIG can transmit the first X bits of information (e.g., 26 uncoded bits) out of the total A bit information, and the second symbol of U-SIG can transmit the remaining Y bits of information (e.g., 26 uncoded bits) out of the total A bit information. For example, the transmitting STA can obtain 26 uncoded bits included in each U-SIG symbol. The transmitting STA can perform convolutional encoding (i.e., BCC encoding) based on a rate of R=1 / 2 to generate 52 coded bits, and perform interleaving on the 52 coded bits. The transmitting STA can perform BPSK modulation on the interleaved 52 coded bits to generate 52 BPSK symbols allocated to each U-SIG symbol. A single U-SIG symbol can be transmitted based on 56 tones (subcarriers) from subcarrier index -28 to subcarrier index +28, excluding DC index 0. The 52 BPSK symbols generated by the transmitting STA can be transmitted based on the remaining tones (subcarriers) excluding the pilot tones -21, -7, +7, and +21.

[0107] For example, A bit information (e.g., 52 uncoded bits) transmitted by U-SIG may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). The CRC field and the tail field may be transmitted through the second symbol of the U-SIG. The CRC field may be generated based on 26 bits allocated to the first symbol of the U-SIG and the remaining 16 bits excluding the CRC / tail field within the second symbol, and may be generated based on a conventional CRC calculation algorithm. In addition, the tail field may be used to terminate the trellis of the convolutional decoder and may be set to, for example, "000000".

[0108] The A bit information (e.g., 52 uncoded bits) transmitted by the U-SIG (or U-SIG field) can be divided into version-independent bits and version-dependent bits. For example, the size of the version-independent bits can be fixed or variable. For example, the version-independent bits can be assigned only to the first symbol of the U-SIG, or the version-independent bits can be assigned to both the first symbol and the second symbol of the U-SIG. For example, the version-independent bits and the version-dependent bits can be called by various names, such as the first control bit and the second control bit.

[0109] For example, the version-independent bits of the U-SIG may include a 3-bit PHY version identifier. For example, the 3-bit PHY version identifier may include information related to the PHY version of the transmitted and received PPDU. For example, a first value (e.g., a value of 000) of the 3-bit PHY version identifier may indicate that the transmitted and received PPDU is an EHT PPDU. In addition, a second value (e.g., a value of 001) of the 3-bit PHY version identifier may indicate that the transmitted and received PPDU is an UHR PPDU.

[0110] In other words, when the (AP / non-AP) STA transmits an EHT PPDU, it can set the 3-bit PHY version identifier to the first value. In other words, the receiving (AP / non-AP) STA can determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value, and can determine that the received PPDU is an UHR PPDU based on the PHY version identifier having the second value.

[0111] For example, 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.

[0112] For example, the version-independent bits of U-SIG may include information about the length of a transmission opportunity (TXOP) and information about the BSS color ID.

[0113] For example, if a UHR PPDU is classified into various types (e.g., a type related to SU transmission (performed based on UL or DL), a type related to DL transmission, a type related to NDP transmission, a type related to DL non-MU-MIMO, a type related to DL MU-MIMO, a type related to Multi-AP operation, a type related to CBF (Coordinated beamforming), SR (Spatial Reuse), a type related to C-OFDMA (Coordinated OFDMA), a type related to C-TDMA (Coordinated TDMA)), information about the type of the EHT PPDU (e.g., 2-bit or 3-bit information) can be included in the version-dependent bits of the U-SIG.

[0114] For example, a U-SIG may include information about 1) a bandwidth field including information about a bandwidth, 2) a field including information about an MCS technique applied to the UHR-SIG, 3) an indication field including information about whether a dual subcarrier modulation (DCM) technique is applied to the UHR-SIG, 4) a field including information about the number of symbols used for the UHR-SIG, 5) a field including information about whether the UHR-SIG is generated over the entire band, 6) a field including information about the type of UHR-LTF / STF, and 7) a field indicating the length of the UHR-LTF and the CP length.

[0115] Preamble puncturing may be applied to the PPDU of FIG. 5. Preamble puncturing refers to applying puncturing to a portion of the entire bandwidth of the PPDU (e.g., the secondary 20 MHz band). For example, when an 80 MHz PPDU is transmitted, the STA applies puncturing to the secondary 20 MHz band within the 80 MHz band, and can transmit the PPDU only through the primary 20 MHz band and the secondary 40 MHz band.

[0116] For example, the pattern of preamble puncturing can be preset. For example, when the first puncturing pattern is applied, puncturing can be applied only to the secondary 20 MHz band within the 80 MHz band. For example, when the second puncturing pattern is applied, puncturing can be applied only to one of the two secondary 20 MHz bands included in the secondary 40 MHz band within the 80 MHz band. For example, when the third puncturing pattern is applied, puncturing can be applied only to the secondary 20 MHz band included in the primary 80 MHz band within the 160 MHz band (or 80+80 MHz band). For example, when the fourth puncturing pattern is applied, a primary 40 MHz band included in the primary 80 MHz band within the 160 MHz band (or 80+80 MHz band) may be present, and puncturing may be applied to at least one 20 MHz channel that does not belong to the primary 40 MHz band.

[0117] Information regarding preamble puncturing applied to the PPDU may be included in the U-SIG and / or UHR-SIG. For example, the first field of the U-SIG may include information regarding the contiguous bandwidth of the PPDU, and the second field of the U-SIG may include information regarding preamble puncturing applied to the PPDU.

[0118] For example, U-SIG and UHR-SIG may include information regarding preamble puncturing based on the following method. If the bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be individually configured in units of 80 MHz. For example, if the bandwidth of the PPDU is 160 MHz, the PPDU may include a first U-SIG for the first 80 MHz band and a second U-SIG for the second 80 MHz band. In this case, the first field of the first U-SIG may include information regarding the 160 MHz bandwidth, and the second field of the first U-SIG may include information regarding preamble puncturing applied to the first 80 MHz band (i.e., information regarding the preamble puncturing pattern). Additionally, the first field of the second U-SIG may include information about a 160 MHz bandwidth, and the second field of the second U-SIG may include information about preamble puncturing applied to the second 80 MHz band (i.e., information about a preamble puncturing pattern). Meanwhile, the UHR-SIG consecutive to the first U-SIG may include information about preamble puncturing applied to the second 80 MHz band (i.e., information about a preamble puncturing pattern), and the UHR-SIG consecutive to the second U-SIG may include information about preamble puncturing applied to the first 80 MHz band (i.e., information about a preamble puncturing pattern).

[0119] Additionally or alternatively, U-SIG and UHR-SIG may include information regarding preamble puncturing based on the following methods. U-SIG may include information regarding preamble puncturing for all bands (i.e., information regarding preamble puncturing patterns). That is, UHR-SIG may not include information regarding preamble puncturing, and only U-SIG may include information regarding preamble puncturing (i.e., information regarding preamble puncturing patterns).

[0120] U-SIGs can be configured in 20 MHz units. For example, if an 80 MHz PPDU is configured, U-SIGs can be duplicated. That is, four identical U-SIGs can be included within an 80 MHz PPDU. PPDUs exceeding the 80 MHz bandwidth can contain different U-SIGs.

[0121] The UHR-SIG of FIG. 5 may include control information for a receiving STA. The UHR-SIG may be transmitted via at least one symbol, and each symbol may have a length of 4 us. Information regarding the number of symbols used for the UHR-SIG may be included in the U-SIG.

[0122] UHR-SIG provides additional signals to the U-SIG field to enable STAs to interpret / decode UHR PPDUs. The UHR-SIG field may contain U-SIG overflow bits that are common to all users. The UHR-SIG field also contains resource allocation information, allowing STAs to look up resources used in fields containing data fields / UHR-STF / UHR-LTF (i.e., UHR modulated fields of an UHR PPDU).

[0123] The frequency resources of the UHR-LTF, UHR-STF, and data fields illustrated in FIG. 5 can be determined based on RUs (resource units) defined by multiple subcarriers / tones. That is, the UHR-LTF, UHR-STF, and data fields of this specification can be transmitted / received through RUs (resource units) defined by multiple subcarriers / tones.

[0124] FIG. 6 is a diagram illustrating the layout of resource units (RUs) used for a 20 MHz PPDU. That is, the UHR-LTF, UHR-STF, and / or data fields included in the 20 MHz PPDU can be transmitted / received through at least one of the various RUs defined in FIG. 6.

[0125] As shown at the top of Fig. 6, 26 units (i.e., units corresponding to 26 tones) can be arranged. Six tones can be used as a guard band in the leftmost band of the 20 MHz band, and five tones can be used as a guard band in the rightmost band of the 20 MHz band. In addition, seven DC tones can be inserted in the center band, i.e., the DC band, and 26 units corresponding to 13 tones can exist on each side of the DC band. In addition, 26 units, 52 units, and 106 units can be allocated to other bands. Each unit can be allocated for a receiving station, i.e., a user.

[0126] Meanwhile, the RU arrangement of FIG. 6 is utilized not only in a situation for multiple users (MUs) but also in a situation for a single user (SU), in which case it is possible to use one 242-unit as shown at the bottom of FIG. 4, in which case three DC tones can be inserted.

[0127] In the example of Fig. 6, RUs of various sizes, such as 26-RU, 52-RU, 106-RU, and 242-RU, are proposed. Since the specific sizes of these RUs can be expanded or increased, the present embodiment is not limited to the specific size of each RU (i.e., the number of corresponding tones). In this specification, N-RU may be represented as N-tone RU, etc. For example, 26-RU may be represented as 26-tone RU.

[0128] Figure 7 is a diagram showing the layout of resource units (RUs) used for 40MHz PPDU.

[0129] As in the example of Fig. 6 where RUs of various sizes were used, the example of Fig. 7 can also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. In addition, 5 DC tones can be inserted at the center frequency, 12 tones can be used as a guard band in the leftmost band of the 40 MHz band, and 11 tones can be used as a guard band in the rightmost band of the 40 MHz band.

[0130] Additionally, as illustrated, 484 RUs may be used when used for a single user. Meanwhile, the specific number of RUs may be changed, as in the example of FIG. 6.

[0131] Figure 8 is a diagram illustrating the layout of resource units (RUs) used for an 80MHz PPDU. The layout of resource units (RUs) used in this specification may vary. For example, the layout of resource units (RUs) used in the 80MHz band may vary.

[0132] Figure 9 illustrates an operation according to UL-MU. As illustrated, a transmitting STA (e.g., AP) can perform channel access through contending (i.e., backoff operation) and transmit a trigger frame (930). That is, the transmitting STA (e.g., AP) can transmit a PPDU including a trigger frame (930). When a PPDU including a trigger frame is received, a TB (trigger-based) PPDU is transmitted after a delay of SIFS.

[0133] TB PPDUs (941, 942) are transmitted at the same time and can be transmitted from multiple STAs (e.g., User STAs) whose AIDs are indicated in the Trigger frame (930). The ACK frame (950) for the TB PPDU can be implemented in various forms.

[0134] Figure 10 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0135] The 2.4 GHz band may be referred to by other names, such as the first band (band). Furthermore, the 2.4 GHz band may refer to a frequency range in which channels with a center frequency adjacent to 2.4 GHz (e.g., channels with a center frequency between 2.4 and 2.5 GHz) are used / supported / defined.

[0136] The 2.4 GHz band may include multiple 20 MHz channels. The 20 MHz within the 2.4 GHz band may have multiple channel indices (e.g., indices 1 through 14). For example, the center frequency of a 20 MHz channel assigned channel index 1 may be 2.412 GHz, the center frequency of a 20 MHz channel assigned channel index 2 may be 2.417 GHz, and the center frequency of a 20 MHz channel assigned channel index N may be (2.407 + 0.005*N) GHz. The channel indices may be referred to by various names, such as channel numbers. The specific numerical values ​​of the channel indices and center frequencies may change.

[0137] Figure 10 exemplarily illustrates four channels within the 2.4 GHz band. The illustrated first frequency region (1010) to fourth frequency region (1040) may each include one channel. For example, the first frequency region (1010) may include channel 1 (a 20 MHz channel having an index of 1). In this case, the center frequency of channel 1 may be set to 2412 MHz. The second frequency region (1020) may include channel 6. In this case, the center frequency of channel 6 may be set to 2437 MHz. The third frequency region (1030) may include channel 11. In this case, the center frequency of channel 11 may be set to 2462 MHz. The fourth frequency region (1040) may include channel 14. In this case, the center frequency of channel 14 may be set to 2484 MHz.

[0138] Figure 11 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0139] The 5 GHz band may be referred to by other names, such as a second band / band, etc. The 5 GHz band may refer to a frequency range in which channels with center frequencies greater than or equal to 5 GHz and less than 6 GHz (or less than 5.9 GHz) are used / supported / defined. Alternatively, the 5 GHz band may include multiple channels between 4.5 GHz and 5.5 GHz. The specific figures shown in FIG. 11 are subject to change.

[0140] Multiple channels within the 5 GHz band include Unlicensed National Information Infrastructure (UNII)-1, UNII-2, UNII-3, and ISM. UNII-1 may be referred to as UNII Low. UNII-2 may include frequency ranges called UNII Mid and UNII-2Extended. UNII-3 may be referred to as UNII-Upper.

[0141] Within the 5 GHz band, multiple channels can be configured, and the bandwidth of each channel can be variously configured, such as 20 MHz, 40 MHz, 80 MHz, or 160 MHz. For example, the 5170 MHz to 5330 MHz frequency domain / range within UNII-1 and UNII-2 can be divided into eight 20 MHz channels. The 5170 MHz to 5330 MHz frequency domain / range can be divided into four channels through a 40 MHz frequency domain. The 5170 MHz to 5330 MHz frequency domain / range can be divided into two channels through an 80 MHz frequency domain. Alternatively, the 5170 MHz to 5330 MHz frequency domain / range can be divided into one channel through a 160 MHz frequency domain.

[0142] Figure 12 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0143] The 6 GHz band may also be referred to by other names, such as the third band / band. The 6 GHz band may refer to the frequency range in which channels with center frequencies above 5.9 GHz are used, supported, or defined. The specific figures shown in Figure 12 are subject to change.

[0144] For example, the 20 MHz channel of FIG. 12 can be defined from 5.940 GHz. Specifically, the leftmost channel among the 20 MHz channels of FIG. 12 can have an index of 1 (or channel index, channel number, etc.), and a center frequency of 5.945 GHz can be assigned. That is, the center frequency of the indexed channel N can be determined as (5.940 + 0.005*N) GHz.

[0145] Accordingly, the indexes (or channel numbers) of the 20 MHz channels of FIG. 12 are 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 129, 133, 137, 141, 145, 149, 153, 157, 161, 165, 169, 173, 177, 181, 185, 189, 193, It can be 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. Also, according to the (5.940 + 0.005*N) GHz rule mentioned above, the indices of the 40 MHz channels in Fig. 12 can be 3, 11, 19, 27, 35, 43, 51, 59, 67, 75, 83, 91, 99, 107, 115, 123, 131, 139, 147, 155, 163, 171, 179, 187, 195, 203, 211, 219, 227.

[0146] Below, the structure and types / subtypes of MAC frames are described.

[0147] Fig. 13 illustrates an example of a header of a MAC frame. As illustrated, the MAC frame may include a frame control field / information of 2 octets in length, a duration field / information of 2 octets in length, a RA (Receiver Address) field / information of 6 octets in length, and a TA (Transmitter Address) field / information of 6 octets in length. As illustrated in Fig. 13, the four fields may be consecutive to each other. The MAC header of Fig. 13 may be modified in various ways, and a new field may be inserted between the four illustrated fields, or at least one of the illustrated fields may be omitted.

[0148] The MAC header illustrated in Fig. 13 may be located at the very front of the MAC frame. That is, the MAC frame may include a MAC header as illustrated in Fig. 13 and MAC body fields / information consecutive to the MAC header. The MAC frame including the MAC header of Fig. 13 is inserted / included in the data field of the PPDU (e.g., UHR PPDU) illustrated in Fig. 5.

[0149] The MAC frames included in the data field of the PPDU of this specification can be classified into various types. For example, the MAC frames of this specification can be classified into control frames, management frames, and data frames.

[0150] For example, the management frame includes Association Request, Association Response, Reassociation Request, Reassociation Response, Probe Request, Probe Response, Beacon, Disassociation, Authentication, and Deauthentication frames / signals defined in conventional WLAN. For the management frame, the values ​​of the type fields (B3 and B2) in FIG. 13 are set to 00. In addition, the values ​​of the subtype fields (B7, B6, B5, B4) in FIG. 13 are as follows: Association Request (0000), Association Response (0001), Reassociation Request (0010), Reassociation Response (0011), Probe Request (0100), Probe Response (0101), Beacon (1000), Disassociation (1010), Authentication (1011), Deauthentication (1100).

[0151] For example, the control frame includes Trigger Beamforming Report Poll, NDP Announcement (NDPA), Control Frame Extension, Control Wrapper, Block Ack Request (BlockAckReq), Block Ack (BlockAck), PS-Poll, RTS, CTS, Ack, and CF-End frames / signals defined in conventional WLAN. For the control frame, the value of the type field (B3 and B2) in FIG. 13 is set to 01. Also, the values ​​of the subtype fields (B7, B6, B5, B4) of FIG. 13 are as follows: Trigger (0010), Beamforming Report Poll (0100), NDP Announcement (0101), Control Frame Extension (0110), Control Wrapper (0111), BlockAckReq (1000), BlockAck (1001), PS-Poll (1010), RTS (1011), CTS (1100), Ack (1101), CF-End (1110).

[0152] For example, the data frame includes (QoS) Data, (QoS) Null, etc. defined in conventional WLAN. For the management frame, the value of the type field (B3 and B2) of Fig. 13 is set to 10.

[0153] The MAC frame / signal used in this specification can be identified through the type field / information and subtype field / information described above. For example, “frame” in this specification can mean a MAC frame in which the type bits B3 and B2 bits in the frame control field of the MAC header are set to 01, and the subtype bits B7, B6, B5, and B4 bits in the frame control field are set to 0010. Various MAC frames described in this specification are inserted / included in the data fields of various PPDUs (e.g., HE / VHT / HE / EHT / UHR PPDUs).

[0154] FIG. 14 illustrates a modified example of a transmitting device and / or a receiving device of the present specification.

[0155] The devices (e.g., AP STA, non-AP STA) illustrated in FIGS. 1 to 4 may be modified as illustrated in FIG. 14. The transceiver (630) of FIG. 14 may be identical to the transceivers (113, 123) of FIG. 1. The transceiver (630) of FIG. 14 may include a receiver and a transmitter.

[0156] The processor (610) of FIG. 14 may be identical to the processor (111, 121) of FIG. 1. Alternatively, the processor (610) of FIG. 14 may be identical to the processing chip (114, 124) of FIG. 1.

[0157] The memory (150) of FIG. 14 may be the same as the memory (112, 122) of FIG. 1. Alternatively, the memory (150) of FIG. 14 may be a separate external memory different from the memory (112, 122) of FIG. 1.

[0158] Referring to FIG. 14, a power management module (611) manages power to a processor (610) and / or a transceiver (630). A battery (612) supplies power to the power management module (611). A display (613) outputs results processed by the processor (610). A keypad (614) receives input to be used by the processor (610). The keypad (614) may be displayed on the display (613). A SIM card (615) may be an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and an associated key used to identify and authenticate a subscriber in a mobile phone device, such as a mobile phone or computer.

[0159] Referring to FIG. 14, the speaker (640) can output sound-related results processed by the processor (610). The microphone (641) can receive sound-related input to be used by the processor (610).

[0160] 1. EHT sounding protocol

[0161] Transmit beamforming and Downlink Multi-User-Multi-Input-Multi-Output (DL MU-MIMO) require knowledge of the channel conditions to compute a steering matrix applied to the transmitted signal to optimize reception at one or more receivers. The EHT STA determines the channel condition information using the EHT sounding protocol. The EHT sounding protocol provides an explicit feedback mechanism, defined as EHT non-trigger-based (non-TB) sounding and EHT trigger-based (TB) sounding. Here, the EHT beamformee measures the channel using training signals transmitted by the EHT beamformer (i.e., the EHT sounding NDP) and sends back a transformed estimate of the channel condition. The EHT beamformer uses this estimate to derive the steering matrix.

[0162] EHT Beamformer returns an estimate of the channel state from an EHT compressed Beamforming / CQI report contained in one or more EHT Compressed Beamforming / CQI frames. There are three types of EHT compressed Beamforming / CQI reports.

[0163] - SU Feedback: EHT Compression Beamforming / CQI report consists of EHT Compression Beamforming report field.

[0164] - MU Feedback: The EHT Compressed Beamforming / CQI report consists of an EHT Compressed Beamforming report field and an EHT MU Exclusive Beamforming report field.

[0165] - CQI Feedback: EHT Compression Beamforming / CQI Reporting consists of an EHT CQI Reporting field.

[0166] Note that the use of EHT TB sounding does not necessarily imply MU feedback. EHT TB sounding is also used to obtain SU feedback and CQI feedback.

[0167] Figure 15 shows an example of EHT non-TB sounding.

[0168] The EHT non-TB sounding sequence is initiated by the EHT beamformer using an individually addressed EHT NDP Announcement frame containing exactly one STA information field, followed by an SIFS followed by the EHT sounding NDP. The EHT beamformer responds with an EHT Compressed Beamforming / CQI frame after an SIFS.

[0169] The AID11 subfield of the STA Information field shall be set to the AID of the STA identified by the RA field of the EHT NDP Announcement frame, or shall be set to 0 if the STA identified by the RA field is a mesh STA, AP, or IBSS STA.

[0170] An example of an EHT non-TB sounding sequence with a single EHT beamformer is shown in Fig. 12.

[0171] Figure 16 shows an example of EHT TB sounding.

[0172] An EHT TB sounding sequence is initiated by an EHT beamformer using a broadcast EHT NDP Announcement frame with two or more STA information fields, followed by an SIFS followed by an EHT sounding NDP, and followed by an SIFS followed by a Beamforming Report Poll (BFRP) trigger frame. Each EHT beamformee responds after an SIFS with an EHT TB PPDU containing one or more EHT Compressed Beamforming / CQI frames. A BFRP trigger frame transmitted within an EHT TB sounding sequence must request an EHT TB PPDU.

[0173] An example of an EHT TB sounding sequence with two or more EHT beamformers is shown in FIG. 13.

[0174] An EHT beamformer initiating an EHT TB sounding sequence must transmit an EHT NDP Announcement frame containing two or more STA information fields and the RA field set to the broadcast address.

[0175] The EHT beamformer may initiate an EHT TB sounding sequence to request SU, MU, or CQI feedback.

[0176] Figure 17 shows an example of the EHT NDP Announcement frame format.

[0177] The VHT / HE / EHT NDP Announcement frame has three variants: the VHT NDP Announcement frame, the HE NDP Announcement frame, and the EHT NDP Announcement frame. Each variant is distinguished by the configuration of the HE subfield and the Ranging subfield within the Sounding Dialog Token field.

[0178] The VHT / HE / EHT NDP Announcement frame contains at least one STA Info field. If the VHT / HE / EHT NDP Announcement frame contains only one STA Info field, the RA field is set to the address of an STA that can provide feedback. If the VHT / HE / EHT NDP Announcement frame contains more than one STA Info field, the RA field is set to the broadcast address.

[0179] The TA field is set to the address of the STA transmitting the VHT / HE / EHT NDP Announcement frame or the bandwidth signaling TA of the STA transmitting the VHT / HE / EHT NDP Announcement frame.

[0180] The Resolution subfield of the Partial BW Info subfield indicates the resolution bandwidth for each bit of the Feedback Bitmap subfield. The Feedback Bitmap subfield indicates the request for each resolution bandwidth from the lowest frequency to the highest frequency, with B1 indicating the lowest resolution bandwidth. Each bit of the Feedback Bitmap subfield is set to 1 if feedback is requested for the corresponding resolution bandwidth.

[0181] The Partial BW Info subfield is defined in the format at the bottom of Figure 14. The Resolution bit indicates the feedback resolution bandwidth. The Resolution bit is set to 0 to indicate a resolution of 20 MHz when the BW subfield is set to 0 to 3, and is set to 1 to indicate a resolution of 40 MHz when the BW subfield is set to 4. The Feedback Bitmap subfield indicates each resolution bandwidth for which the beamformer requests feedback. Each bit in the Feedback Bitmap subfield is set to 1 if feedback is requested for the corresponding bandwidth, and 0 otherwise.

[0182] If the bandwidth of the EHT NDP Announcement frame is less than 320 MHz, the Resolution bit B0 is set to 0 to indicate a resolution of 20 MHz.

[0183] - When the bandwidth of the EHT NDP Announcement frame is 20 MHz, B1 is set to 1 to indicate a feedback request for a 242-tone RU. B2-B8 are reserved and set to 0.

[0184] - When the bandwidth of the EHT NDP Announcement frame is 40 MHz, B1 and B2 indicate feedback requests for each of the two 242-tone RUs, from low to high frequency. B3-B8 are reserved and set to 0.

[0185] - When the bandwidth of the EHT NDP Announcement frame is 80 MHz, B1 to B4 represent feedback requests for each of the four 242-tone RUs, from low frequency to high frequency. B5 to B8 are reserved and set to 0. If B1 to B4 are all set to 1, it represents a feedback request for the 996-tone RU.

[0186] - When the bandwidth of the EHT NDP Announcement frame is 160 MHz, B1-B8 represent feedback requests for each of the eight 242-tone RUs from low to high frequency. If B1-B4 are all set to 1, it represents a feedback request for the lower 996-tone RU, and if B5-B8 are all set to 1, it represents a feedback request for the upper 996-tone RU.

[0187] When the bandwidth of the EHT NDP Announcement frame is 320 MHz, the Resolution bit B0 is set to 1 to indicate a resolution of 40 MHz. B1 through B8 represent feedback requests for each of the eight 484-tone RUs from low to high frequency. When B1 and B2 are both set to 1, it represents a feedback request for the lowest 996-tone RU, when B3 and B4 are both set to 1, it represents a feedback request for the second-lowest 996-tone RU, when B5 and B6 are both set to 1, it represents a feedback request for the second-highest 996-tone RU, and when B7 and B8 are both set to 1, it represents a feedback request for the highest 996-tone RU.

[0188] The Feedback Type And Ng subfield and the Codebook Size subfield are defined as follows:

[0189] Feedback Type And NgCodebook SizeDescriptionB25B26B28000SU, Ng = 4, quantization resolution (phi, psi) = {4, 2}001SU, Ng = 4, quantization resolution (phi, psi) = {6, 4}010SU, Ng = 16, quantization resolution (phi, psi) = {4, 2}011SU, Ng = 16, quantization resolution (phi, psi) = {6, 4}100MU, Ng = 4, quantization resolution (phi, psi) = {7, 5}101MU, Ng = 4, quantization resolution (phi, psi) = {9, 7}110CQI111MU, Ng = 16, quantization resolution (phi, psi) = {9, 7}

[0190] EHT CQI feedback is as follows. When a beamformer requests CQI feedback via an EHT NDPA frame, the beamformee computes CQI feedback for all RUs indicated by the EHT NDPA frame, where CQI feedback (CQI s,r,u) is computed for beamformee u in RU r for spatial stream s. The EHT CQI Report field conveys the average signal-to-noise ratio (SNR) per RU of each spatial stream, where the average SNR per RU is the arithmetic mean of the SNR (in decibels) for the subcarriers of the 26-tone RU for which feedback is requested.

[0191] The EHT CQI Report field contains EHT CQI reporting information. If the Feedback Type subfield of the EHT MIMO Control field indicates CQI feedback, the EHT CQI Report information is included in the EHT compressed beamforming / CQI report.

[0192] The EHT CQI Report field has the structure and order defined in the HE CQI Report information in the table below. For the EHT CQI Report field, Ncqi is the number of RU indices for which the CQI report is retransmitted to the beamformer. (Mathematical formula: Ncqi = (ruidx(Ncqi - 1) - ruidx(0)) + 1 - Disallowed # of RU26)

[0193] The average SNR of space-time stream i for RU index k is a 6-bit 2s complement integer.

[0194] FieldSize(bits)MeaningAverage SNR for space-time stream 1 for RUindex k = ruidx(0)6SNR at the beamformee for space-time stream 1 averaged over 26-tone RU. See Table 3 (Average SNR of RU index k for space-time stream i subfield)…Average SNR for space-time stream Nc forRU index k = ruidx(0)6SNR at the beamformee for space-time stream Nc averaged over 26-tone RU. See Table 3 (Average SNR of RU index k for space-time stream i subfield)Average SNR for space-time stream 1 for RUindex k = ruidx(1)6SNR at the beamformee for space-time stream 1 averaged over 26-tone RU. See Table 3 (Average SNR of RU index k for space-time stream i subfield)…Average SNR for space-time stream Nc forRU index k = ruidx(1)6SNR at the beamformee for space-time stream Nc averaged over 26-tone RU. See Table 3 (Average SNR of RU index k for space-time stream i subfield)…Average SNR for space-time stream 1 for RUindex k = ruidx(Ncqi - 1)6SNR at the beamformee for space-time stream 1 averaged over 26-tone RU.See Table 3 (Average SNR of RU index k for space-time stream i subfield)… Average SNR for space-time stream Nc forRU index k = ruidx(Ncqi - 1)6SNR at the beamformee for space-time stream Nc averaged over 26-tone RU. See Table 3 (Average SNR of RU index k for space-time stream i subfield).

[0195] Average SNR of RU index k for space-time stream iAvgSNR k,i (dB)-32<=-10-31-9-30-8… … 305231>=53

[0196] 2. How to configure the NDP Announcement frame to indicate the newly configured CQI Report field.

[0197] In existing Wi-Fi systems, Compressed Beamforming / CQI frames were used as one of the methods for feedbacking channel status. When the feedback type was CQI, the CQI Report field was included in the Compressed Beamforming / CQI frame, and the 26-tone CQI for the resource area indicated by the AP was fed back for each stream. In this case, if the CQI for the entire 320MHz band was fed back, 6 bits per STA * 9 RUs per 20MHz * 16 channels (= 864 bits) * Feedback bits equal to the number of streams were required.

[0198] However, when feeding back CQI in 242-tone RU units, only 6 bits * 16 channels (= 96 bits) * number of streams per STA are required, reducing feedback overhead.

[0199] Unless a small RU (less than 242-tone RU) is allocated, the CQI information required to determine the MCS (Modulation and Coding Scheme) may be sufficient only with feedback of the CQI value for larger units such as 242-tone RU or 484-tone RU rather than 26-tone RU units.

[0200] For example, when using a transmission method that applies different MCSs to one or more (M)RUs for one STA, it is desirable to allocate a Large RU (242-tone RU or more) to each (M)RU to which each MCS is applied, and the channel measurement method proposed in this specification can be considered as a channel measurement method to support this transmission method.

[0201] Therefore, in this specification, we will look at a method for more efficient feedback in a wide bandwidth such as 320MHz.

[0202] The CQI (Channel Quality Information) mentioned in this specification is SNR (Signal-to-Noise Ratio) or CSI matrix (H eff ) or channel information such as RSSI (receive signal strength indicator), or the Recommended MCS value. We previously assumed 6 bits for each CQI value, but the number of bits to express may vary depending on the case. (For example, 4 bits for MCS, etc.)

[0203] That is, this embodiment proposes a method to support CQI feedback in larger RU units in a wideband as the bandwidth is expanded to 320 MHz. The CQI Report field for this purpose can be configured as follows.

[0204] 1) Newly proposed CQI Report information

[0205] CQI Report information can be defined as shown in the table below.

[0206] FieldMeaningAverage CQI for space-time 1 for RU indexk=ruidx(0)CQI at the beamformee for space-time stream 1 averaged over A-tone RU……Average CQI for space-timeNcfor RU indexk=ruidx(0)CQI at the beamformee for space-time streamNcaveraged over A-tone RUAverage CQI for space-time 1 for RU indexk=ruidx(1)CQI at the beamformee for space-time stream 1 averaged over A-tone RU……Average CQI for space-timeNcfor RU indexk=ruidx(1)CQI at the beamformee for space-time streamNcaveraged over A-tone RUAverage CQI for space-time 1 for RU indexk=ruidx(Ncqi-1)CQI at the beamformee for space-time stream 1 averaged over A-tone RU……Average CQI for space-timeNcfor RU indexk=ruidx(Ncqi-1)CQI at the beamformee for space-time streamNcaveraged over A-tone RU

[0207] Here, Average CQI for space-time i for RU index k represents the arithmetic mean of CQI per subcarrier in decibels for the subcarriers corresponding to the kth RU index of the ith spatial stream, and can be, for example, a value expressed by quantizing SNR into 6 bits. i can be from 1 to Nc (Nc is the number of spatial streams), and k can be from 1 to the number of A-tone RUs (Ncqi) within the frequency details to be reported, which can be expressed as ruidx(0) to ruidx(Ncqi-1) as shown in the previous table. That is, ruidx(0) represents the first A-tone RU, and ruidx(Ncqi-1) represents the Ncqi-th A-tone RU.

[0208] Examples of A-tone RUs include 242-tone RU, 484-tone RU, or 996-tone RU for Large RU allocation. For example, if A=242, the number of A-tone RUs can be the number of '1's expressed in the 8-bit bitmap when the Resolution bit='0' in the Partial BW subfield (resolution of 20MHz), and can be (the number of '1's expressed) x 2 in the 8-bit bitmap when the Resolution bit='1' (resolution of 40MHz). For example, when BW=320MHz and the Resolution bit='1', if the 8-bit bitmap is 11000000, the number of 484-tone RUs can be 2, and the number of 242-tone RUs can be 4, which is twice the number of 484-tone RUs.

[0209] As another example, if the Resolution bit = '0', A = 242-tone RU can be set, and if the Resolution bit = '1', A = 484-tone RU can be set. In this case, the number of A-tone RUs can be the number expressed as '1' among the 8-bit bitmaps.

[0210] 2) How to configure a new CQI Report field to feedback CQI values ​​for larger units such as 242-tone RU or 484-tone RU.

[0211] Unlike the existing CQI Report field configuration, in order to indicate the newly configured CQI Report field, the AP must indicate the two separately. The following indication method can be suggested in the NDP Announcement frame.

[0212] i) Indicate a new CQI report using one of the reserved bits in the STA Info field of the NDP Announcement frame.

[0213] For example, the AP can use one of the reserved bits of the STA Info field of the NDP Announcement frame to indicate. That is, if Feedback Type='11' and Codebook Size='0', a CQI report is indicated (see Table 1 above). In this case, if the reserved bit is '0' (or '1'), it can indicate that feedback is to be provided using the existing method (CQI feedback in 26-tone RU units), and if the reserved bit is '1' (or '0'), it can indicate that feedback is to be provided using the new method (CQI feedback in A-tone RU units).

[0214] ii) Redefine the meaning of the Feedback Type and Codebook size subfields of the STA Info field of the NDP Announcement frame to indicate a new CQI report.

[0215] For example, an AP can indicate a new method by redefining the meaning of one of the Feedback Type and Codebook size subfields of the STA Info field of the NDP Announcement frame. For example, if Feedback Type = '11' and Codebook Size = '1', it can be redefined to indicate CQI feedback in units of A-tone RUs, rather than the existing MU with Ng = 16 (see Table 1 above).

[0216] iii) Replace the existing CQI report with a new CQI report.

[0217] As another example, a newly configured CQI Report field can replace an existing CQI Report field. In this case, no other instruction is required other than indicating a CQI report when Feedback Type='11' and Codebook Size='0'.

[0218] For the NDP sounding procedure configured in the above manner, the AP can operate as follows.

[0219] - AP can transmit an NDP Announcement frame to inform the STA ID that must perform CQI Feedback in A-tone RU units, the frequency range and stream that must be measured for each STA, and the Feedback Type.

[0220] - After that, the AP can transmit an NDP frame to inform the STAs indicated through the NDP Announcement frame of the sequence / signal for the A-tone RU(s) to be actually measured.

[0221] - Afterwards, the AP can transmit a Trigger frame to inform each STA of the frequency / space / time domains in which the Feedback value should be reported, as well as the reporting method. If there is only one STA that needs to perform Feedback, this process may be omitted.

[0222] - After that, the AP can receive CQI feedback values ​​in units of A-tone RU from STAs and use them as a reference for scheduling the transmission and reception of STAs. For example, the AP can determine the frequency / space / time domain, MCS, coding type, etc. of one or more appropriate A-tone RU units for each STA and transmit or instruct the STA to transmit actual data.

[0223] STA can also operate as follows:

[0224] - STA can receive NDP Announcement frame and NDP frame transmitted by AP.

[0225] - If the received information includes its own ID, the STA can prepare and transmit CQI Feedback in A-tone RU units according to the instructions.

[0226] - After that, actual data can be received from the AP in the frequency / space / time domain in units of A-tone RU (or higher). Alternatively, data from the STA can be transmitted in the frequency / space / time domain in units of A-tone RU (or higher) according to the instructions of the AP.

[0227] Fig. 18 is a flowchart illustrating the operation of a transmitting device according to the present embodiment.

[0228] An example of FIG. 18 may be performed at a transmitting STA or transmitting device (AP and / or non-AP STA).

[0229] Some of the steps (or detailed sub-steps described below) in the example of Fig. 18 may be omitted or changed.

[0230] Through step S1810, the transmitting device (transmitting STA) can obtain information regarding the aforementioned Tone Plan. As described above, the information regarding the Tone Plan includes the size and location of the RU, control information related to the RU, information regarding the frequency band in which the RU is included, information regarding the STA receiving the RU, etc.

[0231] Through step S1820, the transmitting device can configure / generate a PPDU based on the acquired control information. The step of configuring / generating the PPDU may include a step of configuring / generating each field of the PPDU. That is, step S1820 may include a step of configuring an EHT-SIG field including control information regarding a Tone Plan. That is, step S1820 may include a step of configuring a field including control information indicating the size / position of an RU (e.g., an N bitmap) and / or a step of configuring a field including an identifier (e.g., an AID) of an STA receiving the RU.

[0232] Additionally, step S1820 may include a step of generating an STF / LTF sequence to be transmitted through a specific RU. The STF / LTF sequence may be generated based on a preset STF generation sequence / LTF generation sequence.

[0233] Additionally, step S1820 may include a step of generating a data field (i.e., MPDU) to be transmitted via a specific RU.

[0234] The transmitting device can transmit the PPDU configured through step S1820 to the receiving device based on step S1830.

[0235] While performing step S1830, the transmitting device may perform at least one of operations such as CSD, Spatial Mapping, IDFT / IFFT operation, and GI insertion.

[0236] A signal / field / sequence configured according to this specification can be transmitted in the form of FIG. 5.

[0237] Fig. 19 is a flowchart illustrating the operation of a receiving device according to the present embodiment.

[0238] The above-described PPDU can be received according to an example of FIG. 19.

[0239] An example of FIG. 19 may be performed at a receiving STA or receiving device (AP and / or non-AP STA).

[0240] Some of the steps (or detailed sub-steps described below) in the example of Fig. 19 may be omitted.

[0241] A receiving device (receiving STA) may receive all or part of a PPDU through step S1910. The received signal may have the form of FIG. 5.

[0242] The sub-step of step S1910 can be determined based on step S1830 of Fig. 18. That is, step S1910 can perform an operation to restore the results of the CSD, Spatial Mapping, IDFT / IFFT operations, and GI insert operations applied in step S1830.

[0243] At step S1920, the receiving device can decode all or part of the PPDU. Additionally, the receiving device can obtain control information related to the Tone Plan (i.e., RU) from the decoded PPDU.

[0244] More specifically, the receiving device can decode the L-SIG and EHT-SIG of the PPDU based on the Legacy STF / LTF and obtain information included in the L-SIG and EHT SIG fields. Information regarding various Tone Plans (i.e., RUs) described herein can be included in the EHT-SIG, and the receiving STA can obtain information regarding the Tone Plan (i.e., RU) through the EHT-SIG.

[0245] In step S1930, the receiving device can decode the remaining portion of the PPDU based on the information about the Tone Plan (i.e., RU) acquired through step S1920. For example, the receiving STA can decode the STF / LTF field of the PPDU based on the information about one Plan (i.e., RU). In addition, the receiving STA can decode the data field of the PPDU based on the information about the Tone Plan (i.e., RU) and acquire the MPDU included in the data field.

[0246] Additionally, the receiving device may perform a processing operation to transmit the decoded data to a higher layer (e.g., MAC layer) through step S1930. Additionally, if the generation of a signal is instructed from the higher layer to the PHY layer in response to the data transmitted to the higher layer, a subsequent operation may be performed.

[0247] Hereinafter, the above-described embodiment will be described with reference to FIGS. 1 to 19.

[0248] FIG. 20 is a flowchart illustrating a procedure for performing sounding by configuring an NDPA frame to report a CQI in a new unit according to the present embodiment.

[0249] An example of FIG. 20 can be performed in a network environment that supports a next-generation wireless LAN system (UHR (Ultra High Reliability) wireless LAN system or next wi-fi). The next-generation wireless LAN system is a wireless LAN system that improves on the 802.11be system and can satisfy backward compatibility with the 802.11be system.

[0250] An example of FIG. 20 is performed at a transmitting STA, which may correspond to a beamformer or an access point (AP). The receiving STA of FIG. 35 may correspond to a beamformee or at least one STA (station).

[0251] The present embodiment proposes a method for constructing an NDPA frame to support CQI feedback in units of 242-tone RUs or more. In particular, the present embodiment proposes a method for supporting CQI feedback in units of 242-tone RUs or more through reserved bits of the NDPA frame and constructing a new CQI reporting field.

[0252] In step S2010, the transmitting STA (station) transmits an NDPA (Null Data Packet Announcement) frame to the receiving STA.

[0253] In step S2020, the transmitting STA transmits an NDP frame to the receiving STA.

[0254] In step S2030, the transmitting STA receives a feedback frame based on the NDPA frame and the NDP frame from the receiving STA.

[0255] The above NDPA frame includes a Feedback Type And Ng subfield, a Codebook Size subfield, and a Reserved subfield.

[0256] One bit of the above Reserved subfield contains information about the unit of the CQI (Channel Quality Indicator) being fed back. The feedback frame includes the CQI. In this case, the CQI can be fed back for each spatial stream in the RU unit to which the CQI is fed back within the channel bandwidth measured by the NDPA.

[0257] If the above 1 bit is set to 0, the unit of the fed-back CQI may be a 26-tone RU (Resource Unit). If the above 1 bit is set to 1, the unit of the fed-back CQI may be a 242-tone RU, a 484-tone RU, or a 996-tone RU.

[0258] That is, the present embodiment proposes a method to support CQI feedback in new units (units of 242-tone RU or more) through the reserved bits of the NDPA frame. Previously, when the feedback type was CQI, CQI in units of 26-tone RU was fed back for each spatial stream, but the present embodiment has the effect of reducing feedback overhead and increasing channel efficiency by being able to feed back CQI in units of 242-tone RU or more.

[0259] In particular, the use of beamforming in Wi-Fi employing MIMO (Multiple Input Multiple Output) in 802.11bn wireless LAN systems is an important technology. While feedback in small resource units can be helpful for channel measurement to improve performance, there is a problem that it can also cause overhead. Accordingly, there is a need to design a low-complexity feedback technique that improves feedback granularity, and this embodiment has the effect of solving this problem by changing the CQI feedback unit in a wide band.

[0260] When the Feedback Type And Ng subfield is set to 11 and the Codebook Size subfield is set to 0, reporting of the CQI may be indicated.

[0261] The above NDPA frame may further include a Partial BW Info subfield. The Partial BW Info subfield may include a Resolution subfield consisting of 1 bit and a Feedback Bitmap subfield consisting of 8 bits.

[0262] If the size of the channel bandwidth measured by the above NDPA is less than 320 MHz, the Resolution subfield may be set to 0 and the feedback unit of the Feedback Bitmap subfield may include information that it is a 242-tone RU (or 20 MHz).

[0263] If the size of the channel bandwidth measured by the above NDPA is greater than or equal to 320 MHz, the Resolution subfield may be set to 1 and the feedback unit of the Feedback Bitmap subfield may include information that it is 484-tone RU (or 40 MHz).

[0264] For example, if the unit of the CQI being fed back is 242-tone RU and the Resolution subfield is set to 0, the number of 242-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA may be set to the number set to 1 in the Feedback Bitmap subfield.

[0265] For example, if the channel bandwidth measured by the NDPA is 160 MHz and the Feedback Bitmap subfield is 11011011, the number of 242-tone RUs to which the CQI is fed back may be 6. In this case, the CQI may include an average CQI per spatial stream for a first 242-tone RU, an average CQI per spatial stream for a second 242-tone RU, an average CQI per spatial stream for a third 242-tone RU, an average CQI per spatial stream for a fourth 242-tone RU, an average CQI per spatial stream for a fifth 242-tone RU, and an average CQI per spatial stream for a sixth 242-tone RU.

[0266] As another example, if the unit of the CQI being fed back is 242-tone RU and the Resolution subfield is set to 1, the number of 242-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA may be set to twice the number set to 1 in the Feedback Bitmap subfield.

[0267] For example, if the channel bandwidth measured by the NDPA is 320 MHz and the Feedback Bitmap subfield is 11001001, the number of 242-tone RUs to which the CQI is fed back may be 8. At this time, the CQI may include an average CQI per spatial stream for a first 242-tone RU, an average CQI per spatial stream for a second 242-tone RU, an average CQI per spatial stream for a third 242-tone RU, an average CQI per spatial stream for a fourth 242-tone RU, an average CQI per spatial stream for a fifth 242-tone RU, an average CQI per spatial stream for a sixth 242-tone RU, an average CQI per spatial stream for a seventh 242-tone RU, and an average CQI per spatial stream for an eighth 242-tone RU.

[0268] As another example, if the unit of the CQI being fed back is 484-tone RU and the Resolution subfield is set to 1, the number of 484-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA may be set to the number set to 1 in the Feedback Bitmap subfield.

[0269] For example, if the channel bandwidth measured by the NDPA is 320 MHz and the Feedback Bitmap subfield is 11001001, the number of 484-tone RUs to which the CQI is fed back may be 4. In this case, the CQI may include an average CQI per spatial stream for the first 484-tone RU, an average CQI per spatial stream for the second 484-tone RU, an average CQI per spatial stream for the third 484-tone RU, and an average CQI per spatial stream for the fourth 484-tone RU.

[0270] If the receiving STA is one STA, a non-TB (Trigger Based) sounding method is used, such as steps S2010 to S2030. However, if the receiving STA is a plurality of STAs (i.e., in the case of MU feedback), a TB sounding method that triggers the feedback frame using a BFRP (Beamforming Report Poll) trigger frame may be used between steps S2020 and S2030. Specifically, the transmitting STA can transmit the BFRP trigger frame after transmitting the NDP frame, and receive the feedback frame triggered by the BFRP trigger frame. The BFRP trigger frame includes at least one user information field, and only a receiving STA identified by the user information field can transmit the feedback frame.

[0271] The above NDP frame and the above feedback frame may be transmitted in the same band as the NDPA frame. The NDP frame may be defined as a variant of the UHR MU (Multi User) PPDU.

[0272] FIG. 21 is a flowchart illustrating a procedure for performing sounding by receiving an NDPA frame configured to perform a CQI report in a new unit according to the present embodiment.

[0273] An example of FIG. 21 can be performed in a network environment that supports a next-generation wireless LAN system (UHR (Ultra High Reliability) wireless LAN system or next wi-fi). The next-generation wireless LAN system is a wireless LAN system that improves on the 802.11be system and can satisfy backward compatibility with the 802.11be system.

[0274] An example of FIG. 21 is performed at a receiving STA, which may correspond to a beamformee or at least one STA (station). The transmitting STA of FIG. 21 may correspond to a beamformer or an AP (access point).

[0275] The present embodiment proposes a method for constructing an NDPA frame to support CQI feedback in units of 242-tone RUs or more. In particular, the present embodiment proposes a method for supporting CQI feedback in units of 242-tone RUs or more through reserved bits of the NDPA frame and constructing a new CQI reporting field.

[0276] In step S2110, the receiving STA (station) receives an NDPA (Null Data Packet Announcement) frame from the transmitting STA.

[0277] In step S2120, the receiving STA receives an NDP frame from the transmitting STA.

[0278] In step S2130, the receiving STA transmits a feedback frame to the transmitting STA based on the NDPA frame and the NDP frame.

[0279] The above NDPA frame includes a Feedback Type And Ng subfield, a Codebook Size subfield, and a Reserved subfield.

[0280] One bit of the above Reserved subfield contains information about the unit of the CQI (Channel Quality Indicator) being fed back. The feedback frame includes the CQI. In this case, the CQI can be fed back for each spatial stream in the RU unit to which the CQI is fed back within the channel bandwidth measured by the NDPA.

[0281] If the above 1 bit is set to 0, the unit of the fed-back CQI may be a 26-tone RU (Resource Unit). If the above 1 bit is set to 1, the unit of the fed-back CQI may be a 242-tone RU, a 484-tone RU, or a 996-tone RU.

[0282] That is, the present embodiment proposes a method to support CQI feedback in new units (units of 242-tone RU or more) through the reserved bits of the NDPA frame. Previously, when the feedback type was CQI, CQI in units of 26-tone RU was fed back for each spatial stream, but the present embodiment has the effect of reducing feedback overhead and increasing channel efficiency by being able to feed back CQI in units of 242-tone RU or more.

[0283] In particular, the use of beamforming in Wi-Fi employing MIMO (Multiple Input Multiple Output) in 802.11bn wireless LAN systems is an important technology. While feedback in small resource units can be helpful for channel measurement to improve performance, there is a problem that it can also cause overhead. Accordingly, there is a need to design a low-complexity feedback technique that improves feedback granularity, and this embodiment has the effect of solving this problem by changing the CQI feedback unit in a wide band.

[0284] When the Feedback Type And Ng subfield is set to 11 and the Codebook Size subfield is set to 0, reporting of the CQI may be indicated.

[0285] The above NDPA frame may further include a Partial BW Info subfield. The Partial BW Info subfield may include a Resolution subfield consisting of 1 bit and a Feedback Bitmap subfield consisting of 8 bits.

[0286] If the size of the channel bandwidth measured by the above NDPA is less than 320 MHz, the Resolution subfield may be set to 0 and the feedback unit of the Feedback Bitmap subfield may include information that it is a 242-tone RU (or 20 MHz).

[0287] If the size of the channel bandwidth measured by the above NDPA is greater than or equal to 320 MHz, the Resolution subfield may be set to 1 and the feedback unit of the Feedback Bitmap subfield may include information that it is 484-tone RU (or 40 MHz).

[0288] For example, if the unit of the CQI being fed back is 242-tone RU and the Resolution subfield is set to 0, the number of 242-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA may be set to the number set to 1 in the Feedback Bitmap subfield.

[0289] For example, if the channel bandwidth measured by the NDPA is 160 MHz and the Feedback Bitmap subfield is 11011011, the number of 242-tone RUs to which the CQI is fed back may be 6. In this case, the CQI may include an average CQI per spatial stream for a first 242-tone RU, an average CQI per spatial stream for a second 242-tone RU, an average CQI per spatial stream for a third 242-tone RU, an average CQI per spatial stream for a fourth 242-tone RU, an average CQI per spatial stream for a fifth 242-tone RU, and an average CQI per spatial stream for a sixth 242-tone RU.

[0290] As another example, if the unit of the CQI being fed back is 242-tone RU and the Resolution subfield is set to 1, the number of 242-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA may be set to twice the number set to 1 in the Feedback Bitmap subfield.

[0291] For example, if the channel bandwidth measured by the NDPA is 320 MHz and the Feedback Bitmap subfield is 11001001, the number of 242-tone RUs to which the CQI is fed back may be 8. At this time, the CQI may include an average CQI per spatial stream for a first 242-tone RU, an average CQI per spatial stream for a second 242-tone RU, an average CQI per spatial stream for a third 242-tone RU, an average CQI per spatial stream for a fourth 242-tone RU, an average CQI per spatial stream for a fifth 242-tone RU, an average CQI per spatial stream for a sixth 242-tone RU, an average CQI per spatial stream for a seventh 242-tone RU, and an average CQI per spatial stream for an eighth 242-tone RU.

[0292] As another example, if the unit of the CQI being fed back is 484-tone RU and the Resolution subfield is set to 1, the number of 484-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA may be set to the number set to 1 in the Feedback Bitmap subfield.

[0293] For example, if the channel bandwidth measured by the NDPA is 320 MHz and the Feedback Bitmap subfield is 11001001, the number of 484-tone RUs to which the CQI is fed back may be 4. In this case, the CQI may include an average CQI per spatial stream for the first 484-tone RU, an average CQI per spatial stream for the second 484-tone RU, an average CQI per spatial stream for the third 484-tone RU, and an average CQI per spatial stream for the fourth 484-tone RU.

[0294] If the receiving STA is one STA, a non-TB (Trigger Based) sounding method is used, such as steps S2010 to S2030. However, if the receiving STA is a plurality of STAs (i.e., in the case of MU feedback), a TB sounding method that triggers the feedback frame using a BFRP (Beamforming Report Poll) trigger frame may be used between steps S2020 and S2030. Specifically, the transmitting STA can transmit the BFRP trigger frame after transmitting the NDP frame, and receive the feedback frame triggered by the BFRP trigger frame. The BFRP trigger frame includes at least one user information field, and only a receiving STA identified by the user information field can transmit the feedback frame.

[0295] The above NDP frame and the above feedback frame may be transmitted in the same band as the NDPA frame. The NDP frame may be defined as a variant of the UHR MU (Multi User) PPDU.

[0296] <Device Configuration>

[0297] The technical features of the present specification described above can be applied to various devices and methods. For example, the technical features of the present specification described above can be performed / supported by the devices of FIG. 1 and / or FIG. 14. For example, the technical features of the present specification described above can be applied only to a part of FIG. 1 and / or FIG. 14. For example, the technical features of the present specification described above can be implemented based on the processing chip (114, 124) of FIG. 1, or based on the processor (111, 121) and the memory (112, 122) of FIG. 1, or based on the processor (610) and the memory (620) of FIG. 14. For example, the device of the present specification receives an NDPA (Null Data Packet Announcement) frame from a transmitting STA (station); receives an NDP frame from the transmitting STA; and transmits a feedback frame to the transmitting STA based on the NDPA frame and the NDP frame.

[0298] The technical features of this specification can be implemented based on a computer-readable medium (CRM). For example, the CRM proposed by this specification is at least one computer-readable recording medium containing instructions that are executed by at least one processor.

[0299] The CRM may store instructions for performing operations including: receiving an NDPA (Null Data Packet Announcement) frame from a transmitting STA; receiving an NDP frame from the transmitting STA; and transmitting a feedback frame based on the NDPA frame and the NDP frame to the transmitting STA. The instructions stored in the CRM of the present specification may be executed by at least one processor. At least one processor related to the CRM of the present specification may be the processor (111, 121) or the processing chip (114, 124) of FIG. 1, or the processor (610) of FIG. 14. Meanwhile, the CRM of the present specification may be the memory (112, 122) of FIG. 1, the memory (620) of FIG. 14, or a separate external memory / storage medium / disk, etc.

[0300] The technical features of this specification described above are applicable to various applications and business models. For example, the technical features described above can be applied to wireless communication in devices that support artificial intelligence (AI).

[0301] Artificial intelligence (AI) is the study of artificial intelligence or the methodologies for creating it, while machine learning (ML) defines various problems in the field of AI and studies the methodologies for solving them. Machine learning is also defined as an algorithm that improves performance on a task through consistent experience.

[0302] An artificial neural network (ANN) is a model used in machine learning. It can refer to a model with problem-solving capabilities, consisting of artificial neurons (nodes) formed by the connection of synapses to form a network. An ANN can be defined by the connection patterns between neurons in different layers, the learning process that updates model parameters, and the activation function that generates output values.

[0303] An artificial neural network may include an input layer, an output layer, and optionally one or more hidden layers. Each layer contains one or more neurons, and the artificial neural network may include synapses connecting neurons. In an artificial neural network, each neuron can output a function value of an activation function based on input signals, weights, and biases received through the synapses.

[0304] Model parameters are parameters determined through learning, including synaptic connection weights and neuron biases. Hyperparameters are parameters that must be set before learning in machine learning algorithms, including the learning rate, number of iterations, mini-batch size, and initialization function.

[0305] The goal of artificial neural network training can be seen as determining model parameters that minimize a loss function. The loss function can be used as an indicator for determining optimal model parameters during the artificial neural network training process.

[0306] Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning depending on the learning method.

[0307] Supervised learning refers to a method for training an artificial neural network when given labels for the training data. The labels can refer to the correct answer (or output value) that the artificial neural network must infer when the training data is input to the artificial neural network. Unsupervised learning can refer to a method for training an artificial neural network when the training data is not given labels. Reinforcement learning can refer to a learning method in which an agent defined within a given environment is trained to select actions or action sequences that maximize the cumulative reward in each state.

[0308] Machine learning implemented with a deep neural network (DNN) containing multiple hidden layers among artificial neural networks is also called deep learning, and deep learning is a subset of machine learning. Hereinafter, the term "machine learning" is used to encompass deep learning.

[0309] Additionally, the above-described technical features can be applied to wireless communication of robots.

[0310] A robot can be defined as a machine that automatically performs or operates a given task based on its own capabilities. Specifically, a robot capable of perceiving its environment, making independent judgments, and performing actions can be called an intelligent robot.

[0311] Robots can be categorized into industrial, medical, household, and military applications based on their intended use or field. Robots are equipped with actuators or motors, enabling them to perform various physical actions, such as moving robot joints. Furthermore, mobile robots incorporate wheels, brakes, and propellers into their actuators, enabling them to move on the ground or fly in the air.

[0312] Additionally, the above-described technical features can be applied to devices that support extended reality.

[0313] Extended reality is a general term for virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology presents real-world objects and backgrounds as CG images only, AR technology presents virtual CG images over images of real objects, and MR technology is a computer graphics technology that blends and combines virtual objects with the real world.

[0314] MR technology is similar to AR in that it presents both real and virtual objects simultaneously. However, while AR uses virtual objects to complement real objects, MR uses virtual and real objects on an equal footing.

[0315] XR technology can be applied to HMD (Head-Mount Display), HUD (Head-Up Display), mobile phones, tablet PCs, laptops, desktops, TVs, digital signage, etc., and devices to which XR technology is applied can be called XR devices.

[0316] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined and implemented as a device, and the technical features of the device claims of this specification may be combined and implemented as a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a method.

Claims

1. In a wireless LAN system, A step in which a receiving STA (station) receives an NDPA (Null Data Packet Announcement) frame from a transmitting STA; The step of the receiving STA receiving an NDP frame from the transmitting STA; and The receiving STA comprises a step of transmitting a feedback frame based on the NDPA frame and the NDP frame to the transmitting STA, The above NDPA frame includes a Feedback Type And Ng subfield, a Codebook Size subfield, and a Reserved subfield, One bit of the above Reserved subfield contains information about the unit of the CQI (Channel Quality Indicator) being fed back, and The above feedback frame includes the CQI. method.

2. In paragraph 1, If the Feedback Type And Ng subfield is set to 11 and the Codebook Size subfield is set to 0, reporting of the CQI is indicated. The above CQI is fed back per spatial stream in RU units within the channel bandwidth measured by the NDPA. method.

3. In paragraph 1, If the above 1 bit is set to 0, the unit of the fed-back CQI is a 26-tone RU (Resource Unit), If the above 1 bit is set to 1, the unit of the fed-back CQI is 242-tone RU, 484-tone RU, or 996-tone RU. method.

4. In paragraph 1, The above NDPA frame further includes a Partial BW Info subfield, The above Partial BW Info subfield includes a Resolution subfield consisting of 1 bit and a Feedback Bitmap subfield consisting of 8 bits, If the size of the channel bandwidth measured by the NDPA is less than 320 MHz, the Resolution subfield is set to 0 and the Feedback Bitmap subfield includes information that the feedback unit is 242-tone RU. If the size of the channel bandwidth measured by the above NDPA is greater than or equal to 320 MHz, the Resolution subfield is set to 1 and the feedback unit of the Feedback Bitmap subfield includes information that it is a 484-tone RU. method.

5. In paragraph 4, If the unit of the CQI fed back is 242-tone RU and the Resolution subfield is set to 0, the number of 242-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA is set to the number set to 1 in the Feedback Bitmap subfield. method.

6. In paragraph 5, If the channel bandwidth measured by the above NDPA is 160MHz and the Feedback Bitmap subfield is 11011011, the number of 242-tone RUs to which the CQI is fed back is 6, The above CQI includes a spatial stream-wise average CQI for the first 242-tone RU, a spatial stream-wise average CQI for the second 242-tone RU, a spatial stream-wise average CQI for the third 242-tone RU, a spatial stream-wise average CQI for the fourth 242-tone RU, a spatial stream-wise average CQI for the fifth 242-tone RU, and a spatial stream-wise average CQI for the sixth 242-tone RU. method.

7. In paragraph 4, If the unit of the CQI fed back is 242-tone RU and the Resolution subfield is set to 1, the number of 242-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA is set to twice the number set to 1 in the Feedback Bitmap subfield. method.

8. In paragraph 7, If the channel bandwidth measured by the above NDPA is 320 MHz and the Feedback Bitmap subfield is 11001001, the number of 242-tone RUs to which the CQI is fed back is 8, The above CQI includes a spatial stream-wise average CQI for the first 242-tone RU, a spatial stream-wise average CQI for the second 242-tone RU, a spatial stream-wise average CQI for the third 242-tone RU, a spatial stream-wise average CQI for the fourth 242-tone RU, a spatial stream-wise average CQI for the fifth 242-tone RU, a spatial stream-wise average CQI for the sixth 242-tone RU, a spatial stream-wise average CQI for the seventh 242-tone RU, and a spatial stream-wise average CQI for the eighth 242-tone RU. method.

9. In paragraph 4, If the unit of the CQI fed back is 484-tone RU and the Resolution subfield is set to 1, the number of 484-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA is set to the number set to 1 in the Feedback Bitmap subfield. method.

10. In paragraph 9, If the channel bandwidth measured by the above NDPA is 320 MHz and the Feedback Bitmap subfield is 11001001, the number of 484-tone RUs to which the CQI is fed back is 4, The above CQI includes the average CQI per spatial stream for the first 484-tone RU, the average CQI per spatial stream for the second 484-tone RU, the average CQI per spatial stream for the third 484-tone RU, and the average CQI per spatial stream for the fourth 484-tone RU. method.

11. In a wireless LAN system, a receiving STA (station) memory; transceiver; and A processor operatively coupled to the memory and the transceiver, the processor comprising: Receive an NDPA (Null Data Packet Announcement) frame from a transmitting STA; Receive an NDP frame from the transmitting STA; and Transmitting a feedback frame based on the NDPA frame and the NDP frame to the transmitting STA, The above NDPA frame includes a Feedback Type And Ng subfield, a Codebook Size subfield, and a Reserved subfield, One bit of the above Reserved subfield contains information about the unit of the CQI (Channel Quality Indicator) being fed back, and The above feedback frame includes the CQI. Receiving STA.

12. In a wireless LAN system, A step in which a transmitting STA (station) transmits an NDPA (Null Data Packet Announcement) frame to a receiving STA; The step of the transmitting STA transmitting an NDP frame to the receiving STA; and The transmitting STA comprises a step of receiving a feedback frame based on the NDPA frame and the NDP frame from the receiving STA, The above NDPA frame includes a Feedback Type And Ng subfield, a Codebook Size subfield, and a Reserved subfield, One bit of the above Reserved subfield contains information about the unit of the CQI (Channel Quality Indicator) being fed back, and The above feedback frame includes the CQI. method.

13. In paragraph 12, If the Feedback Type And Ng subfield is set to 11 and the Codebook Size subfield is set to 0, reporting of the CQI is indicated. The above CQI is fed back per spatial stream in RU units within the channel bandwidth measured by the NDPA. method.

14. In paragraph 12, If the above 1 bit is set to 0, the unit of the fed-back CQI is a 26-tone RU (Resource Unit), If the above 1 bit is set to 1, the unit of the fed-back CQI is 242-tone RU, 484-tone RU, or 996-tone RU. method.

15. In paragraph 12, The above NDPA frame further includes a Partial BW Info subfield, The above Partial BW Info subfield includes a Resolution subfield consisting of 1 bit and a Feedback Bitmap subfield consisting of 8 bits, If the size of the channel bandwidth measured by the NDPA is less than 320 MHz, the Resolution subfield is set to 0 and the Feedback Bitmap subfield includes information that the feedback unit is 242-tone RU. If the size of the channel bandwidth measured by the above NDPA is greater than or equal to 320 MHz, the Resolution subfield is set to 1 and the feedback unit of the Feedback Bitmap subfield includes information that it is a 484-tone RU. method.

16. In paragraph 15, If the unit of the CQI fed back is 242-tone RU and the Resolution subfield is set to 0, the number of 242-tone RUs in which the CQI is fed back within the channel bandwidth measured by the NDPA is set to the number set to 1 in the Feedback Bitmap subfield. method.

17. In paragraph 16, If the channel bandwidth measured by the above NDPA is 160MHz and the Feedback Bitmap subfield is 11011011, the number of 242-tone RUs to which the CQI is fed back is 6, The above CQI includes a spatial stream-wise average CQI for the first 242-tone RU, a spatial stream-wise average CQI for the second 242-tone RU, a spatial stream-wise average CQI for the third 242-tone RU, a spatial stream-wise average CQI for the fourth 242-tone RU, a spatial stream-wise average CQI for the fifth 242-tone RU, and a spatial stream-wise average CQI for the sixth 242-tone RU. method.

18. In a wireless LAN system, a transmitting STA (station) memory; transceiver; and A processor operatively coupled to the memory and the transceiver, the processor comprising: Transmit an NDPA (Null Data Packet Announcement) frame to the receiving STA; Transmitting an NDP frame to the receiving STA; and Receive a feedback frame based on the NDPA frame and the NDP frame from the receiving STA, The above NDPA frame includes a Feedback Type And Ng subfield, a Codebook Size subfield, and a Reserved subfield, One bit of the above Reserved subfield contains information about the unit of the CQI (Channel Quality Indicator) being fed back, and The above feedback frame includes the CQI. Transmitting STA.

19. At least one computer-readable medium containing instructions based on being executed by at least one processor, A step of receiving an NDPA (Null Data Packet Announcement) frame from a transmitting STA (station); A step of receiving an NDP frame from the transmitting STA; and Including a step of transmitting a feedback frame based on the NDPA frame and the NDP frame to the transmitting STA, The above NDPA frame includes a Feedback Type And Ng subfield, a Codebook Size subfield, and a Reserved subfield, One bit of the above Reserved subfield contains information about the unit of the CQI (Channel Quality Indicator) being fed back, and The above feedback frame includes the CQI. Recording medium.

20. In a wireless LAN system, in a device, memory; and A processor operatively coupled to the memory, the processor comprising: Receive an NDPA (Null Data Packet Announcement) frame from a transmitting STA (station); Receive an NDP frame from the transmitting STA; and Transmitting a feedback frame based on the NDPA frame and the NDP frame to the transmitting STA, The above NDPA frame includes a Feedback Type And Ng subfield, a Codebook Size subfield, and a Reserved subfield, One bit of the above Reserved subfield contains information about the unit of the CQI (Channel Quality Indicator) being fed back, and The above feedback frame includes the CQI. device.

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