Method and apparatus for performing beamforming training procedure group to millimeter wave

Abstract

A method and apparatus for performing a beamforming training process in consideration of a millimeter wave band in a WLAN system is disclosed. A method performed by a first STA in a WLAN system according to the present invention may comprise the steps of: checking, in a first operating frequency band, information related to initiation of a sector scanning operation in a second operating frequency band; measuring an optimal transmission sector of the second STA and performing a reception sector scan of the first STA based on receiving a plurality of frames for a sector scan operation from the second STA in a second operation band; transmitting a feedback frame including identification information on the optimal transmission sector to the second STA in the first operation band; and receiving a response frame to the feedback frame from the second STA in the first operating frequency band.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for performing a beamforming training process considering a millimeter wave (mmWave) frequency band in a wireless local area network (WLAN) system. Background Art

[0002] New technologies have been introduced for wireless local area network (WLAN) to increase transmission rate, increase bandwidth, improve reliability, reduce errors, and reduce latency. Among WLAN technologies, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards can be referred to as Wi-Fi. For example, recently introduced technologies to WLAN include very high throughput (VHT) enhancements of the 802.11ac standard and high efficiency (HE) enhancements of the IEEE 802.11ax standard.

[0003] To provide a more advanced wireless communication environment, improved technologies for extremely high throughput (EHT) are being discussed. For example, technologies for multiple-input multiple-output (MIMO) and multi-access point (AP) coordination that support increased bandwidth, efficient use of multiple bands, and increased spatial streams are being studied, and specifically, various technologies are being studied to support low latency or real-time services. In addition, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technologies. Summary of the Invention

[0004] Technical Problem

[0005] A technical object of the present disclosure is to provide a method and apparatus for performing a beamforming training process considering a millimeter wave (mmWave) frequency band in a wireless local area network (WLAN) system.

[0006] A technical object of the present disclosure is to provide a method and apparatus for performing a sector-level scan (SLS) process and a beam refinement protocol (BRP) process when supporting a millimeter wave frequency band in a WLAN system.

[0007] The technical objects to be achieved by the present disclosure are not limited to the above technical objects, and other technical objects not described herein will be clearly understood by those skilled in the art from the following description.

[0008] Technical Solution

[0009] According to an aspect of the present disclosure, a method performed by a first station (STA) in a wireless LAN system may include: identifying, in a first operating band, information related to initiating a sector scan operation in a second operating band, the information including allocation information of resources for the sector scan operation; in the second operating band, based on receiving, from a second STA in the resources, a plurality of frames for the sector scan operation, measuring a best transmission (TX) sector of the second STA and performing a receive (RX) sector scan of the first STA; in the first operating band, sending a feedback frame including identification information for the best TX sector to the second STA; and in the first operating band, receiving a response frame to the feedback frame from the second STA.

[0010] According to an additional aspect of the present disclosure, a method performed by a second station (STA) in a wireless LAN system may include: identifying, in a first operating band, information related to initiating a sector scan operation in a second operating band, the information including allocation information of resources for the sector scan operation; in the second operating band, sending, in the resources, a plurality of frames for the sector scan operation to the first STA; in the first operating band, receiving, from the first STA, a feedback frame including identification information for a best Tx sector of the second STA; and in the first operating band, sending a response frame to the feedback frame to the first STA.

[0011] Technical effects

[0012] According to the present disclosure, a method and apparatus for performing a beamforming training process considering a millimeter wave (mmWave) frequency band in a wireless local area network (WLAN) system may be provided.

[0013] According to the present disclosure, when a millimeter wave frequency band is supported in a wireless LAN system, a method and apparatus for performing a sector-level scan (SLS) process and a beam refinement protocol (BRP) process may be provided.

[0014] According to the present disclosure, there is an advantage that high data rates and low latency can be achieved by supporting a millimeter wave frequency band in a wireless LAN system.

[0015] The effects that can be achieved by the present disclosure are not limited to the above effects, and those skilled in the relevant art can clearly understand other effects not described herein through the following description. Brief Description of the Drawings

[0016] The drawings included as part of understanding the specific embodiments of the present disclosure provide embodiments of the present disclosure and describe the technical features of the present disclosure together with the specific embodiments.

[0017] Figure 1 A configuration block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0018] Figure 2 It is a diagram illustrating an exemplary structure of a WLAN system to which the present disclosure can be applied.

[0019] Figure 3 It is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0020] Figure 4 It is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0021] Figure 5 It is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0022] Figure 6 It is a diagram illustrating an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0023] Figure 7 It is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0024] Figure 8 It is a diagram for explaining an example of a resource unit of a wireless LAN system to which the present disclosure can be applied.

[0025] Figure 9 It is a diagram for explaining an example of a resource unit of a wireless LAN system to which the present disclosure can be applied.

[0026] Figure 10 It is a diagram for explaining an example of a resource unit of a wireless LAN system to which the present disclosure can be applied.

[0027] Figure 11 It is a diagram showing an example of a channelized area in a millimeter wave (mmWave) band to which the present disclosure can be applied.

[0028] Figure 12 It shows an example of an SLS process between an AP and a STA according to an embodiment of the present disclosure.

[0029] Figure 13 It shows another example of an SLS process between an AP and a STA according to an embodiment of the present disclosure.

[0030] Figure 14 It shows another example of an SLS process between an AP and a STA according to an embodiment of the present disclosure.

[0031] Figure 15 It shows an example of a BRP process between an AP and a STA according to an embodiment of the present disclosure.

[0032] Figure 16 Shows another example of the BRP process between an AP and a STA according to an embodiment of the present disclosure.

[0033] Figure 17 Shows another example of the BRP process between an AP and a STA according to an embodiment of the present disclosure.

[0034] Figure 18 Illustrates an operation flowchart of a first STA according to an embodiment of the present disclosure.

[0035] Figure 19 Illustrates an operation flowchart of a second STA according to an embodiment of the present disclosure. Detailed implementation manners

[0036] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed through the drawings is to describe exemplary embodiments of the present disclosure, rather than indicating the only embodiments in which the present disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art know that the present disclosure can be implemented without these specific details.

[0037] In some cases, known structures and devices may be omitted, or may be shown in the form of block diagrams based on the core functions of each structure and device in order to prevent the concepts of the present disclosure from being ambiguous.

[0038] In the present disclosure, when an element is referred to as being "connected", "combined" or "linked" to another element, it may include an indirect connection relationship as well as a direct connection relationship in which another element exists therebetween. In addition, in the present disclosure, the terms "include" or "have" specify the existence of the mentioned features, steps, operations, components and / or elements, but do not exclude the existence or addition of one or more other features, stages, operations, components, elements and / or their groups.

[0039] In the present disclosure, terms such as "first", "second", etc. are only used to distinguish one element from another element and do not limit the element. Unless otherwise stated, they do not limit the order or importance, etc. between the elements. Therefore, within the scope of the present disclosure, the first element in an embodiment may be referred to as the second element in another embodiment, and similarly, the second element in an embodiment may be referred to as the first element in another embodiment.

[0040] The terms used in this disclosure are for the purpose of describing particular embodiments and are not intended to limit the claims. As used in the description of the embodiments and the appended claims, the singular forms are intended to include the plural forms unless the context clearly indicates otherwise. The term “and / or” as used in this disclosure may refer to one of the related listed items or may mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise stated, the “ / ” between words in this disclosure has the same meaning as “and / or”.

[0041] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to a wireless LAN system. For example, examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to a wireless LAN based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11be version 2 standard corresponding to additional enhancement technologies of the IEEE 802.11be version 1 standard. Additionally, examples of the present disclosure can be applied to a next-generation standard-based wireless LAN after IEEE 802.11be. Furthermore, examples of the present disclosure can be applied to a cellular wireless communication system. For example, it can be applied to a cellular wireless communication system based on the Long-Term Evolution (LTE) technology and the 5G New Radio (NR) technology based on the Third Generation Partnership Project (3GPP) standards.

[0042] Hereinafter, the technical features to which the examples of the present disclosure can be applied will be described.

[0043] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0044] Figure 1 The first device 100 and the second device 200 illustrated in can be replaced with various terms such as a terminal, a wireless device, a wireless transmit-receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSU), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user. Additionally, the first device 100 and the second device 200 include an access point (AP), a base station (BS), a fixed station, a Node B, a base transceiver system (BTS), a network. It can be replaced with various terms such as an artificial intelligence (AI) system, a roadside unit (RSU), a repeater, a router, a relay, and a gateway.

[0045] Figure 1The apparatuses 100 and 200 illustrated in [description] can be referred to as a station (STA). For example, Figure 1 The apparatuses 100 and 200 illustrated in [description] can be referred to by various terms such as a transmitting apparatus, a receiving apparatus, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 can perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 can perform AP and / or non-AP functions. When the STAs 110 and 200 perform the AP function, they can be simply referred to as an AP, and when the STAs 110 and 200 perform the non-AP function, they can be simply referred to as an STA. Additionally, in the present disclosure, an AP can also be indicated as an AP STA.

[0046] Referring to Figure 1 , the first apparatus 100 and the second apparatus 200 can transmit and receive radio signals through various wireless LAN technologies (e.g., the IEEE 802.11 series). The first apparatus 100 and the second apparatus 200 can include interfaces for a media access control (MAC) layer and a physical layer (PHY) compliant with the IEEE 802.11 standard.

[0047] Additionally, in addition to wireless LAN technologies, the first apparatus 100 and the second apparatus 200 can additionally support various communication standard (e.g., 3GPP LTE series, 5G NR series standards, etc.) technologies. Additionally, the apparatuses of the present disclosure can be implemented in various apparatuses such as a mobile phone, a vehicle, a personal computer, an augmented reality (AR) device, and a virtual reality (VR) device. Additionally, the STA of the present specification can support various communication services such as a voice call, a video call, data communication, autonomous driving, machine type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), and IoT (Internet of Things).

[0048] The first device 100 may include one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, the processor 102 may transmit a wireless signal including the first information / signal through the transceiver 106 after generating the first information / signal by processing the information in the memory 104. Additionally, the processor 102 may receive a wireless signal including the second information / signal through the transceiver 106, and then store the information obtained by signal processing of the second information / signal in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for performing all or part of the processing controlled by the processor 102 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and may transmit and / or receive wireless signals through one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used with an RF (radio frequency) unit. In the present disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0049] The second device 200 may include one or more processors 202 and one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, the processor 202 may generate third information / signals by processing the information in the memory 204, and then transmit wireless signals including the third information / signals through the transceiver 206. Additionally, the processor 202 may receive wireless signals including fourth information / signals through the transceiver 206, and then store the information obtained by signal processing of the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software codes including instructions for performing all or part of the processing controlled by the processor 202 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 206 may be connected to the processor 202 and may transmit and / or receive wireless signals through one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used with an RF unit. In the present disclosure, a device may mean a communication modem / circuit / chip.

[0050] Hereinafter, the hardware components of apparatuses 100 and 200 will be described in more detail. Without being limited thereto, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY and MAC). One or more processors 102 and 202 may generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (e.g., baseband signals) from one or more transceivers 106 and 206 according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure, and obtain PDUs, SDUs, messages, control information, data, or information.

[0051] One or more processors 102 and 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processor Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be included in one or more processors 102 and 202, or may be stored in one or more memories 104 and 204 and driven by one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by using firmware or software in the form of codes, instructions, and / or instruction sets.

[0052] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, code, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard disk drives, registers, cache memories, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located inside and / or outside one or more processors 102, 202. Additionally, one or more memories 104, 204 may be connected to one or more processors 102, 202 through various techniques such as wired or wireless connections.

[0053] One or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operation flowcharts, etc. of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts, etc. included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts, etc. included in the present disclosure via one or more antennas 108, 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert the received wireless signals / channels, etc. from RF band signals into baseband signals to process the received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 may convert the user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals into RF band signals. Thus, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0054] For example, one of STAs 100 and 200 may perform the expected operations of an AP, and the other of STAs 100 and 200 may perform the expected operations of a non-AP STA. For example, Figure 1 the transceivers 106 and 206 may perform the operations of transmitting and receiving signals (e.g., packets or physical layer protocol data units (PPDUs) compliant with IEEE 802.11a / b / g / n / ac / ax / be / bn). Additionally, in the present disclosure, the operations of various STAs generating transmit / receive signals or preprocessing or calculating data for transmit / receive signals may be performed by Figure 1are executed by processors 102 and 202. For example, examples of operations for generating transmission / reception signals or performing data processing or calculations in advance for transmission / reception signals may include: 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signals (SIG), short training fields (STF), long training fields (LTF), data, etc.) included in a PPDU; 2) determining / configuring / acquiring time resources or frequency resources (e.g., subcarrier resources) for fields (SIG, STF, LTF, data, etc.) included in a PPDU; 3) determining / configuring / acquiring a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an additional sequence applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in a PPDU operation; 4) power control operations and / or power saving operations applied to an STA; 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding, etc. of an ACK signal. Additionally, in the following examples, various information (e.g., information related to fields / sub-fields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals may be stored in Figure 1 memories 104 and 204.

[0055] Hereinafter, a downlink (DL) may refer to a link for communication from an AP STA to a non-AP STA, and DL PPDUs / packets / signals may be transmitted and received through the DL. In DL communication, the transmitter may be a part of the AP STA, and the receiver may be a part of the non-AP STA. An uplink (UL) may refer to a link for communication from a non-AP STA to an AP STA, and UL PPDUs / packets / signals may be transmitted and received through the UL. In UL communication, the transmitter may be a part of the non-AP STA, and the receiver may be a part of the AP STA.

[0056] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure may be applied.

[0057] The structure of a wireless LAN system may be composed of multiple components. A wireless LAN that supports STA mobility transparent to the upper layer may be provided through the interaction of multiple components. A basic service set (BSS) corresponds to a basic building block of a wireless LAN. Figure 2 Exemplarily, it is shown that there are two BSSs (BSS1 and BSS2), and two STAs included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2The ellipse representing the BSS can also be understood as representing the coverage area where the STAs included in the corresponding BSS maintain communication. This area can be referred to as the Basic Service Area (BSA). When an STA moves outside the BSA, it cannot communicate directly with other STAs within the BSA.

[0058] If the DS shown in Figure 2 is not considered, the most basic BSS type in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimal form that only includes two STAs. For example, assuming other components are omitted, BSS1 that only includes STA1 and STA2 or BSS2 that only includes STA3 and STA4 can respectively correspond to representative examples of an IBSS. This configuration is possible when STAs can communicate directly without an AP. Additionally, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs can consist of mobile STAs and are not allowed to access the Distributed System (DS), thus forming a self-contained network.

[0059] The membership of STAs in a BSS can be dynamically changed by turning on or off STAs, entering or exiting the BSS area, etc. To become a member of a BSS, an STA can use synchronization processing to join the BSS. To access all services of the BSS infrastructure, an STA should be associated with the BSS. This association can be dynamically established and can include using the Distribution System Service (DSS).

[0060] The direct STA-to-STA distance in a wireless LAN may be limited by the PHY performance. In some cases, this distance limitation may be sufficient, but in some cases, communication between STAs at longer distances may be required. The Distributed System (DS) can be configured to support extended coverage.

[0061] DS means the structure for interconnecting BSSs. Specifically, as Figure 2As shown, the BSS can exist as an extended form of a network composed of multiple BSSs. The DS is a logical concept and can be specified by the characteristics of the distributed system medium (DSM). In this regard, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for different purposes and is used by different components. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of the wireless LAN structure (DS structure or other network structures) can be interpreted as multiple media being logically different. That is to say, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be independently specified by the physical characteristics of each implementation.

[0062] The DS can support mobile devices by providing seamless integration of multiple BSSs and providing the logical services necessary for addressing the addresses to the destination. In addition, the DS can also include a component called a portal, which is used as a bridge for the connection between the wireless LAN and other networks (e.g., IEEE 802.X).

[0063] The AP enables access to the DS via the WM for the associated non-AP STA and refers to an entity that also has the STA function. The data movement between the BSS and the DS can be performed by the AP. For example, Figure 2 STA2 and STA3 shown in have the function of the STA and provide the function of allowing the associated non-AP STAs (STA1 and STA4) to access the DS. In addition, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM is not necessarily the same as the address used by the AP for communication on the DSM. The BSS composed of an AP and one or more STAs can be called an infrastructure BSS.

[0064] Data sent from one of the STAs associated with the AP to the STA address of the corresponding AP can always be received at the uncontrolled port and can be processed by the IEEE 802.1X port access entity. In addition, when the controlled port is authenticated, the transmitted data (or frame) can be delivered to the DS.

[0065] In addition to the above DS structure, the extended service set (ESS) can also be configured to provide wide coverage.

[0066] An ESS refers to a network consisting of a DS and BSSs, which can be of any size and complexity. An ESS can correspond to a set of BSSs connected to a DS. However, an ESS does not include the DS. The ESS network is characterized by an IBSS in the logical link control (LLC) layer. STAs included in an ESS can communicate with each other, and a mobile STA can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in an ESS can have the same service set identifier (SSID). The SSID is distinguished from the BSSID, which is the identifier of a BSS.

[0067] The wireless LAN system does not assume anything about the relative physical positions of BSSs, and all of the following forms are possible. BSSs can partially overlap, which is a form commonly used to provide continuous coverage. Additionally, BSSs can be not physically connected, and logically, there is no limit to the distance between BSSs. Additionally, BSSs can be physically located at the same position, which can be used to provide redundancy. Additionally, one (or more than one) IBSS or ESS network can physically exist in the same space as one (or more than one) ESS network. This can correspond to forms of ESS networks when an ad-hoc network operates in a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required at the same location.

[0068] Figure 3 is a diagram for explaining the link establishment process to which the present disclosure can be applied.

[0069] In order for an STA to establish a link with a network and send / receive data, it first discovers the network, performs authentication, establishes an association, and an authentication process is required for security. The link establishment process can also be referred to as a session initiation process or a session establishment process. Additionally, the processes of discovery, authentication, association, and security establishment in the link establishment process can be collectively referred to as an association process.

[0070] In step S310, the STA can perform a network discovery operation. The network discovery operation can include a scanning operation of the STA. That is, in order for the STA to access a network, it needs to find a network it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying the networks existing in a specific area is called scanning.

[0071] Scanning schemes include active scanning and passive scanning. Figure 3A network discovery operation including an active scanning process is exemplarily illustrated. In active scanning, the STA performing the scanning sends a probe request frame to discover which APs exist around it while moving across channels and waits for a response thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that has sent the probe request frame. Here, the responder can be the STA that last sent a beacon frame in the BSS of the channel being scanned. In a BSS, since the AP sends a beacon frame, the AP becomes the responder, and in an IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, the STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information included in the received probe response frame, and can move to the next channel (e.g., channel 2), and perform scanning in the same way (i.e., sending and receiving probe requests / responses on channel 2).

[0072] Although not shown in Figure 3 it, the scanning operation can be performed in a passive scanning manner. In passive scanning, the STA performing the scanning waits for beacon frames while moving across channels. A beacon frame is one of the management frames defined in IEEE 802.11 and is periodically sent to notify the existence of a wireless network and to allow the STA performing the scanning to find the wireless network and participate in the wireless network. In a BSS, the AP is used to periodically send beacon frames, and in an IBSS, the STAs within the IBSS rotate to send beacon frames. When the STA performing the scanning receives a beacon frame, the STA stores the information of the BSS included in the beacon frame, and while moving to another channel, records the beacon frame information in each channel. The 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 in the next channel in the same way. Comparing active scanning with passive scanning, the advantage of active scanning is that it has less latency and less power consumption than passive scanning.

[0073] After the STA discovers the network, an authentication process can be performed in step S320. To clearly distinguish it from the security establishment operation in step S340 to be described later, this authentication process can be referred to as the first authentication process.

[0074] The authentication process includes the following processing: The STA sends an authentication request frame to the AP, and in response thereto, the AP sends an authentication response frame to the STA. The authentication frame for authentication request / response corresponds to a management frame.

[0075] The authentication frame includes an authentication algorithm number, an authentication transaction serial number, a status code, a challenge text, a Robust Security Network (RSN), a finite cyclic group, etc. This corresponds to some examples of information that can be included in the authentication request / response frame, and can be replaced with other information, or additional information can also be included.

[0076] The STA can send an authentication request frame to the AP. The AP can determine whether to allow the authentication of the corresponding STA based on the information included in the received authentication request frame. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0077] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the following processes: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0078] For example, the association request frame can include information related to various capabilities, a beacon listening interval, a Service Set Identifier (SSID), supported rates, supported channels, RSN, a mobility domain, supported operation classes, a Traffic Indication Map Broadcast Request (TIM broadcast request), an interworking service capability, etc. For example, the association response frame can include information related to various capabilities, a status code, an Association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal-to-Noise Ratio Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association recovery time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. This corresponds to some examples of information that can be included in the association request / response frame, and can be replaced with other information, or additional information can also be included.

[0079] After the STA is successfully associated with the network, the security establishment process can be performed in step S340. The security establishment process in step S340 can be referred to as an authentication process through Robust Security Network Association (RSNA) request / response. The authentication process in step S320 is referred to as the first authentication process, and the security establishment process in step S340 can also simply be referred to as an authentication process.

[0080] The security establishment process in step S340 can, for example, include a process of establishing a private key using the Extensible Authentication Protocol over LAN (EAPOL) frame through a four-way handshake. Additionally, the security establishment process can be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0081] Figure 4 It is a diagram for explaining the backoff process to which the present disclosure can be applied.

[0082] In a wireless LAN system, the basic access mechanism of the Media Access Control (MAC) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also referred to as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC and basically adopts a "listen before talk" access mechanism. According to this type of access mechanism, before starting to transmit, the AP and / or STA can perform a Clear Channel Assessment (CCA) of sensing the radio channel or medium during a predetermined time interval (e.g., the DCF Interframe Space (DIFS)). As a result of the sensing, if it is determined that the medium is idle, frame transmission is started through the corresponding medium. On the other hand, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not start its own transmission and can set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after waiting. By applying the random backoff period, since it is expected that multiple STAs will attempt frame transmission after waiting for different time periods, collisions can be minimized.

[0083] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method and refers to the method in which all receiving APs and / or STAs are periodically polled to receive data frames. In addition, the HCF has an Enhanced Distributed Channel Access (EDCA) and an HCF Control Channel Access (HCCA). The EDCA is a contention-based access method that provides data frames to multiple users in a direction, and the HCCA uses a contention-free channel access method that utilizes a polling mechanism. In addition, the HCF includes a medium access mechanism for improving the Quality of Service (QoS) of the wireless LAN and can transmit QoS data during a Contention Period (CP) and a Contention-Free Period (CFP).

[0084] Refer to Figure 4, operations based on a random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs can attempt to transmit data (or frames). As a method to minimize collisions, each of the STAs can separately select a random backoff count and attempt transmission after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values that vary from 0 to the value of CW. Here, CW is the contention window parameter value. The CW parameter is given the initial value of CWmin, but can take a value twice as large in the case of a transmission failure (e.g., when an ACK for the transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until the data transmission is successful, and when the data transmission is successful, the CWmin value is reset. The values of CW, CWmin, and CWmax are preferably set to 2n - 1 (n = 0, 1, 2,...).

[0085] When the random backoff process starts, the STA continuously monitors the medium during the countdown of the backoff slot according to the determined backoff count value. When monitoring the medium for occupancy, it stops the countdown and waits, and when the medium becomes idle, it resumes the remaining part of the countdown.

[0086] In Figure 4 the example, when the packet to be transmitted arrives at the MAC of STA3, STA3 can transmit the frame immediately after confirming that the medium has been idle for up to DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. At the same time, the data to be transmitted can also occur in each of STA1, STA2, and STA5, and when the medium is monitored as idle, each STA waits for up to DIFS and then can perform the countdown of the backoff slot according to the random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, an example is shown where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 completes the backoff count and starts frame transmission. STA1 and STA5 temporarily stop the countdown and wait while STA2 occupies the medium. When the occupancy of STA2 ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and resume the stopped backoff count. That is, frame transmission can start after counting down the remaining backoff slots for the remaining backoff time. Since the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1, STA5 starts frame transmission. When STA2 occupies the medium, the data to be transmitted can also occur in STA4. From the perspective of STA4, when the medium becomes idle, STA4 can wait for DIFS and then can perform the countdown according to the random backoff count value selected by STA4 and start transmitting the frame. Figure 4The example shows a situation where the remaining backoff time of STA5 accidentally conflicts with the random backoff counter value of STA4. In this case, a conflict may occur between STA4 and STA5. When a conflict occurs, neither STA4 nor STA5 receives an ACK, so the data transmission fails. In this case, STA4 and STA5 can double the CW value, select a random backoff counter value, and perform countdown. When the medium is occupied due to the transmissions of STA4 and STA5, STA1 waits. When the medium becomes idle, STA1 waits for the DIFS, and then starts frame transmission after the remaining backoff time has passed.

[0087] As in Figure 4 the example, a data frame is a frame for transmitting data forwarded to a higher layer, and can be transmitted after a backoff performed after the medium becomes idle and after DIFS has elapsed. Additionally, a management frame is a frame for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff performed after an IFS such as DIFS or Point Coordination Function IFS (PIFS). As sub - type frames of the management frame, there are beacons, association request / response, re - association request / response, probe request / response, authentication request / response, etc. A control frame is a frame for controlling access to the medium. As sub - type frames of the control frame, there are Request to Send (RTS), Clear to Send (CTS), Acknowledgment (ACK), Power - Save Poll (PS - Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP Announcement), and Trigger, etc. If a control frame is not a response frame to a previous frame, it is transmitted after a backoff performed after DIFS has elapsed, and if it is a response frame to a previous frame, it is transmitted without performing a backoff after Short IFS (SIFS) has elapsed. The type and sub - type of a frame can be identified by the type field and sub - type field in the Frame Control (FC) field.

[0088] A Quality of Service (QoS) STA can perform a backoff performed after Arbitration IFS (AIFS) for the access category (AC) to which the frame belongs (i.e., AIFS (where i is a value determined by the AC)), and then can transmit the frame. Here, frames for which AIFS can be used can be data frames, management frames, or control frames other than response frames.

[0089] Figure 5 is a diagram for explaining the CSMA / CA - based frame transmission operation to which the present disclosure can be applied.

[0090] As described above, in addition to the physical carrier sensing of the medium directly by the STA, the CSMA / CA mechanism also includes virtual carrier sensing. The virtual carrier sensing aims to compensate for problems such as the hidden node problem that may occur in medium access. For virtual carrier sensing, the MAC of the STA can use the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the remaining time until the medium is available for use by the STA that currently has the right to use the medium. Therefore, the value set as the NAV corresponds to the period during which the STA that transmits the frame plans to use the medium, and during the corresponding period, the STA that receives the NAV value is prohibited from accessing the medium. For example, the NAV can be configured based on the value of the "Duration" field in the MAC header of the frame.

[0091] In Figure 5 the example, it is assumed that STA1 aims to send data to STA2, and STA3 is in a position where it can overhear some or all of the frames transmitted and received between STA1 and STA2.

[0092] To reduce the possibility of transmission collisions of multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames can be applied. In Figure 5 the example, when the transmission of STA1 is being executed, as a result of the carrier sensing of STA3, it can be determined that the medium is in an idle state. That is, STA1 can correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 the example, it can be determined that when the transmission of STA2 is being executed, the carrier sensing result of STA3 indicates that the medium is in an idle state. That is, STA2 can correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before the data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2 or STAs outside the carrier sensing range of the transmission from STA1 or STA3 can refrain from attempting to occupy the channel during the data transmission and reception between STA1 and STA2.

[0093] Specifically, STA1 can determine whether the channel is being used through carrier sensing. In terms of physical carrier sensing, STA1 can determine the occupied or idle state of the channel based on the energy level or signal correlation detected in the channel. Additionally, in terms of virtual carrier sensing, STA1 can use the Network Allocation Vector (NAV) timer to determine the channel occupancy state.

[0094] When the channel is in an idle state during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0095] If STA3 cannot overhear the CTS frame from STA2 but can overhear the RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the transmission period of the frames continuously sent thereafter (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 can overhear the CTS frame from STA2, even though STA3 cannot overhear the RTS frame from STA1, STA3 can also use the duration information included in the CTS frame to set the NAV timer for the transmission period of the frames continuously sent thereafter (e.g., SIFS + data frame + SIFS + ACK frame). That is to say, if STA3 can overhear one or more of the RTS frames or CTS frames from one or more of STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the expiration of the NAV timer, STA3 can use the duration information included in the new frame to update the NAV timer. STA3 does not attempt channel access until the NAV timer expires.

[0096] When STA1 receives the CTS frame from STA2, STA1 can send a data frame to STA2 after SIFS from the time point when the reception of the CTS frame is completed. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 can determine whether the channel is being used through carrier sensing. When STA3 determines during the DIFS period after the expiration of the NAV timer that the channel is not being used by other terminals, STA3 can attempt channel access after the contention window (CW) according to random backoff has elapsed.

[0097] Figure 6 It is a diagram for explaining an example of the frame structure used in a WLAN system to which the present disclosure can be applied.

[0098] With instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MAC PDU (MPDU) to be transmitted. For example, when receiving a command from the MAC layer to start transmission from the PHY layer, the PHY layer switches to the transmission mode, configures the information (e.g., data) provided by the MAC layer in the form of a frame, and transmits it. Additionally, when the PHY layer detects the valid preamble of the received frame, the PHY layer monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception by the PHY layer.

[0099] In this way, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, a PHY layer protocol data unit (PPDU) format is defined.

[0100] The basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., Figure 7 the non-HT (High Throughput) shown in

[0101] can consist only of a legacy-STF (L-STF), a legacy-LTF (L-LTF), a legacy-SIG (L-SIG) field, and a Data field. Additionally, depending on the type of PPDU format (e.g., HT Mixed format PPDU, HT Greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) etc. can be included between the L-SIG field and the Data field.

[0102] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits, and the L-SIG field may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may include information about the modulation and coding rate of the data. For example, the 12-bit Length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit Length field can be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDU, the value of the Length field can be determined to be a multiple of 3. For example, for HE PPDU, the value of the Length field can be determined to be a multiple of 3 + 1 or 3 + 2.

[0103] The data field may include a SERVICE field, a Physical Layer Service Data Unit (PSDU), and PPDU tail bits, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bits may be used to return the encoder to the 0 state. The padding bits may be used to adjust the length of the data field in predetermined units.

[0104] The MAC PDU is defined according to various MAC frame formats, and the basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). The MAC frame may be composed of MAC PDUs and transmitted / received through the PSDU of the data part in the PPDU format.

[0105] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the corresponding frame, etc. For details of the Sequence Control, QoS Control, and HT Control sub-fields of the MAC header, refer to the IEEE 802.11 standard document.

[0106] The Null Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, the NDP refers to a frame format that includes the PPDU preamble of the general PPDU format (i.e., the L-STF, L-LTF, L-SIG fields, and additional non-conventional SIG, non-conventional STF, non-conventional LTF (if any)) and does not include the remainder (i.e., the data field).

[0107] Figure 7 is a diagram illustrating an example of the PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0108] In standards such as IEEE 802.11a / g / n / ac / ax, various types of PPDUs have been used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and a data field. The basic PPDU format may also be referred to as the non-HT PPDU format (as shown in (a) of Figure 7 .

[0109] Compared with the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields. Figure 7The HT PPDU format shown in (b) can be referred to as the HT mixed format. Additionally, an HT greenfield format PPDU can be defined, and this corresponds to a format (not shown) consisting of an HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a data field, excluding the L-STF, L-LTF, and L-SIG.

[0110] Compared with the basic PPDU format, an example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (as Figure 7 shown in (c)).

[0111] Compared with the basic PPDU format, an example of the HE PPDU format (IEEE 802.11ax) additionally includes a repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, and packet extension (PE) fields (as Figure 7 shown in (d)). Some fields can be excluded, or their lengths can vary according to the detailed example of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single-user (SU). Additionally, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field can vary up to 8 μs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary up to 16 μs. For example, the RL-SIG can be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA can know that the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0112] The EHT PPDU format can include Figure 7 the EHT MU (multi-user) in (e) and Figure 7 the EHT TB (trigger-based) PPDU in (f). The EHT PPDU format is similar to the HE PPDU format in including an RL-SIG following the L-SIG, but can include a U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0113] Figure 7The EHT MU PPDU in (e) corresponds to a PPDU carrying one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0114] Compared with the EHT MU PPDU, Figure 7 the EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or a triggered response scheduling (TRS)) can perform UL transmission based on the EHT TB PPDU format.

[0115] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), EHT-SIG fields can be encoded and modulated so that even traditional STAs can attempt to demodulate and decode, and can be mapped based on the determined subcarrier frequency spacing (e.g., 312.5 kHz). These can be called pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, data, PE fields can be encoded and modulated to be demodulated and decoded by a STA that has successfully decoded a non-traditional SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information included in this field, and can be mapped based on the determined subcarrier frequency spacing (e.g., 78.125 kHz). These can be called EHT modulation fields.

[0116] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be called pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields can be called HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be called VHT-free modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields can be called VHT modulation fields.

[0117] Included in Figure 7The U-SIG in the EHT PPDU format can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 μs, and the U-SIG can have a total duration of 8 μs. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0118] The U-SIG can be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG can be replicated. That is, the same 4 U-SIGs can be included in the 80 MHz PPDU. A PPDU with a bandwidth exceeding 80 MHz can include different U-SIGs.

[0119] For example, A uncoded bits can be transmitted through the U-SIG. The first symbol of the U-SIG (e.g., U-SIG-1 symbol) can transmit the first X bits of information out of a total of A bits of information, and the second symbol of the U-SIG (e.g., U-SIG-2 symbol) can transmit the remaining Y bits of information out of a total of A bits of information. The A bits of information (e.g., 52 uncoded bits) can include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). For example, the tail field can be used to terminate the trellis structure of the convolutional decoder and can be set to 0.

[0120] The bit information transmitted through the U-SIG can be divided into version-independent bits and version-dependent bits. For example, the U-SIG can be included in Figure 7 a new PPDU format (e.g., UHR PPDU format) not shown, and can be included in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format. The version-independent bits can be the same, and some or all of the version-dependent bits can be different.

[0121] For example, the size of the version-independent bits of the U-SIG can be fixed or variable. The version-independent bits can be assigned only to the U-SIG-1 symbol, or assigned to both the U-SIG-1 symbol and the U-SIG-2 symbol. The version-independent bits and the version-dependent bits can be called various names, such as the first control bit and the second control bit.

[0122] For example, the version-independent bits of the U-SIG may include 3-bit physical layer version identifiers (PHY version identifiers), and this information may indicate the PHY version of the transmitted / received PPDU (e.g., EHT, UHR, etc.). The version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field is associated with UL communication, and the second value of the UL / DL flag field is associated with DL communication. The version-independent bits of the U-SIG may include information about the length of the transmit opportunity (TXOP) and information about the BSS color ID.

[0123] For example, the version-dependent bits of the U-SIG may include information that directly or indirectly indicates the type of the PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0124] The information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may also include information about the bandwidth, information about the MCS technique applied to non-traditional SIGs (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether the DCM (dual carrier modulation) technique (e.g., a technique for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to non-traditional SIGs, information about the number of symbols for non-traditional SIGs, information about whether non-traditional SIGs are generated across the entire frequency band.

[0125] Some of the information required for PPDU transmission and reception may be included in the U-SIG and / or non-traditional SIGs (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of non-traditional LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-traditional LTF and the CP (cyclic prefix) length, information about the GI (guard interval) applicable to the non-traditional LTF, information about the preamble puncturing applicable to the PPDU, information about the resource unit (RU) allocation, etc. may be included only in the U-SIG, included only in the non-traditional SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-traditional SIG.

[0126] Preamble puncturing may represent the transmission of the following PPDU, where there is no signal in one or more frequency units among the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or larger.

[0127] In Figure 7In an example, non - traditional SIGs such as HE - SIG - B and EHT - SIG can include control information for receiving STAs. The non - traditional SIG can be sent on at least one symbol, and one symbol can have a length of 4 μs. Information about the number of symbols for EHT - SIG can be included in a previous SIG (e.g., HE - SIG - A, U - SIG, etc.).

[0128] Non - traditional SIGs such as HE - SIG - B and EHT - SIG can include a common field and user - specific fields. The common field and user - specific fields can be encoded separately.

[0129] In some cases, the common field can be omitted. For example, in a compressed mode that does not apply OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive a PPDU (e.g., the data field of the PPDU) through the same frequency band. In a non - compressed mode that applies OFDMA, multiple users can receive a PPDU (e.g., the data field of the PPDU) through different frequency bands.

[0130] The number of user - specific fields can be determined based on the number of users. One user block field can include up to two user fields. Each user field can be associated with MU - MIMO allocation or can be associated with non - MU - MIMO allocation.

[0131] The common field can include CRC bits and tail bits. The length of the CRC bits can be determined to be 4 bits, and the length of the tail bits can be determined to be 6 bits and set to 000000. The common field can include RU allocation information. The RU allocation information can include information about the positions of the RUs assigned to multiple users (i.e., multiple receiving STAs).

[0132] An RU can include multiple sub - carriers (or tones). When sending signals to multiple STAs based on OFDMA technology, RUs can be used. Additionally, even when sending signals to one STA, RUs can be defined. Resources can be allocated for non - traditional STF, non - traditional LTF, and data fields in units of RUs.

[0133] The RU of an applicable size can be defined according to the PPDU bandwidth. The RU can be defined identically or differently for the applied PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU layout of the HE PPDU and the EHT PPDU can be different. The applicable RU size, the number and position of RUs, the DC (direct current) subcarrier position and number, the null subcarrier position and number, the guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, the tone plan for high bandwidth can be defined in the form of multiple iterations of a low bandwidth tone plan.

[0134] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. An MRU (multi-RU) is different from multiple individual RUs and corresponds to a set of subcarriers composed of multiple RUs. For example, an MRU can be defined as 52 + 26 tones, 106 + 26 tones, 484 + 242 tones, 996 + 484 tones, 996 + 484 + 242 tones, 2×996 + 484 tones, 3×996 tones, or 3×996 + 484 tones. Additionally, the multiple RUs that make up an MRU can be continuous or non-continuous in the frequency domain.

[0135] The specific size of an RU can be reduced or extended. Therefore, the specific size (i.e., the number of corresponding tones) of each RU in this disclosure is illustrative rather than restrictive. Additionally, in this disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz...), the number of RUs can vary according to the RU size.

[0136] Figure 7 The name of each field in the PPDU format is exemplary, and the scope of this disclosure is not limited by these names. Additionally, the examples of this disclosure can be applied to Figure 7 the PPDU format shown in Figure 7 and new PPDU formats that exclude some fields and / or add some fields based on the

[0137] Resource unit

[0138] Figures 8 to 10 is a diagram for illustrating an example of a resource unit of a WLAN system to which this disclosure can be applied.

[0139] Refer to Figures 8 to 10, a resource unit (RU) defined in a wireless LAN system will be described. An RU may include a plurality of subcarriers (or tones). When transmitting signals to multiple STAs based on the OFDMA scheme, an RU can be used. Additionally, even when a signal is transmitted to one STA, an RU can be defined. An RU can be used for the data field, STF, LTF, etc. of a PPDU.

[0140] As Figures 8 to 10 shown in, RUs corresponding to different numbers of tones (i.e., subcarriers) are used to construct some fields of 20 MHz, 40 MHz, or 80 MHz X-PPDU (X is HE, EHT, etc.). For example, resources can be allocated in RU units shown for the X-STF, X-LTF, and data fields.

[0141] Figure 8 is a diagram illustrating an exemplary allocation of resource units (RUs) used in a 20 MHz frequency band.

[0142] As Figure 8 shown at the top of, a 26-unit (i.e., a unit corresponding to 26 tones) can be allocated. Six tones can be used as a guard band in the leftmost frequency band of the 20 MHz frequency band, and five tones can be used as a guard band in the rightmost frequency band of the 20 MHz frequency band. Additionally, seven DC tones are inserted into the center frequency band (i.e., the DC band), and 26-units corresponding to each of the 13 tones can exist on the left and right sides of the DC band. Additionally, 26-units, 52-units, and 106-units can be allocated to other frequency bands. Each unit can be allocated to an STA or a user.

[0143] Figure 8 The RU allocation of is used not only for the multi-user (MU) case but also for the single-user (SU) case, and in this case, one 242-unit can be used, as Figure 8 shown at the bottom of. In this case, three DC tones can be inserted.

[0144] In Figure 8 's example, various sizes of RUs are exemplified, that is, 26-RU, 52-RU, 106-RU, 242-RU, etc., but the specific sizes of these RUs can be reduced or enlarged. Therefore, in this disclosure, the specific size of each RU (i.e., the number of corresponding tones) is exemplary and not restrictive. Additionally, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz,...) in this disclosure, the number of RUs can vary according to the size of the RU. In what will be described below Figure 9 and / or Figure 10In the example, the fact that the size and / or number of RUs can vary is the same as in Figure 8 the example.

[0145] Figure 9 is a diagram illustrating an exemplary allocation of resource units (RUs) used in a 40 MHz frequency band.

[0146] Just as various sizes of RUs are used in the example of Figure 8 , 26-RUs, 52-RUs, 106-RUs, 242-RUs, 484-RUs, etc. can also be used in the example of Figure 9 . Additionally, 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 frequency band, and 11 tones can be used as a guard band in the rightmost band of the 40 MHz frequency band.

[0147] Additionally, as shown, when used for a single user, a 484-RU can be used.

[0148] Figure 10 is a diagram illustrating an exemplary allocation of resource units (RUs) used in an 80 MHz frequency band.

[0149] Just as various sizes of RUs are used in the examples of Figure 8 and Figure 9 , 26-RUs, 52-RUs, 106-RUs, 242-RUs, 484-RUs, 996-RUs, etc. can also be used in the example of Figure 10 . Additionally, in the case of an 80 MHz PPDU, the RU allocation for HE PPDU and EHT PPDU can be different, and Figure 10 the example shows an example of RU allocation for an 80 MHz EHT PPDU. Figure 10 The scheme in the example of where 12 tones are used as a guard band in the leftmost band of the 80 MHz frequency band and 11 tones are used as a guard band in the rightmost band of the 80 MHz frequency band is the same in HE PPDU and EHT PPDU. Different from the HE PPDU where 7 DC tones are inserted in the DC band and there is one 26-RU corresponding to each of the 13 tones on the left and right sides of the DC band, in the EHT PPDU, 23 DC tones are inserted in the DC band, and there is one 26-RU on the left and right sides of the DC band. Different from the HE PPDU where one empty subcarrier exists between 242-RUs instead of the center band, in the EHT PPDU, there are five empty subcarriers. In the HE PPDU, one 484-RU does not include empty subcarriers, but in the EHT PPDU, one 484-RU includes 5 empty subcarriers.

[0150] In addition, as shown, when used for a single user, 996-RU can be used, and in this case, 5 DC tones are inserted, as with HEPPDU and EHT PPDU.

[0151] In Figure 10 an EHT PPDU on 160 MHz can be configured with multiple 80 MHz sub-blocks. The RU allocation for each 80 MHz sub-block can be the same as the RU allocation for an Figure 10 80 MHz EHT PPDU. If the 80 MHz sub-block of a 160 MHz or 320 MHz EHT PPDU is not punctured and the entire 80 MHz sub-block is used as part of an RU or multiple RUs (MRUs), the 80 MHz sub-block can use the Figure 10 996-RU of

[0152] Here, an MRU corresponds to a set of subcarriers (or tones) composed of multiple RUs, and the multiple RUs that make up an MRU can be RUs of the same size or RUs of different sizes. For example, a single MRU can be defined as 52+26-tone, 106+26-tone, 484+242-tone, 996+484-tone, 996+484+242-tone, 2×996+484-tone, 3×996-tone, or 3×996+484-tone. Here, the multiple RUs that make up an MRU can correspond to small-size (e.g., 26, 52, or 106) RUs or large-size (e.g., 242, 484, or 996) RUs. That is, an MRU including both small-size RUs and large-size RUs may not be configured / defined. In addition, the multiple RUs that make up an MRU can be continuous or non-continuous in the frequency domain.

[0153] When an 80 MHz sub-block includes an RU with less than 996 tones or a part of the 80 MHz sub-block is punctured, the 80 MHz sub-block can use an RU allocation other than the 996-tone RU.

[0154] The RU of the present disclosure can be used for uplink (UL) and / or downlink (DL) communications. For example, when performing trigger-based UL-MU communication, the transmitting trigger STA (e.g., AP) can allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a second STA via trigger information (e.g., a trigger frame or a trigger response schedule (TRS)). Thereafter, the first STA can send a first trigger-based (TB) PPDU based on the first RU, and the second STA can send a second TB PPDU based on the second RU. The first / second TB PPDUs can be sent to the AP within the same time period.

[0155] For example, when configuring a DL MU PPDU, the STA (e.g., AP) that transmits the DL MU PPDU can allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a second STA. That is, the transmitting STA (e.g., AP) can send an X-STF (e.g., X represents HE, EHT, etc.), an X-LTF, and a data field for the first STA within one MU PPDU via the first RU, and can send an X-STF, an X-LTF, and a data field for the second STA via the second RU. Information regarding RU assignment can be signaled via the X-SIG (e.g., X represents HE, EHT, U) field in the X-PPDU format.

[0156] Method for considering supporting millimeter wave (mmWave) frequency band to perform beamforming training process

[0157] The description of the above wireless LAN system can mainly be applied to a wireless LAN system operating in an existing operating frequency band (e.g., a frequency band below 7 GHz, such as the 2.4 GHz, 5 GHz, or 6 GHz frequency band). For example, the above PPDU format can mainly be applied to a wireless LAN system operating in a frequency band below 7 GHz. Additionally, a wireless LAN system operating in a high operating frequency band (e.g., a millimeter wave (mmWave) frequency band, such as the 60 GHz frequency band) has been defined.

[0158] The present disclosure describes an example of a beamforming training process that considers improved throughput and efficiency in the mmWave frequency band (including (i.e., not limited to) the 60 GHz frequency band).

[0159] Figure 11 is a diagram showing an example of a region where channelization of the millimeter wave (mmWave) frequency band to which the present disclosure can be applied.

[0160] Figure 11The example in shows the mmWave bands used in the United States, the European Union, South Korea, Japan, Australia, and China, and shows the channel sizes and positions defined in these bands. For example, the bandwidth of each of the six channels can correspond to 2.16 GHz. In addition, when bandwidth binding is applied, up to four unit bandwidths can be bound to support a bandwidth of up to 8.64 GHz.

[0161] Different from these existing wireless LAN systems, technologies such as UHR being discussed are considering using sub-7 GHz bands (e.g., 2.4 GHz, 5 GHz, or 6 GHz bands) and / or mmWave bands (e.g., 60 GHz band) to achieve high data rates and low latency. For example, for specific use cases that require high throughput, it may be difficult to meet the requirements only using the currently defined channel bandwidths, so it may be considered to send / receive specific PPDUs through the mmWave band.

[0162] However, since the signal has strong directivity in the mmWave band, it is greatly affected by obstacles, etc., and thus, signal attenuation may occur very significantly.

[0163] Therefore, in order to overcome these problems, analog beamforming using a directional antenna may be necessary. In this case, a sector-level scan (SLS) process and a beam refinement protocol (BRP) process, which are beamforming training processes, may be required.

[0164] In the present disclosure, SLS processes and BRP processes for beam training in a next-generation wireless LAN system (e.g., UHR, etc.) capable of supporting the mmWave band are proposed.

[0165] In this regard, although the SLS processes and BRP processes assuming the SISO case are proposed / described in the present disclosure, the methods proposed in the present disclosure can also be extended and applied to the MIMO case.

[0166] As described above, the beam training process may include an SLS phase corresponding to the SLS process and a BRP phase corresponding to the BRP process.

[0167] At this time, the station that initiates the beam training process may be referred to as the initiator, and the corresponding station (e.g., the paired station) may be referred to as the responder. For example, an AP, a PCP, etc. can be configured / assigned as the initiator of the beam training process, and a non-AP STA, etc. can be configured / assigned as the responder.

[0168] In this regard, for beam training, the initiator and / or the responder can perform a transmit sector scan and / or a receive sector scan.

[0169] For the method proposed in the present disclosure, the term sector may be replaced by a term having the same / similar technical meaning, such as region, direction, antenna configuration, or antenna weight vector.

[0170] The embodiments in the present disclosure will be described below as representative examples, where the initiator of the beam training process is the AP and the responder is the STA (e.g., non-AP STA).

[0171] Embodiment 1

[0172] This embodiment is a method for performing sector-level scanning (SLS) process in a wireless LAN system supporting the mmWave band.

[0173] First, the TX sector scanning method of the AP will be described.

[0174] For sector scanning, the AP may periodically (e.g., the transmission period of the beacon) send a burst of specific PPDU / frames on a specific channel within a specific time period. Here, the burst may represent a unit composed of (consecutive) multiple PPDU / frames.

[0175] For example, the specific time and specific channel may correspond to the specific time and frequency resources allocated / assigned for the beam training process in the mmWave band.

[0176] Each PPDU / frame included in the burst is sent in a specific direction, and a specific sector ID may be assigned to each PPDU / frame.

[0177] In this regard, the specific PPDU / frame may act as a beacon. In this case, the specific PPDU / frame may include / carry various information other than sector scanning, such as a conventional beacon frame. Alternatively, the specific PPDU / frame may correspond to a PPDU / frame that only includes information for sector scanning. In this case, the specific PPDU / frame may be defined to include only simple information such as the sector ID, and other information may be defined to be indicated in another operating band (e.g., below 7 GHz band).

[0178] At this time, the number of PPDU / frames sent within the aforementioned burst may be fixed. Alternatively, the number of PPDU / frames sent within the burst is not fixed, and 1-bit information within the PPDU / frame may be used to indicate information indicating whether the corresponding PPDU / frame corresponds to the last PPDU / frame of the burst (e.g., corresponds to the last PPDU / frame or there are remaining PPDU / frames to be sent).

[0179] Additionally or alternatively, sector scanning between the AP and a specific STA may be performed by allocating specific time and / or frequency resources (such as by transmitting control / management frames in a sub-7 GHz band).

[0180] Also in this case, as in the foregoing method, the PPDU / frame is sent in a burst format, and each PPDU / frame may be sent in corresponding time and / or frequency resources in a specific direction. In this regard, burst transmission may be performed by considering only some sector candidates using prior information.

[0181] At this time, the number of PPDU / frames sent within the foregoing burst may be fixed. Alternatively, the number of PPDU / frames sent within the burst is not fixed, and 1-bit information within the PPDU / frame may be used to indicate information indicating whether the corresponding PPDU / frame corresponds to the last PPDU / frame of the burst (e.g., corresponds to the last PPDU / frame or there are remaining PPDU / frames to be sent). Alternatively, the number of PPDU / frames sent within the burst may also be indicated by, for example, the transmission of frames in a sub-7 GHz band.

[0182] Next, a TX sector scanning method of the STA will be described.

[0183] Similar to the foregoing TX sector scanning method of the AP, the STA may also send a burst of specific PPDU / frames. At this time, after the TX sector scanning of the AP, the STA may send a burst of corresponding PPDU / frames on the same channel (or sub-channel).

[0184] Even in this case, each PPDU / frame included in the burst is sent in a specific direction, and a specific sector ID may be assigned to each PPDU / frame. Here, information about the specific sector ID may be indicated in each PPDU / frame.

[0185] Additionally, the number of PPDU / frames sent within the foregoing burst may be fixed. Alternatively, the number of PPDU / frames sent within the burst is not fixed, and 1-bit information within the PPDU / frame may be used to indicate information indicating whether the corresponding PPDU / frame corresponds to the last PPDU / frame of the burst (e.g., corresponds to the last PPDU / frame or there are remaining PPDU / frames to be sent).

[0186] If the sub-7 GHz band is not managed, multiple STAs may attempt sector scanning, which may cause a collision. Therefore, it may be desirable to allocate specific time and / or frequency resources for TX sector scanning to each STA in the sub-7 GHz.

[0187] Additionally or alternatively, a method that utilizes antenna pattern reciprocity may be considered to reduce overhead and simplify the process.

[0188] For example, when performing a TX sector scan of an AP, a specific training field (e.g., the TRN field used in an EDMG BRP RX packet, etc.) may be inserted at the end of a PPDU so that a STA can perform an RX sector scan. In this case, the TX sector scan of the STA can be omitted by utilizing reciprocity, and the STA can use the best RX sector as the best TX sector. Similarly, the AP can also use the best TX sector as the best RX sector, and thus, an additional RX sector scan in the AP may not be required.

[0189] Hereinafter, Figures 12 to 14 the SLS process described in the present embodiment will be specifically described.

[0190] Figure 12 An example of the SLS process between an AP and a STA according to an embodiment of the present disclosure is illustrated.

[0191] Referring to Figure 12 , for the SLS process between an AP and a STA, the SLS initiation can be configured / defined to be performed in a sub-7 GHz band, and the remaining operations can be performed in a mmWave band.

[0192] First, the SLS initiation (S1210) can be performed for the AP and the STA in the sub-7 GHz band.

[0193] For example, regarding the sector scan and the transmission of feedback / ACK frames in the SLS process, information indicating the allocation of specific time and / or frequency resources (e.g., channels, sub-channels), information regarding the number of PPDUs / frames in a burst of PPDUs / frames, etc. can be indicated. Here, the PPDU / frame can correspond to a packet related to the sector scan (e.g., an SSW packet).

[0194] In this regard, the specific time and / or frequency resources can be resources allocated for operations in the mmWave band.

[0195] The AP can send a burst of specific PPDUs / frames (S1220) in the allocated time and / or frequency resources.

[0196] In this regard, each PPDU / frame included in the burst can include information on the sector ID indicating the transmission direction.

[0197] At this time, the STA can use the corresponding PPDU / frame to measure the best TX sector ID (S1230) of the AP. In this case, the STA can receive a burst of specific PPDUs / frames in the quasi-omnidirectional mode.

[0198] Here, the best TX sector ID can be configured in the form of a list including one or more TX sector IDs.

[0199] After the burst transmission of the AP, the STA can send a burst of specific PPDUs / frames (S1240) on the allocated time and / or frequency resources or on the same frequency resource after a certain period (e.g., SIFS) after the end of the burst transmission of the AP.

[0200] In this regard, each PPDU / frame included in the burst can include information on the sector ID indicating the transmission direction. At the same time, the STA can feedback information on the best TX sector ID of the AP to the AP.

[0201] At this time, the AP can use the corresponding PPDU / frame to measure the best TX sector ID of the STA (S1250). In this case, the AP can receive a burst of specific PPDUs / frames in the quasi-omnidirectional mode.

[0202] After the burst transmission of the STA, the AP can send a feedback frame (S1260) to the STA on the allocated time and / or frequency resources or on the same frequency resource after a certain time (e.g., SIFS) after the end of the burst transmission of the STA according to the best TX sector direction feedback by the STA. Here, the feedback frame can include information on the best TX sector ID of the STA. For example, the STA can receive the feedback frame in the quasi-omnidirectional mode.

[0203] Next, the STA can send a response frame (e.g., ACK frame) (S1270) on the same frequency resource and / or on the allocated time and / or frequency resources after a specific period (e.g., SIFS) after the end of the transmission of the feedback frame of the AP according to the best TX sector direction feedback by the AP. For example, the STA can receive the feedback frame in the quasi-omnidirectional mode.

[0204] Regarding the foregoing Figure 12 In the steps, step S1210 can be set / defined to be executed in the sub-7GHz band, and the remaining steps (i.e., steps S1220 to S1270) can be configured / defined to be executed in the mmWave band.

[0205] Figure 13 Another example of the SLS process between the AP and the STA according to an embodiment of the present disclosure is illustrated.

[0206] Refer toFigure 13 , compared with Figure 12 , the SLS process can be simplified by leveraging antenna pattern reciprocity as described above in the present disclosure.

[0207] First, SLS initiation (S1310) can be performed for the AP and STA in the sub-7 GHz band.

[0208] For example, regarding sector scanning and transmission of feedback / ACK frames in the SLS process, information indicating allocation of specific time and / or frequency resources (e.g., channels, sub-channels), information regarding the number of PPDUs / frames in a burst of PPDUs / frames, etc. can be indicated. Here, the PPDU / frame can correspond to a packet related to sector scanning (e.g., SSW packet).

[0209] In this regard, the specific time and / or frequency resources can be resources allocated for operation in the mmWave band.

[0210] The AP can transmit a burst of specific PPDUs / frames in the allocated time and / or frequency resources (S1320).

[0211] In this regard, each PPDU / frame included in the burst can include information of the sector ID indicating the transmission direction.

[0212] At this time, the STA can use the PPDUs / frames included in the burst to measure the best TX sector ID of the AP and perform its own RX sector scanning (S1330).

[0213] In this regard, a specific training field (TRN field) can be defined to be included in the last part of the corresponding PPDU / frame to support the RX sector scanning of the STA. For example, the specific training field can be designed to have the same or similar structure as the TRN field of the EDMG BRP-RX / TXPPDU, TRN-R unit, etc.

[0214] Specifically, the STA performs reception operations in the quasi-omnidirectional mode only during the TX sector scanning of the AP, and can be configured / defined to operate in the RX sector scanning mode only for the specific training field.

[0215] After the burst transmission of the AP, the STA can use the allocated time and / or frequency resources or at a certain time after the burst transmission of the AP is completed (e.g., SIFS) to send a feedback frame to the AP in the same TX direction using its best RX sector in the same frequency resource (S1340). Here, the feedback frame can include information regarding the best TX sector ID of the AP. For example, the AP can receive the feedback frame in the quasi-omnidirectional mode.

[0216] Next, the AP may send a response frame (e.g., an ACK frame) on the same frequency resource according to the best TX sector direction fed back by the STA at the assigned time and / or frequency resource or after a specific period of time (e.g., SIFS) after the STA's feedback frame transmission ends (S1350). For example, the STA may receive the feedback frame according to its best RX sector direction.

[0217] In such Figure 13 In the simplified process in , the STA can use its measured best RX sector in the TX sector direction, and the AP can use its best TX sector fed back from the STA in the RX sector direction.

[0218] Additionally or alternatively, in the above Figure 12 and Figure 13 In the process of transmitting a burst of PPDU / frames, the sector ID and its sequence information may be indicated in the sub-7 GHz band. In this case, the information may be defined as not being indicated in each PPDU / frame within the burst.

[0219] Regarding the aforementioned Figure 13 In the steps, step S1310 can be set / defined to be performed in the frequency band below 7 GHz, and the remaining steps (i.e., steps S1320 to S1350) can be configured / defined to be performed in the mmWave frequency band.

[0220] Figure 14 Another example of the SLS procedure between the AP and the STA according to an embodiment of the present disclosure is illustrated.

[0221] Reference Figure 14 ,and Figure 13 In contrast, the transmission and reception operations of feedback frames and response frames within the SLS process can be performed in a different operating frequency band (i.e., the sub-7 GHz frequency band). That is, SLS initiation, transmission and reception of feedback frames, and transmission and reception of response frames can be performed in the sub-7 GHz frequency band, and in the mmWave frequency band, it can be configured / defined as simply transmitting and receiving PPDU / frames for sector scanning.

[0222] First, SLS initiation may be performed in a frequency band below 7 GHz for an AP and a STA ( S1410 ).

[0223] For example, regarding the transmission of the sector scanning and feedback / ACK frames in the SLS process, allocation information of specific time and / or frequency resources (e.g., channels, subchannels) for burst transmission of PPDU / frames by the AP, information on the number of PPDU / frames in the burst, etc. may be indicated. Here, the PPDU / frame may correspond to a packet related to the sector scanning (e.g., an SSW packet).

[0224] In this regard, the specific time and / or frequency resources can be resources allocated for operations in the mmWave band.

[0225] The AP can send a burst of specific PPDUs / frames (S1420) in the allocated time and / or frequency resources.

[0226] In this regard, each PPDU / frame included in the burst can include information indicating the sector ID of the transmission direction. If information about the sector ID and sequence information is sent / indicated in a sub-7 GHz band, this information can be omitted from each PPDU / frame.

[0227] At this time, the STA can measure the best TX sector ID of the AP using the PPDUs / frames included in the burst and perform its own RX sector scan (S1430). In this case, the STA can perform the receive operation in the quasi-omnidirectional mode only during the AP's TX sector scan.

[0228] In this regard, a specific training field (TRN field) for supporting the STA's RX sector scan can be defined to be included at the end of the corresponding PPDU / frame. For example, the specific training field can be designed to have the same or a similar structure as the TRN fields of EDMG BRP-RX / TX PPDUs, TRN-R units, etc.

[0229] Specifically, the STA can perform the receive operation in the quasi-omnidirectional mode only during the AP's TX sector scan and can be configured / defined to operate in the RX sector scan mode only for the specific training field.

[0230] After the AP's burst transmission, the STA can send a feedback frame to the AP in a sub-7 GHz band (S1440).

[0231] Here, the feedback frame can include information about the best TX sector ID of the AP.

[0232] Next, the AP can send a response frame (e.g., an ACK frame) in a sub-7 GHz band (S1450).

[0233] In the simplified process as Figure 14 The STA can use its measured best RX sector in the TX sector direction, and the AP can use its best TX sector fed back from the STA in the RX sector direction.

[0234] That is, regarding the foregoing Figure 14In the steps, steps S1410, S1440, and S1450 can be configured / defined to be executed in a sub-7 GHz band, and steps S1420 and S1430 can be executed in a mmWave band.

[0235] In addition, during a simplification process such as Figure 14 when sending a frame for feedback of information such as the best sector ID in a sub-7 GHz band, competition may be required, which may cause delay.

[0236] Embodiment 2

[0237] This embodiment relates to a method for performing a beam refinement protocol (BRP) process in a wireless LAN system supporting a mmWave band.

[0238] The BRP process may correspond to a sector scanning process to obtain a more refined beamforming pattern after the SLS process in Embodiment 1.

[0239] At this time, to simplify the BRP process, the AP and / or STA may determine some TX sector candidates and RX sector candidates through the SLS process. Information about each sector candidate determined in this way may be indicated in a sub-7 GHz band.

[0240] In addition, the BRP process between the AP and the STA may be performed by allocating specific time and / or frequency resources in a sub-7 GHz band. In this case, some sector candidates may be used to simultaneously perform the TX sector scanning of the AP and the RX sector scanning of the STA. To this end, a specific training field may be inserted into the PPDU / frame sent for sector scanning. For example, the specific training field may be designed to have the same or a similar structure as the TRN field, the TRN-R unit, etc. of the EDMG BRP-RX / TX PPDU.

[0241] In addition, a simplified BRP process may be defined, which does not require a reverse process by utilizing antenna pattern reciprocity.

[0242] To simplify the process, the BRP process in the present disclosure may not include a multi-sector ID detection (MID) process. This is because the RX sector scanning has already been performed in the SLS process, and thus, the MID process corresponding to the process for RX sector scanning is unnecessary.

[0243] Hereinafter, the above BRP process in this embodiment will be specifically described with reference to Figures 15 to 17 Specifically describe the above BRP process in this embodiment.

[0244] Figure 15 An example of the BRP process between the AP and the STA according to an embodiment of the present disclosure is illustrated.

[0245] Refer to Figure 15 For the BRP process between an AP and a STA, the BRP initiation can be configured / defined to be performed in a sub-7 GHz band, and the remaining operations can be performed in a mmWave band.

[0246] First, the BRP initiation (S1510) can be performed for the AP and the STA in the sub-7 GHz band.

[0247] For example, regarding the sector scan and the transmission of feedback / ACK frames in the BRP process, the allocation information for specific time and / or frequency resources (e.g., channels, sub-channels), the information for candidate sectors, and the information for the TX sector pattern order can be indicated.

[0248] In this regard, the specific time and / or frequency resources can be resources allocated for operations in the mmWave band.

[0249] The AP can transmit a specific PPDU / frame (S1520) in the allocated time and / or frequency resources. Here, a specific training field or the like can be inserted into the specific PPDU / frame so that the RX sector scan of the STA can be performed simultaneously with the TX sector scan of the AP. For example, the specific training field can be designed to have the same or a similar structure as the TRN field, the TRN-R unit, etc. of the EDMG BRP-RX / TX PPDU. In this regard, the information on the TX sector pattern of the specific training field or the like can be indicated.

[0250] At this time, the STA can measure the best TX sector ID of the AP using the corresponding PPDU / frame and perform its own RX sector scan (S1530).

[0251] Here, the best TX sector ID can be configured in the form of a list including one or more TX sector IDs.

[0252] After the AP transmits the PPDU / frame, the STA can transmit a specific PPDU / frame (S1540) on the allocated time and / or frequency resources or at a certain time (e.g., SIFS) after the end of the PPDU / frame transmission of the AP on the same frequency resource. Here, a specific training field or the like can be inserted into the specific PPDU / frame so that the RX sector scan of the AP can be performed simultaneously with the TX sector scan of the STA. For example, the specific training field can be designed to have the same or a similar structure as the TRN field, the TRN-R unit, etc. of the EDMG BRP-RX / TX PPDU. In this regard, the information on the TX sector pattern of the specific training field or the like can be indicated. In addition, the STA can feedback the information on the best TX sector ID of the AP to the AP.

[0253] At this time, the AP can use the corresponding PPDU / frame to measure the best TX sector ID of the STA and perform its own RX sector scan (S1550).

[0254] After the STA transmits the PPDU / frame, the AP can send a feedback frame to the STA on the allocated time and / or frequency resources or at a certain time (e.g., SIFS) after the end of the STA's PPDU / frame transmission on the same frequency resource in the direction of the best TX sector feedback by the STA (S1560). Here, the feedback frame can include information about the best TX sector ID of the STA. For example, the STA can receive the feedback frame according to its best RX sector direction.

[0255] After the AP sends the feedback frame, the STA can send a response frame (e.g., ACK frame) on the allocated time and / or frequency resources or at a certain time period (e.g., SIFS) after the end of the AP's feedback frame transmission on the same frequency resource in the direction of the best TX sector feedback by the AP (S1570). For example, the STA can receive the response frame according to its best RX sector direction.

[0256] Regarding the foregoing Figure 15 For the steps described above, step S1510 can be set / defined to be executed in the sub-7GHz band, and the remaining steps (i.e., steps S1520 to S1570) can be set / defined to be executed in the mmWave band.

[0257] Figure 16 Another example of the BRP process between the AP and the STA according to an embodiment of the present disclosure is illustrated.

[0258] Referring to Figure 16 and Figure 15 compared with

[0259] First, the BRP initiation can be performed for the AP and the STA in the sub-7GHz band (S1610).

[0260] For example, regarding the sector scan and the transmission of the feedback / ACK frame in the BRP process, the allocation information for specific time and / or frequency resources (e.g., channel, sub-channel), the information for candidate sectors, and the information for the TX sector pattern order can be indicated.

[0261] In this regard, the specific time and / or frequency resources can be the resources allocated for operations in the mmWave band.

[0262] The AP may transmit a specific PPDU / frame in the allocated time and / or frequency resources (S1620). Here, a specific training field or the like may be inserted into the specific PPDU / frame so that the RX sector scan of the STA can be performed simultaneously with the TX sector scan of the AP. For example, the specific training field may be designed to have the same or a similar structure as the TRN field, the TRN-R unit, etc. of the EDMG BRP-RX / TX PPDU. In this regard, information indicating the TX sector pattern of the specific training field or the like may be provided.

[0263] At this time, the STA may measure the best TX sector ID of the AP using the corresponding PPDU / frame and perform its own RX sector scan (S1630).

[0264] After the AP transmits the PPDU / frame, the STA may use its best RX sector in the same TX direction to transmit a feedback frame to the AP in the allocated time and / or frequency resources or after a certain time amount (e.g., SIFS) after the end of the AP's PPDU / frame transmission in the same frequency resource (S1640). Here, the feedback frame may include information about the best TX sector ID of the AP. For example, the AP may receive the feedback frame in an omni-directional mode. Alternatively, the AP may receive the feedback frame in the best RX direction identified through the above SLS process.

[0265] After the STA transmits the feedback frame, the AP may transmit a response frame (e.g., an ACK frame) on the allocated time and / or frequency resources or after a certain time (e.g., SIFS) after the end of the STA's transmission of the feedback frame on the same frequency resource according to the best TX sector direction feedback by the STA (S1650). In this case, the STA may receive the response frame according to its best RX sector direction.

[0266] In the simplified process as Figure 16 described above, the STA may use its measured best RX sector in the TX sector direction, and the AP may use its best TX sector feedback from the STA in the RX sector direction.

[0267] Regarding the foregoing Figure 16 steps, step S1610 may be configured / defined to be performed in a sub-7 GHz band, and the remaining steps (i.e., steps S1620 to S1650) may be configured / defined to be performed in a mmWave band.

[0268] Figure 17 Another example of the BRP process between the AP and the STA according to an embodiment of the present disclosure is illustrated.

[0269] Referring to Figure 17 , and Figure 16In contrast, the sending and receiving operations of feedback frames and response frames within the BRP process can be performed in different operating frequency bands (i.e., below 7 GHz). That is, BRP initiation, the sending and receiving of feedback frames, and the sending and receiving of response frames can be performed in the sub-7 GHz band, and in the mmWave band, it can be configured / defined to simply send and receive PPDUs / frames for sector scanning.

[0270] First, BRP initiation (S1710) can be performed for the AP and STA in the sub-7 GHz band.

[0271] For example, regarding sector scanning on the BRP process and the sending of feedback / ACK frames, information on the allocation of specific time and / or frequency resources (e.g., channels, sub-channels) for the sending of specific PPDUs / frames for the AP, information on candidate sectors for the AP and STA, and information on the TX sector pattern order within the PPDU / frame for the AP can be indicated.

[0272] In this regard, the specific time and / or frequency resources can be resources allocated for operations in the mmWave band.

[0273] The AP can send a specific PPDU / frame (S1720) in the allocated time and / or frequency resources. Here, a specific training field, etc., can be inserted into the specific PPDU / frame so that the RX sector scanning of the STA can be performed simultaneously with the TX sector scanning of the AP. For example, the specific training field can be designed to have the same or similar structure as the TRN field, TRN-R unit, etc., of the EDMG BRP-RX / TX PPDU. In this regard, information on the TX sector pattern of the specific training field, etc., can be indicated.

[0274] At this time, the STA can use the corresponding PPDU / frame to measure the best TX sector ID of the AP and perform its own RX sector scanning (S1730).

[0275] After the AP sends the PPDU / frame, the STA can send a feedback frame to the AP in the sub-7 GHz band (S1740). Here, the feedback frame can include information on the best TX sector ID of the AP.

[0276] After the STA sends the feedback frame, the AP can send a response frame (e.g., ACK frame) in the sub-7 GHz band (S1750).

[0277] In the simplified process as Figure 17 described, the STA can use its measured best RX sector in the TX sector direction, and the AP can use its best TX sector fed back from the STA in the RX sector direction.

[0278] That is to say, regarding the foregoing Figure 17 steps, steps S1710, S1740, and S1750 can be configured / defined to be executed in a sub-7 GHz band, and steps S1720 and S1730 can be executed in a mmWave band.

[0279] In addition, during a simplification process such as Figure 17 when sending a frame for feedback of information such as the best sector ID in a sub-7 GHz band, contention may be required, which may cause delays.

[0280] Hereinafter, the operation of the STA according to the embodiments of the present disclosure will be described with reference to Figure 18 and Figure 19 That is, Figure 18 and Figure 19 the examples of can correspond to some of the various examples of the present disclosure.

[0281] Figure 18 illustrates an operation flowchart of a first STA according to an embodiment of the present disclosure.

[0282] Referring to Figure 18 regarding the SLS process and the BRP process described in the present disclosure, the first STA can correspond to the responder (e.g., the STA in Figures 12 to 17 ), and the second STA can correspond to the initiator (e.g., the AP in Figures 12 to 17 ).

[0283] In a first operating band, the first STA can identify / be indicated / obtain information related to initiating a sector scan operation (e.g., the SLS process) in a second operating band (S1810).

[0284] In this regard, the first operating band can correspond to one of the 2.4 GHz band, the 5 GHz band, or the 6 GHz band (i.e., the sub-7 GHz band), and the second operating band can correspond to one of the millimeter wave (mmWave) band or the 60 GHz band.

[0285] Here, the information can include allocation information of resources for the sector scan operation.

[0286] For example, the allocated resources can include one or more of time resources or frequency resources allocated for the sector scan operation in the second operating band.

[0287] In a second operating frequency band, when a first STA receives, from a second STA, a plurality of frames for a sector scan operation in the allocated resources, the first STA may measure the best transmission sector (best TX sector) of the second STA and perform its own receive sector scan (RX sector scan) (S1820).

[0288] In this regard, the best transmission sector may be replaced and applied with terms such as the best transmission area, the best transmission direction, the best antenna setting, and the best antenna weight vector.

[0289] For example, the best transmission sector may be selected / determined based on the measured SNR for frame reception, etc. Additionally, the receive sector scan may mean a process in which a STA scans receive beams and selects / determines its best receive sector.

[0290] In this regard, a plurality of frames may be sent in a burst form, and a plurality of frames may be sent based on a TX sector scan. At this time, each frame included in the plurality of frames may include identification information (e.g., ID) of the transmission sector for the frame. Additionally or alternatively, the information related to initiating the sector scan operation may further include information about the number of frames included in the burst to be sent.

[0291] Additionally, each frame included in the plurality of frames may include a training field related to the RX sector scan of the first STA. At this time, for the reception of each frame included in the plurality of frames, the first STA may be configured to receive the training field in a mode based on the RX sector scan and receive the portion of the frame other than the training field in an almost omni - directional mode.

[0292] In a first operating frequency band, a feedback frame including identification information of the best transmission sector of the second STA may be sent to the second STA (S1830).

[0293] In a first operating frequency band, the first STA may receive a response frame to the feedback frame from the second STA (S1840).

[0294] After the above - mentioned sector scan operation (e.g., SLS process), a beam refinement operation (e.g., BRP process) may be additionally performed for more detailed beamforming training.

[0295] For example, in a first operating frequency band, the first STA may identify / be indicated / obtain information related to initiating a beam refinement operation in a second operating frequency band. Here, the information related to initiating the beam refinement operation may include allocation information of resources for the beam refinement operation and identification information of one or more candidate sectors determined based on the foregoing sector scan operation.

[0296] Additionally, in the second operating band, when the first STA receives a specific frame sent from the second STA through TX sector scanning based on one or more candidate sectors in the resources for beam refinement operation, the first STA can measure the best transmission sector of the second STA and perform RX sector scanning of the second STA related to the beam refinement operation.

[0297] Here, the specific frame may include a training field for RX sector scanning associated with the beam refinement operation. In this regard, the information associated with initiating the aforementioned beam refinement operation may also include information regarding the TX sector pattern order within the specific frame.

[0298] Additionally, in the first operating band, the first STA can send a feedback frame including identification information of the best transmission sector of the second STA measured regarding the beam refinement operation to the second STA. Thereafter, in the first operating band, the first STA can receive a response frame from the second STA in response to the feedback frame.

[0299] In Figure 18 the example described by the method performed by the first STA can be performed by Figure 1 the first device (100). For example, Figure 1 one or more processors (102) of the first device (100) can be configured to: identify information related to initiating sector scanning operation in the second operating band through one or more transceivers (106); receive multiple frames based on TX sector scanning; perform the best transmission sector measurement of the second STA and RX sector scanning of the first STA; send a feedback frame; and receive a response frame. In addition, one or more memories (104) of the first device (100) can store commands for performing the Figure 18 example described or the method described in the examples below when executed by one or more processors (102).

[0300] Figure 19 Illustrates an operation flowchart of the second STA according to an embodiment of the present disclosure.

[0301] Referring to Figure 19 , regarding the SLS process and BRP process described in the present disclosure, the first STA can correspond to the responder (e.g., Figures 12 to 17 the STA in Figures 12 to 17 ), and the second STA can correspond to the initiator (e.g.,

[0302] In the first operating band, the second STA can identify / be indicated / obtain information related to initiating sector scanning operation (e.g., SLS process) in the second operating band (S1910). Here, the information may include allocation information of resources for the sector scanning operation.

[0303] In the second operating frequency band, the second STA may send, to the first STA, a plurality of frames for sector scanning operations in the allocated resources (S1920). In this regard, the plurality of frames may be sent in a burst format, and the plurality of frames may be sent based on transmit sector scanning (TX sector scanning).

[0304] In the first operating frequency band, the second STA may receive, from the first STA, a feedback frame including identification information of the best transmit sector of the second STA (S1930). Thereafter, in the first operating frequency band, the second STA may send, to the first STA, a response frame for the feedback frame (S1940).

[0305] In Figure 19 the example of Figure 18 the specific details of the operating frequency band, the sending and receiving of the plurality of frames, the beam refinement operation, the best transmit sector, the receive sector scanning, etc. are the same as those described in the example of

[0306] In Figure 19 the example of Figure 1 the method performed by the second STA described in Figure 1 may be performed by the second device (200) of Figure 19 For example, one or more processors (202) of the second device (200) of

[0307] In an existing wireless LAN system, the content regarding the beamforming training process in the frequency band below 7 GHz is defined. However, the specific content regarding the SLS process and the BRP process for beamforming training in the mmWave frequency band has not been defined. In this regard, the method proposed in the present disclosure is a specific method for performing beamforming training in the mmWave frequency band in consideration of the mmWave frequency band support in the wireless LAN system. Specifically, when performing the SLS process and the BRP process related to beamforming training, it has a new feature that efficient beamforming training can be performed by changing the operating frequency band at each step. According to the method proposed in the present disclosure, a new effect that can improve the throughput and / or efficiency in a newly defined operating frequency band (such as the mmWave frequency band, etc.) can be achieved.

[0308] The above-described embodiments combine the elements and features of the present disclosure in a predetermined form. Unless explicitly stated otherwise, each element or feature should be considered optional. Each element or feature can be implemented in a form that does not combine with other elements or features. Additionally, embodiments of the present disclosure can include combinations of some of the elements and / or features. The order of operations described in the embodiments of the present disclosure can be changed. Some elements or features of one embodiment can be included in other embodiments, or can be replaced with corresponding elements or features of other embodiments. Obviously, embodiments can include combinations of claims that do not have an explicit citation relationship in the claims, or can be included as new claims through amendment after the application.

[0309] It will be apparent to those skilled in the relevant art that the present disclosure can be implemented in other specific forms without departing from the essential characteristics of the present disclosure. Therefore, the above detailed description should not be construed restrictively in every aspect, but should be considered illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0310] The scope of the present disclosure includes software or machine-executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations according to the methods of various embodiments in a device or computer, and non-transitory computer-readable media that enable the software or commands, etc. to be stored and executable in the device or computer. Commands that can be used to program a processing system for performing the features described in the present disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in the present disclosure can be implemented by using a computer program product including such a storage medium. The storage medium can include high-speed random access memories, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, but is not limited thereto, and it can include non-volatile memories, such as one or more disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices located remotely from the processor. The memory, or alternatively, the non-volatile memory device in the memory, includes a non-transitory computer-readable storage medium. The features described in the present disclosure can be stored in any kind of machine-readable medium to control the hardware of the processing system, and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from the embodiments of the present disclosure. Such software or firmware can include application code, device drivers, operating systems, and execution environments / containers, but is not limited thereto.

[0311] Industrial Applicability

[0312] The method proposed by the present disclosure is mainly described based on examples applied to IEEE 802.11-based systems, but can be applied to various WLAN or wireless communication systems other than IEEE 802.11-based systems.

Claims

1. A method performed by a first station STA in a wireless LAN system, the method comprising: In a first operating frequency band, identifying information related to initiating a sector scan operation in a second operating frequency band, the information including allocation information of resources for the sector scan operation; In the second operating frequency band, based on receiving a plurality of frames for the sector scan operation from the second STA in the resources, measuring the best transmission TX sector of the second STA and performing a receiving RX sector scan of the first STA; In the first operating frequency band, sending a feedback frame including identification information for the best TX sector to the second STA; And In the first operating frequency band, receiving a response frame to the feedback frame in the first operating frequency band from the second STA.

2. The method according to claim 1, Among them, The first operating frequency band corresponds to one of a 2.4 GHz frequency band, a 5 GHz frequency band, or a 6 GHz frequency band, and wherein the second operating frequency band corresponds to one of a millimeter wave mmWave frequency band or a 60 GHz frequency band.

3. The method according to claim 1, Among them, The resources include at least one of time resources or frequency resources allocated for the sector scan operation in the second operating frequency band.

4. The method according to claim 1, Among them, Sending the plurality of frames in a burst format, and wherein the plurality of frames are sent based on a TX sector scan.

5. The method according to claim 4, Among them, Each frame included in the plurality of frames includes identification information for the transmission sector of the frame.

6. The method according to claim 4, Among them, The information further includes information on the number of frames included in the burst.

7. The method according to claim 1, Among them, Each frame included in the plurality of frames includes a training field associated with the RX sector scan.

8. The method according to claim 7, Among them, For the reception of each frame included in the plurality of frames, the training field is received in a mode based on the RX sector scan, and a part of the frame excluding the training field is received in a quasi-omnidirectional mode.

9. The method according to claim 1, the method further comprising: In the first operating frequency band, identifying information related to initiating a beam refinement operation in a second operating frequency band, the information related to initiating the beam refinement operation including allocation information of resources for the beam refinement operation and identification information for one or more candidate sectors determined based on the sector scan operation; In the second operating frequency band, based on receiving specific frames sent by applying TX sector scan based on one or more candidate sectors in the resources for the beam refinement operation, measuring the best Tx sector of the second STA and performing an RX sector scan related to the beam refinement operation; In the first operating frequency band, sending a feedback frame including identification information for the best Tx sector to the second STA; And In the first operating frequency band, receiving a response frame to the feedback frame in the first operating frequency band.

10. The method according to claim 9, Among them, The information related to the initiation of the beam refinement operation further includes information on the TX sector pattern order within the specific frame.

11. The method according to claim 9, Among them, The specific frame includes a training field for RX sector scanning related to the beam refinement operation.

12. An apparatus for a first station STA in a wireless local area network WLAN system, the apparatus comprising: At least one transceiver; And At least one processor, the at least one processor being connected to the at least one transceiver, Wherein, the at least one processor is configured to: In a first operating band, identify information related to initiating a sector scanning operation in a second operating band, the information including allocation information of resources for the sector scanning operation; In the second operating band, based on receiving multiple frames for the sector scanning operation from the second STA in the resources, measure the best transmit TX sector of the second STA and perform RX sector scanning of the first STA; In the first operating band, send a feedback frame including identification information for the best TX sector to the second STA; and In the first operating band, receive a response frame to the feedback frame from the second STA.

13. A method performed by a second station STA in a wireless LAN system, the method comprising: In a first operating band, identify information related to initiating a sector scanning operation in a second operating band, the information including allocation information of resources for the sector scanning operation; In the second operating band, send multiple frames for the sector scanning operation to a first STA in the resources; In the first operating band, receive a feedback frame including identification information for the best Tx sector of the second STA from the first STA; And In the first operating band, send a response frame to the feedback frame to the first STA.

14. An apparatus for a second station STA in a wireless local area network WLAN system, the apparatus comprising: At least one transceiver; And At least one processor, the at least one processor being connected to the at least one transceiver, Wherein, the at least one processor is configured to: In a first operating band, identify information related to initiating a sector scanning operation in a second operating band, the information including allocation information of resources for the sector scanning operation; In the second operating band, send multiple frames for the sector scanning operation to a first STA in the resources; In the first operating band, receive a feedback frame including identification information for the best TX sector of the second STA from the first STA; and In the first operating band, send a response frame to the feedback frame to the first STA.

15. A processing unit configured to control a station STA in a wireless local area network WLAN system, the processing unit comprising: At least one processor; And At least one computer memory, the at least one computer memory being operatively connected to the at least one processor and storing instructions for performing the method according to any one of claims 1 to 11 when executed by the at least one processor.

16. At least one non-transitory computer-readable medium storing at least one instruction, wherein the at least one instruction, when executed by at least one processor, controls a device in a wireless local area network (WLAN) system to perform the method according to any one of claims 1 to 11.

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