METHOD AND APPARATUS FOR PERFORMING MILLIMETER WAVE BAND-BASED PPDU TRANSMISSION AND RECEIPT IN WIRELESS LAN SYSTEMS - Patent application

Abstract

A method and apparatus for performing numerology selection-based PPDU transmission and reception in a wireless LAN system are disclosed. According to an embodiment of the present disclosure, the method may include: configuring a PPDU in a first operating frequency band; and transmitting the PPDU to a second STA. Here, a first PPDU format for the PPDU may include a first STF, a first LTF, a SIG field, and a data field. The first PPDU format may be defined by applying an up-clocking element based on a second PPDU format defined for a second operating frequency band. The first STF structure may be configured by repeating a second STF structure included in the second PPDU format twice and then applying the up-clocking element. The first LTF structure may be configured by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, followed by repeating a portion of the second LTF structure excluding the GI twice and then applying the up-clocking element.

Description

[Technical Field]

[0001] The present disclosure relates to a method and apparatus for transmitting and receiving millimeter wave (mmWave) band-based PPDUs in a wireless local area network (WLAN) system. [Background technology]

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

[0003] To provide a more improved wireless communication environment, improved technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for increased bandwidth, efficient use of multiple bands, Multiple Input Multiple Output (MIMO) that supports increased spatial streams, and multiple access point (AP) coordination are being researched. In particular, various technologies for supporting traffic with low latency or real-time characteristics are being researched. Furthermore, new technologies for supporting ultra high reliability (UHR), including improvements or extensions to EHT technology, are being discussed. Summary of the Invention [Problem to be solved by the invention]

[0004] The technical problem of the present disclosure is to provide a method and apparatus for transmitting and receiving millimeter wave (mmWave) band-based PPDUs in a wireless local area network (WLAN) system.

[0005] The technical problem of the present disclosure is to provide a method and apparatus for defining a PPDU format in a millimeter wave band based on a predefined numerology and upclocking application, and for transmitting and receiving PPDUs in the millimeter wave band based on the PPDU format.

[0006] The technical problems to be solved by the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Means for solving the problem]

[0007] A method performed by a first station (STA) in a wireless LAN system according to one embodiment of the present disclosure may include configuring a physical layer protocol data unit (PPDU) in a first operating frequency band and transmitting the PPDU to a second STA, wherein a first PPDU format for the PPDU includes a first short training field (STF), a first long training field (LTF), a signal (SIG) field, and a data field, the first PPDU format is defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band, the first STF structure may be configured by repeating a second STF structure included in the second PPDU format twice and then applying the upclocking factor, and the first LTF structure may be configured by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, followed by repeating a portion of the second LTF structure excluding the GI twice and then applying the upclocking factor.

[0008] A method performed by a second station (STA) in a wireless LAN system according to a further aspect of the present disclosure may include receiving a physical layer protocol data unit (PPDU) from a first STA in a first operating frequency band, and processing the PPDU, wherein a first PPDU format for the PPDU includes a first short training field (STF), a first long training field (LTF), a signal (SIG) field, and a data field, the first PPDU format being defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band, the first STF structure being configured by repeating a second STF structure included in the second PPDU format twice and then applying the upclocking factor, and the first LTF structure being configured by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, followed by repeating a portion of the second LTF structure excluding the GI twice and then applying the upclocking factor. [Effects of the Invention]

[0009] According to the present disclosure, a method and apparatus for transmitting and receiving millimeter wave (mmWave) band-based PPDUs in a wireless local area network (WLAN) system can be provided.

[0010] According to the present disclosure, a method and apparatus can be provided for defining a PPDU format in a millimeter wave band based on a predefined numerology and upclocking application, and for transmitting and receiving a PPDU in the millimeter wave band based on this.

[0011] According to the present disclosure, it is possible to support the mmWave band in a wireless LAN system and achieve high data rates and low latency.

[0012] The effects obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief explanation of the drawings]

[0013] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present disclosure, provide examples for the present disclosure and, together with the detailed description, explain the technical features of the present disclosure. [Figure 1] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied. [Figure 3] FIG. 1 is a diagram illustrating a link setup process to which the present disclosure can be applied. [Figure 4] FIG. 10 is a diagram illustrating a backoff process to which the present disclosure can be applied. [Figure 5] 10A and 10B are diagrams for explaining a CSMA / CA base frame transmission operation to which the present disclosure can be applied. [Figure 6] 1 is a diagram illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied. [Figure 7] FIG. 1 illustrates an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure is applicable. [Figure 8] FIG. 1 is a diagram illustrating an example of a resource unit in a wireless LAN system to which the present disclosure can be applied. [Figure 9] FIG. 1 is a diagram illustrating an example of a resource unit in a wireless LAN system to which the present disclosure can be applied. [Figure 10]FIG. 1 is a diagram illustrating an example of a resource unit in a wireless LAN system to which the present disclosure can be applied. [Figure 11] FIG. 1 illustrates an example of the channelization of millimeter wave (mmWave) bands by region to which the present disclosure can be applied. [Figure 12] FIG. 1 is a diagram illustrating an example of a PPDU format in the mmWave band according to an embodiment of the present disclosure. [Figure 13] FIG. 10 is a diagram illustrating another example of a PPDU format in the mmWave band according to an embodiment of the present disclosure. [Figure 14] FIG. 10 is a diagram illustrating yet another example of a PPDU format in the mmWave band according to an embodiment of the present disclosure. [Figure 15] FIG. 10 is a diagram illustrating the operation of a first STA according to an embodiment of the present disclosure. [Figure 16] FIG. 10 is a diagram illustrating the operation of a second STA according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure can be implemented. The detailed description below includes specific details to provide a complete understanding of the present disclosure. However, it will be understood by those skilled in the art that the present disclosure can be implemented without such specific details.

[0015] In some cases, in order to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or shown in block diagram form, focusing on the core functions of each structure and device.

[0016] In the present disclosure, when a component is "coupled," "coupled," or "connected" to another component, this may include a direct connection as well as an indirect connection where there is another component between them. Also, in the present disclosure, the terms "comprise" or "have" (comprise; constitute; construct; set; encompass; include; contain) specify the presence of stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0017] In this disclosure, terms such as "first" and "second" are used only to distinguish one component from another, and are not used to limit the components, and do not limit the order or importance of the components unless otherwise specified. Therefore, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0018] The terms used in this disclosure are for the purpose of describing particular embodiments and are not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular is intended to include the plural unless the context clearly dictates otherwise. The term "and / or" as used in this disclosure means that one of the associated listed items may be included, or that any and all possible combinations of two or more of them are included. Also, in this disclosure, " / " between words has the same meaning as "and / or" unless otherwise specified.

[0019] The examples of the present disclosure may be applied to various wireless communication systems. For example, the examples of the present disclosure may be applied to a wireless LAN system. For example, the examples of the present disclosure may be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax / be standard. Note that the examples of the present disclosure may also be applied to a newly proposed IEEE 802.11bn (or UHR) standard-based wireless LAN. Furthermore, the examples of the present disclosure may also be applied to a next-generation standard-based wireless LAN after IEEE 802.11bn. Furthermore, the examples of the present disclosure may also be applied to a cellular wireless communication system. For example, the examples of the present disclosure may be applied to a cellular wireless communication system based on the Long Term Evolution (LTE) series of technologies and the 5G New Radio (NR) series of technologies of the 3GPP (3rd Generation Partnership Project: registered trademark) standard.

[0020] Below, technical features to which the examples of the present disclosure can be applied will be described.

[0021] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure.

[0022] 1 may be referred to by 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 (MSS), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user. In addition, the first device 100 and the second device 200 may be referred to by various terms such as an access point (AP), a base station (BS), a fixed station, a Node B, a base transceiver system (BTS), a network, an artificial intelligence (AI) system, a road side unit (RSU), a repeater, a router, a relay, a gateway, etc.

[0023] The devices 100 and 200 illustrated in FIG. 1 may also be referred to as stations (STAs). For example, the devices 100 and 200 illustrated in FIG. 1 may be referred to by various terms, such as a transmitting device, a receiving device, a transmitting STA, or a receiving STA. For example, the STAs 110 and 200 may serve as an access point (AP) or a non-AP. That is, in the present disclosure, the STAs 110 and 200 may have AP and / or non-AP functionality. When the STAs 110 and 200 have AP functionality, they may simply be referred to as APs, and when the STAs 110 and 200 have non-AP functionality, they may simply be referred to as STAs. Also, in the present disclosure, an AP may be referred to as an AP STA.

[0024] 1, a first device 100 and a second device 200 may transmit and receive wireless signals using various wireless LAN technologies (e.g., the IEEE 802.11 family). The first device 100 and the second device 200 may include interfaces for a medium access control (MAC) layer and a physical layer (PHY) in accordance with the IEEE 802.11 standard.

[0025] In addition, the first device 100 and the second device 200 may further support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) other than WLAN technology. Furthermore, the devices of the present disclosure may be embodied as various devices such as mobile phones, vehicles, personal computers, augmented reality (AR) equipment, and virtual reality (VR) equipment. Furthermore, the STAs of the present disclosure may support various communication services such as voice calls, video calls, data communications, autonomous driving, machine-type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), and Internet-of-Things (IoT).

[0026] The first device 100 includes one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may be configured to control the memory 104 and / or the transceiver 106 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts of the present disclosure. For example, the processor 102 may process information in the memory 104 to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceiver 106. The processor 102 may also receive a wireless signal including second information / signals via the transceiver 106, and then store information obtained from signal processing of the second information / signals in the memory 104. The memory 104 may be coupled 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 executing some or all of the processes controlled by the processor 102 or for implementing the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts in this disclosure. Here, the processor 102 and the memory 104 may be part of a communications modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be coupled to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with an RF (Radio Frequency) unit. In this disclosure, a device may also refer to a communications modem / circuit / chip.

[0027] The second device 200 includes one or more processors 202, 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 be configured to control the memory 204 and / or the transceiver 206 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure. For example, the processor 202 may process information in the memory 204 to generate third information / signal, and then transmit a wireless signal including the third information / signal via the transceiver 206. The processor 202 may also receive a wireless signal including fourth information / signal via the transceiver 206, and then store information obtained from signal processing of the fourth information / signal in the memory 204. The memory 204 may be coupled to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for executing some or all of the processes controlled by the processor 202 or for implementing the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure. Here, the processor 202 and the memory 204 may be part of a communications modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 206 may be coupled to the processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In this disclosure, a device may also refer to a communications modem / circuit / chip.

[0028] The hardware elements of the devices 100 and 200 are described in more detail below. Without limitation, 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., the same functional layer, such as PHY or MAC). The one or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in this disclosure. The 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 operational flow diagrams in this disclosure. The one or more processors 102, 202 can generate and provide signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods of this disclosure to the one or more transceivers 106, 206. The one or more processors 102, 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts of this disclosure.

[0029] The one or more processors 102, 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. The one or more processors 102, 202 may be implemented using hardware, firmware, software, or a combination thereof. As an example, the one or more processors 102, 202 may include one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs). The descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in this disclosure may be included in one or more processors 102, 202 or stored in one or more memories 104, 204 and executed by one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in this disclosure may be embodied by firmware or software in the form of code, instructions, and / or collections of instructions.

[0030] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and may store various types of data, signals, messages, information, programs, code, instructions, and / or instructions. The one or more memories 104, 204 may be comprised of ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories 104, 204 may be located internal and / or external to the one or more processors 102, 202. Additionally, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 via various techniques, such as wired or wireless connections.

[0031] One or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc., as referred to in the methods and / or operational flowcharts of the present disclosure, to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc., as referred to in the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts of the present disclosure, from one or more other devices. For example, one or more transceivers 106, 206 may be coupled 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. Also, 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. Furthermore, one or more transceivers 106, 206 may be coupled to one or more antennas 108, 208, and may be configured to transmit or receive user data, control information, wireless signals / channels, etc., as referred to in the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure, via the one or more antennas 108, 208. In this disclosure, the one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 may convert the received user data, control information, wireless signals / channels, etc., from RF band signals to baseband signals for processing using one or more processors 102, 202. The one or more transceivers 106, 206 may convert the user data, control information, wireless signals / channels, etc., processed using one or more processors 102, 202, from baseband signals to RF band signals. To that end, one or more of the transceivers 106, 206 may include (analog) oscillators and / or filters.

[0032] For example, one of the STAs 100 and 200 may perform operations intended for an AP, and the other of the STAs 100 and 200 may perform operations intended for a non-AP STA. For example, the transceivers 106 and 206 in FIG. 1 may perform operations for transmitting and receiving signals (e.g., packets or PPDUs (Physical Layer Protocol Data Units) conforming to IEEE 802.11a / b / g / n / ac / ax / be, etc.). In addition, in the present disclosure, operations for various STAs to generate transmission / reception signals or to perform data processing or calculations in advance for transmission / reception signals may be performed by the processors 102 and 202 in FIG. 1. 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) operations for determining / obtaining / configuring / calculating / decoding / encoding bit information of fields included in a PPDU (SIG (signal), STF (short training field), LTF (long training field), Data, etc.); 2) operations for determining / configuring / obtaining time resources and frequency resources (e.g., subcarrier resources) to be used for fields included in a PPDU (SIG, STF, LTF, Data, etc.); 3) operations for determining / configuring / obtaining specific sequences (e.g., pilot sequences, STF / LTF sequences, extra sequences applied to SIG) to be used for fields included in a PPDU (SIG, STF, LTF, Data, etc.); 4) power control operations and / or power saving operations applied to STAs; and 5) operations related to determining / obtaining / configuring / calculating / decoding / encoding ACK signals, etc. In addition, in the following example, various information (e.g., information regarding fields / subfields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmitted and received signals may be stored in memories 104, 204 of FIG. 1.

[0033] Hereinafter, downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. may be transmitted and received via the downlink. In downlink communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. Uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. may be transmitted and received via the uplink. In uplink communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

[0034] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0035] The structure of a WLAN system may be composed of multiple components. The interaction of these components may provide a WLAN that supports STA mobility transparent to higher layers. A Basic Service Set (BSS) is a basic building block of a WLAN. FIG. 2 illustrates two BSSs (BSS1 and BSS2), each including two STAs as members (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). The ellipses representing BSSs in FIG. 2 may be understood to represent coverage areas where STAs included in the BSSs maintain communication. This area may be referred to as a Basic Service Area (BSA). If a STA moves outside a BSA, it will no longer be able to directly communicate with other STAs within the BSA.

[0036] Ignoring the DS shown in FIG. 2, the most basic type of BSS in a WLAN is the Independent BSS (IBSS). For example, an IBSS may have a minimal configuration consisting of only two STAs. For example, assuming that other components are omitted, BSS1 consisting of only STA1 and STA2, or BSS2 consisting of only STA3 and STA4, are representative examples of an IBSS. Such a configuration is possible when STAs can communicate directly without an AP. Furthermore, in such a WLAN, a BSS may be configured when needed by the LAN, rather than being configured in advance. This can also be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs may be mobile, and connection to a distributed system (DS) is not permitted, forming a self-contained network.

[0037] The membership of STAs in a BSS may change dynamically as STAs join and leave the BSS area, etc. To become a member of a BSS, a STA may join the BSS using a synchronization process. To access all the services of the BSS-based architecture, a STA must be associated with the BSS. Such association may be dynamically configured and may include the use of a Distribution System Service (DSS).

[0038] In a wireless LAN, direct STA-to-STA distance may be limited by PHY performance. While such distance limits are sufficient in some cases, other situations may require communication between STAs over longer distances. To support extended coverage, a distributed system (DS) may be configured.

[0039] A DS refers to a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component of an expanded network composed of multiple BSSs. A DS is a logical concept and may be specified by the characteristics of a distributed system medium (DSM). In this regard, a wireless medium (WM) and a DSM may be logically distinguished. Each logical medium is used for different purposes and by different components. These media are neither limited to being the same nor limited to being different. The flexibility of a WLAN structure (DS structure or other network structure) can be explained by the fact that multiple media are logically distinct from one another. That is, a WLAN structure may be embodied in various ways, and the WLAN structure may be independently specified according to the physical characteristics of each implementation.

[0040] The DS can support mobile devices by providing seamless integration of multiple BSSs and logical services necessary for addressing destinations. The DS may also include a portal component that acts as a bridge between the wireless LAN and other networks (e.g., IEEE 802.X).

[0041] An AP is an entity that allows associated non-AP STAs to access the DS through the WM and also has the functionality of an STA. Data can be transferred between a BSS and a DS via the AP. For example, STA2 and STA3 shown in FIG. 2 have the functionality of an STA and provide the function of allowing associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs essentially correspond to STAs, all APs are addressable entities. The address used by an AP for communication on the WM does not necessarily have to be the same as the address used by the AP for communication on the DSM. A BSS consisting of an AP and one or more STAs can be called an infrastructure BSS.

[0042] Data transmitted from any one of the STAs coupled to the AP to the STA address of the AP is always received on the uncontrolled port and may be processed by the IEEE 802.1X port access entity, and once the controlled port is authenticated, the transmitted data (or frame) may be delivered to the DS.

[0043] In the above-described DS structure, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0044] An ESS is a network of arbitrary size and complexity composed of a DS and a BSS. An ESS can be a collection of BSSs connected to one DS. However, an ESS does not include a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in one ESS may have the same service set identification (SSID). An SSID is distinct from a BSSID, which is an identifier for a BSS.

[0045] A WLAN system does not make any assumptions about the relative physical locations of BSSs and can have any of the following configurations: BSSs may partially overlap, which is a configuration commonly used to provide continuous coverage; BSSs may not be physically connected, and there is no logical limit to the distance between BSSs; BSSs may be physically located in the same location, which may be used to provide redundancy; and one (or more) IBSS or ESS networks may physically exist in the same space as one (or more) ESS networks. This may apply to ESS network configurations when an ad-hoc network operates in the location where the ESS network exists, when physically overlapping wireless networks are formed by different organizations, or when two or more different access and security policies are required in the same location.

[0046] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0047] In order for an STA to set up a link to a network and transmit and receive data, it must first discover the network, perform authentication, establish an association, and perform authentication procedures for security. The link setup process can also be called a session initiation process or a session setup process. In addition, the discovery, authentication, association, and security configuration processes of the link setup process can also be collectively called the association process.

[0048] In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access a network, the STA must search for a joinable network. Before joining a wireless network, the STA must identify a compatible network. The process of identifying networks present in a specific area is called scanning.

[0049] Scanning methods include active scanning and passive scanning. FIG. 3 illustrates an example of a network discovery operation including an active scanning process. In active scanning, a scanning STA changes channels and transmits a probe request frame to search for nearby APs, and waits for a response. A responder transmits a probe response frame to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In a BSS, the AP transmits beacon frames, so the AP is the responder. In an IBSS, the STAs in the IBSS transmit beacon frames alternately, so the responder is not constant. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information contained in the received probe response frame, move to the next channel (e.g., channel 2), and perform scanning in the same manner (i.e., send and receive probe requests / responses on channel 2).

[0050] Although not shown in FIG. 3, the scanning operation may be performed in a passive scanning manner. In passive scanning, a scanning STA waits for a beacon frame while changing channels. A beacon frame is a management frame defined in IEEE 802.11 and is periodically transmitted to announce the existence of a wireless network and allow a scanning STA to search for and join the wireless network. In a BSS, the AP is responsible for periodically transmitting beacon frames, while in an IBSS, STAs within the IBSS transmit beacon frames in turn. When a scanning STA receives a beacon frame, it saves the BSS-related information included in the beacon frame and records the beacon frame information on each channel as it moves to other channels. A STA that receives a beacon frame saves the BSS-related information included in the received beacon frame, moves to the next channel, and scans the next channel in the same manner. Comparing active scanning with passive scanning, active scanning has the advantage of having a smaller delay and power consumption than passive scanning.

[0051] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be called a first authentication process to clearly distinguish it from the security setup operation in step S340, which will be described later.

[0052] The authentication process involves a STA sending an authentication request frame to an AP, and the AP responding by sending an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0053] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), a Finite Cyclic Group, etc. These are only examples of information that may be included in an authentication request / response frame, and other information may be substituted or additional information may be included.

[0054] The STA can send an authentication request frame to the AP. The AP can determine whether to allow authentication for the STA based on the information contained in the received authentication request frame. The AP can provide the STA with the result of the authentication process using an authentication response frame.

[0055] After the STA is successfully authenticated, an association process may be performed in step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA.

[0056] For example, the association request frame may include information on various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information on various capabilities, a status code, an association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. This corresponds to only a partial example of information that may be included in the association request / response frame, and other information may be substituted or additional information may be included.

[0057] After the STA is successfully connected to the network, a security setup process may be performed in step S340. The security setup process in step S340 may also be referred to as an authentication process using a Robust Security Network Association (RSNA) request / response, and the authentication process in step S320 may be referred to as a first authentication process, and the security setup process in step S340 may simply be referred to as an authentication process.

[0058] The security setup process of step S340 may include a process of performing private key setup using, for example, four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame, and may also be performed using a security method not defined in the IEEE 802.11 standard.

[0059] FIG. 4 is a diagram illustrating a backoff process to which the present disclosure can be applied.

[0060] In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism, also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, which basically employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA can perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time period (e.g., a DCF Inter-Frame Space (DIFS)) before starting transmission. If the sensing result indicates that the medium is in an idle status, the AP and / or STA can start transmitting a frame over the medium. On the other hand, if the medium is detected as occupied or busy, the AP and / or STA can wait for a delay period (e.g., a random backoff period) for medium access without starting its own transmission, and then attempt to transmit a frame. By applying the random backoff period, multiple STAs are expected to wait for different periods of time before attempting to transmit a frame, thereby minimizing collisions.

[0061] The IEEE 802.11 MAC protocol also provides a Hybrid Coordination Function (HCF). HCF is based on the DCF and Point Coordination Function (PCF). PCF is a polling-based synchronous access method that periodically polls all receiving APs and / or STAs to receive data frames. HCF also includes Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). EDCA is a contention-based access method for a provider to provide data frames to multiple users, while HCCA is a non-contention-based channel access method using a polling mechanism. HCF also includes a medium access mechanism for improving the quality of service (QoS) of wireless LANs and can transmit QoS data in both the contention period (CP) and the contention-free period (CFP).

[0062] The operation based on the random backoff period will be described with reference to FIG. 4. When an occupied / busy medium changes to an idle state, multiple STAs can attempt to transmit data (or frames). As a method for minimizing collisions, each STA can 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 may be determined to be one of the values ​​in the range of 0 to CW. Here, CW is the contention window parameter value. The CW parameter is given a CWmin as its initial value, but can be doubled in the event of a transmission failure (e.g., if an ACK for a transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and if data transmission is successful, it is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are set to 2. n Preferably it is set to -1 (n=0,1,2,...).

[0063] When the random backoff process begins, the STA continuously monitors the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the STA stops counting down and waits. If the medium becomes idle, the STA resumes the remaining countdown.

[0064] In the example of FIG. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 confirms that the medium is idle for DIFS and can immediately transmit a frame. The remaining STAs monitor the medium for occupied / busy status and wait. Meanwhile, STA1, STA2, and STA5 may each have data to transmit. If each STA monitors the medium as idle, it waits for DIFS and then counts down its backoff slots according to its random backoff count value. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. That is, this example illustrates a case where, at the time STA2 finishes its backoff count and begins frame transmission, STA5's remaining backoff time is shorter than STA1's remaining backoff time. STA1 and STA5 pause their countdowns and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume their backoff counts. That is, STA5 can start frame transmission after counting down the remaining backoff slots equal to the remaining backoff time. Because STA5's remaining backoff time is shorter than STA1's, STA5 begins frame transmission. While STA2 is occupying the medium, STA4 may also have data to transmit. From STA4's perspective, when the medium becomes idle, it waits for DIFS, then counts down the random backoff count value it selected, and can begin frame transmission. The example in FIG. 4 shows a case where STA5's remaining backoff time happens to match STA4's random backoff count value, which may result in a collision between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 will receive an ACK, resulting in a failed data transmission. In this case, STA4 and STA5 can double their CW values, select a random backoff count value, and then count down.STA1 waits while the medium is occupied by transmissions from STA4 and STA5, but when the medium becomes idle, it waits for DIFS and can begin frame transmission once the remaining backoff time has elapsed.

[0065] As shown in the example of Figure 4, a data frame is a frame used for transmitting data to be forwarded to a higher layer, and may be transmitted after a backoff that occurs after a DIFS has elapsed since the medium became idle. Furthermore, a management frame is a frame used for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff that occurs after an IFS, such as a DIFS or a PIFS (Point Coordination Function IFS). Subtype frames of management frames include a beacon, an association request / response, a re-association request / response, a probe request / response, and an authentication request / response. A control frame is a frame used to control access to a medium. Subtype frames of control frames include Request-To-Send (RTS), Clear-To-Send (CTS), Acknowledgment (ACK), Power Save-Poll (PS-Poll), BlockAck, BlockACKReq, NDP announcement (null data packet announcement), and Trigger. If a control frame is not a response frame of a previous frame, it is transmitted after a backoff that is performed after a DIFS has elapsed. If a control frame is a response frame of a previous frame, it is transmitted without a backoff after a short IFS (SIFS) has elapsed. The type and subtype of a frame may be identified by the type field and subtype field in the Frame Control (FC) field.

[0066] A Quality of Service (QoS) STA can transmit a frame after backing off after the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), has elapsed. Here, a frame that can use AIFS[i] can be a data frame, a management frame, or a control frame that is not a response frame.

[0067] FIG. 5 is a diagram for explaining a CSMA / CA base frame transmission operation to which the present disclosure can be applied.

[0068] As mentioned above, the CSMA / CA mechanism includes not only physical carrier sensing, in which a STA directly senses the medium, but also virtual carrier sensing. Virtual carrier sensing is intended to compensate for problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of a STA can use a network allocation vector (NAV). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available for use by a STA currently using or authorized to use the medium. Therefore, the value set as the NAV corresponds to the period during which the STA transmitting the frame plans to use the medium, and STAs receiving the NAV value are prohibited from accessing the medium during that period. For example, the NAV may be set based on the value of the "duration" field in the MAC header of the frame.

[0069] In the example of FIG. 5, it is assumed that STA1 is attempting to transmit data to STA2, and STA3 is in a position where it can overhear some or all of the frames transmitted between STA1 and STA2.

[0070] In order to reduce the possibility of collisions between transmissions from multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, STA3 may determine that the medium is idle as a result of carrier sensing. That is, STA1 may be a hidden node to STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, STA3 may determine that the medium is idle as a result of carrier sensing. That is, STA2 may be a hidden node to STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or outside the carrier sensing range for transmissions from STA1 or STA3, can be prevented from attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0071] Specifically, STA1 can determine whether a channel is occupied or not using carrier sensing. In terms of physical carrier sensing, STA1 can determine whether a channel is occupied or idle based on the energy magnitude or signal correlation detected from the channel. In terms of virtual carrier sensing, STA1 can determine whether a channel is occupied or idle using a network allocation vector (NAV) timer.

[0072] When the channel is idle in DIFS, STA1 can send an RTS frame to STA2 after backing off. When STA2 receives the RTS frame, it can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0073] 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 a NAV timer for the frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) that will be transmitted subsequently. Alternatively, if STA3 cannot overhear the RTS frame from STA1 but can overhear the CTS frame from STA2, STA3 can use the duration information included in the CTS frame to set a NAV timer for the frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame) that will be transmitted subsequently. That is, if STA3 can overhear one or more RTS or CTS frames from at least one of STA1 and STA2, it can set a NAV based thereon. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0074] When STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 SIFS after the completion of reception of the CTS frame. When STA2 successfully receives a data frame, it can transmit an ACK frame, which is a response to the data frame, to STA1 SIFS after the completion of reception of the CTS frame. When STA2 successfully receives a data frame, it can transmit an ACK frame, which is a response to the data frame, to STA1 SIFS after the expiration of the NAV timer. When STA3 determines that the channel is not being used by another terminal during the DIFS period after the expiration of the NAV timer, it can attempt channel access after the contention window (CW) with random backoff has elapsed.

[0075] FIG. 6 is a diagram illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0076] The PHY layer can prepare an MPDU (MAC PDU) to be transmitted based on an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when the PHY layer receives a command from the MAC layer requesting the start of PHY layer transmission, the PHY layer switches to transmission mode and transmits information (e.g., data) provided by the MAC layer in the form of a frame. In addition, when the PHY layer detects a valid preamble in a received frame, it monitors the preamble header and sends a command to the MAC layer informing the start of PHY layer reception.

[0077] Thus, information transmission / reception in a wireless LAN system is performed in the form of frames, for which a PHY layer protocol data unit (PPDU) format is defined.

[0078] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., non-High Throughput (HT) shown in FIG. 7) may consist of only a Legacy-STF (L-STF), a Legacy-LTF (L-LTF), a SIG field, and a Data field. Depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, Very High Throughput (VHT) PPDU, etc.), an additional (or other type) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the Data field. More specific details will be described later with reference to FIG. 7.

[0079] The STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, precise time synchronization, etc., and the LTF is a signal for channel estimation, frequency error estimation, etc. The STF and LTF can be said to be signals for synchronization and channel estimation of the OFDM physical layer.

[0080] The SIG field may contain various information related to the transmission and reception of the PPDU. For example, the L-SIG field may be composed of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved field, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The Rate field may contain information regarding the modulation and coding rate of the data. For example, the 12-bit Length field may contain information regarding the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of PPDU. For example, for a non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for an HE PPDU, the value of the Length field may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0081] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used for synchronization of a descrambler at the receiving end. The PSDU corresponds to a MAC PDU defined in the MAC layer and may contain data generated / used by a higher layer. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bits may be used to adjust the length of the data field to a predetermined unit.

[0082] The MAC PDU is defined by various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). The MAC frame is composed of the MAC PDU and may be transmitted / received by the PSDU in the data portion of the PPDU format.

[0083] 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 frame, etc. The Address subfield may indicate the receiver address, transmitter address, destination address, or source address of the frame, and some address subfields may be omitted. For specific contents of each subfield of the MAC header, including the Sequence Control, QoS Control, and HT Control subfields, please refer to the IEEE 802.11 standard document.

[0084] The null data PPDU (NDP) format refers to a PPDU format that does not include a data field, i.e., NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and, if present, non-legacy SIG, non-legacy STF, and non-legacy LTF) in a general PPDU format, but does not include the remaining part (i.e., data field).

[0085] FIG. 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure is applicable.

[0086] Various types of PPDUs are used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes an L-LTF, an L-STF, an L-SIG, and a Data field. The basic PPDU format can also be called a non-HT PPDU format (see FIG. 7(a)).

[0087] The HT PPDU format (IEEE 802.11n) further includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format shown in Figure 7(b) can be referred to as an HT-mixed format. An HT-greenfield format PPDU may also be defined, which corresponds to a format that does not include L-STF, L-LTF, or L-SIG, but is composed of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field (not shown).

[0088] An example of a VHT PPDU format (IEEE 802.11ac) further includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (FIG. 7(c)).

[0089] An example of the HE PPDU format (IEEE 802.11ax) further includes the fields Repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and Packet Extension (PE) in addition to the basic PPDU format (FIG. 7(d)). Depending on the detailed example of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multiple users (MU), but not in the HE PPDU format for single users (SU). Also, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may be changed to microseconds (us). The HE Extended Range (ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may be changed to 16 us. For example, the RL-SIG may be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA can determine whether the received PPDU is an HE PPDU or an EHT PPDU (described later).

[0090] The EHT PPDU format may include the EHT MU (multi-user) PPDU in Figure 7(e) and the EHT TB (trigger-based) PPDU in Figure 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an L-SIG followed by an RL-SIG, but may also include a U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0091] The EHT MU PPDU in Figure 7(e) corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU may be used for both SU transmission and MU transmission. For example, the EHT MU PPDU may correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0092] The EHT TB PPDU in Figure 7(f) omits the EHT-SIG compared to the EHT MU PPDU. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0093] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), and EHT-SIG fields may be encoded and modulated and mapped based on a predetermined subcarrier frequency interval (e.g., 312.5 kHz) so that legacy STAs can also attempt demodulation and decoding. These may be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields may be encoded and modulated and mapped based on a predetermined subcarrier frequency interval (e.g., 78.125 kHz) so that they can be demodulated and decoded by STAs that successfully decode non-legacy SIGs (e.g., U-SIG and / or EHT-SIG) and obtain the information contained in these fields. These may be referred to as EHT modulated fields.

[0094] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as free HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulation fields. Also, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as free VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0095] The U-SIG included in the EHT PPDU format of Fig. 7 may be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4 us, and the entire U-SIG may have a duration of 8 us. Each symbol of the U-SIG may be used to transmit 26 bits of information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0096] U-SIGs may be configured in 20 MHz units. For example, when an 80 MHz PPDU is configured, the same U-SIG may be duplicated in 20 MHz units. That is, four identical U-SIGs may be included in an 80 MHz PPDU. When the bandwidth exceeds 80 MHz, for example, for a 160 MHz PPDU, the first U-SIG in the 80 MHz unit and the second U-SIG in the 80 MHz unit may be different from each other.

[0097] For example, a U-SIG may transmit A uncoded bits, with the first symbol of the U-SIG (e.g., U-SIG-1 symbol) transmitting the first X bits of the total A bits of information, and the second symbol of the U-SIG (e.g., U-SIG-2 symbol) transmitting the remaining Y bits of information of the total A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit field). The tail field may be used to terminate the trellis of a convolutional decoder and may be set to 0, for example.

[0098] The A-bit information transmitted by the U-SIG may be divided into version-independent bits and version-dependent bits. For example, the U-SIG may be included in a new PPDU format (e.g., a UHR PPDU format) not shown in FIG. 7. In the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, but some or all of the version-dependent bits may be different.

[0099] For example, the size of the version-independent bits in a U-SIG may be fixed or variable. The version-independent bits may be assigned only to the U-SIG-1 symbol or to both the U-SIG-1 and U-SIG-2 symbols. The version-independent bits and version-dependent bits may be referred to by various names, such as first control bits and second control bits.

[0100] For example, the version independent bits of the U-SIG may include a 3-bit PHY version identifier, which may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted and received PPDU. The version independent bits of the U-SIG may include a 1-bit UL / DL flag field. A first value of the 1-bit UL / DL flag field is associated with UL communication, and a second value of the UL / DL flag field is associated with DL communication. The version independent bits of the U-SIG may include information regarding the length of a transmission opportunity (TXOP) and information regarding a BSS color ID.

[0101] For example, the version dependent bits of the U-SIG may contain information that directly or indirectly indicates the type of PPDU (eg, SU PPDU, MU PPDU, TB PPDU, etc.).

[0102] Information necessary for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information about the bandwidth, information about the MCS scheme applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether a dual carrier modulation (DCM) scheme (e.g., a scheme for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, information about whether the non-legacy SIG is generated across the entire band, etc.

[0103] Some of the information necessary for PPDU transmission and reception may be included in the U-SIG and / or non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information on the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information on the length of the non-legacy LTF and the cyclic prefix (CP) length, information on the guard interval (GI) applied to the non-legacy LTF, information on preamble puncturing applicable to the PPDU, information on resource unit (RU) allocation, etc. may be included only in the U-SIG, or only in the non-legacy SIG, or may be indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0104] Preamble puncturing may refer to the transmission of a PPDU in which no signal is present in one or more frequency units of the PPDU bandwidth. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to PPDU bandwidths equal to or larger than a predetermined size.

[0105] In the example of Figure 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may contain control information for the receiving STA. The non-legacy SIGs may be transmitted in at least one symbol, and one symbol may have a length of 4us. Information regarding the number of symbols used for the EHT-SIG may be included in previous SIGs (e.g., HE-SIG-A, U-SIG, etc.).

[0106] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include common fields and user-specific fields, which may be coded separately.

[0107] In some cases, the common field may be omitted. For example, in a compressed mode where non-OFDMA (orthogonal frequency multiple access) is applied, the common field may be omitted, and multiple STAs may receive the PPDU (e.g., the data field of the PPDU) in the same frequency band. In an uncompressed mode where OFDMA is applied, multiple users may receive the PPDU (e.g., the data field of the PPDU) in different frequency bands.

[0108] The number of user-specific fields may be determined based on the number of users. One user block field may include up to two user fields. Each user field may be associated with a MU-MIMO allocation or a non-MU-MIMO allocation.

[0109] The common field may include CRC bits and tail bits, where the length of the CRC bits may be determined to be 4 bits, and the length of the tail bits may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the locations of RUs to which multiple users (i.e., multiple receiving STAs) are allocated.

[0110] An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on OFDMA techniques. An RU may also be defined when transmitting a signal to a single STA. Resources may be allocated in RU units for the non-legacy STF, non-legacy LTF, and Data field.

[0111] Applicable RU sizes may be defined depending on the PPDU bandwidth. RUs may be defined to be the same or different for applicable PPDU formats (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU arrangements for HE PPDU and EHT PPDU may be different from each other. The applicable RU size, number of RUs, RU locations, DC (direct current) subcarrier locations and numbers, null subcarrier locations and numbers, and guard subcarrier locations and numbers for each PPDU bandwidth may be referred to as a tone plan. For example, a tone plan for a wide bandwidth may be defined as multiple repetitions of a tone plan for a low bandwidth.

[0112] RUs of various sizes may 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, 4×996-tone RUs, etc. An MRU (multiple RU) is distinct from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs. For example, one MRU may 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. Furthermore, the multiple RUs that make up one MRU may be contiguous or non-contiguous in the frequency domain.

[0113] The specific size of an RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the corresponding number of tones) in this disclosure is not limited and is merely exemplary. Also, in this disclosure, the number of RUs within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) may vary depending on the RU size.

[0114] The names of the fields in the PPDU format of Fig. 7 are merely examples, and the scope of the present disclosure is not limited by the names. In addition, the examples of the present disclosure may be applied not only to the PPDU format illustrated in Fig. 7, but also to a new PPDU format in which some fields are omitted and / or some fields are added based on the PPDU format of Fig. 7.

[0115] Resource Units

[0116] 8 to 10 are diagrams illustrating examples of resource units in a wireless LAN system to which the present disclosure can be applied.

[0117] 8 to 10, a resource unit (RU) defined in a wireless LAN system will be described. An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on the OFDMA technique. An RU may also be defined when transmitting a signal to one STA. An RU may be used for the STF, LTF, data field, etc. of a PPDU.

[0118] 8 to 10, RUs corresponding to different numbers of tones (i.e., subcarriers) may be used to configure some fields of a 20 MHz, 40 MHz, or 80 MHz X-PPDU (X is HE, EHT, etc.). For example, resources may be allocated in units of RUs indicated for the X-STF, X-LTF, and Data fields.

[0119] FIG. 8 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on a 20 MHz band.

[0120] As shown at the top of Figure 8, 26 units (i.e., units corresponding to 26 tones) may be allocated. Six tones may be used as a guard band in the leftmost band of the 20 MHz band, and five tones may be used as a guard band in the rightmost band of the 20 MHz band. Seven DC tones may be inserted into the center band, i.e., the DC band, leaving 26 units corresponding to 13 tones on each side of the DC band. Other bands may be allocated 26 units, 52 units, or 106 units. Each unit may be allocated for a STA or a user.

[0121] The RU arrangement in Figure 8 can be utilized not only in a multiple user (MU) situation but also in a single user (SU) situation, in which case one 242 unit can be used as shown at the bottom of Figure 8. In this case, three DC tones may be inserted.

[0122] In the example of Figure 8, RUs of various sizes, i.e., 26-RU, 52-RU, 106-RU, 242-RU, etc., are illustrated, but the specific sizes of such RUs may be reduced or expanded. Therefore, the specific size of each RU (i.e., the corresponding number of tones) is not limited in the present disclosure and is merely exemplary. Also, in the present disclosure, the number of RUs within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) may vary depending on the size of the RU. The examples of Figures 9 and / or 10 described below are the same as the example of Figure 8 in that the size and / or number of RUs may be changed.

[0123] FIG. 9 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on a 40 MHz band.

[0124] Just as various sizes of RUs are used in the example of Figure 8, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. may be used in the example of Figure 9. In addition, five DC tones may be inserted at the center frequency, 12 tones may be used as a guard band in the leftmost band of the 40 MHz band, and 11 tones may be used as a guard band in the rightmost band of the 40 MHz band.

[0125] Also, as shown in the figure, when used for a single user, 484-RU may be used.

[0126] FIG. 10 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on an 80 MHz band.

[0127] Just as various sizes of RUs are used in the examples of Figures 8 and 9, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc. may be used in the example of Figure 10. Furthermore, in an 80 MHz PPDU, the RU arrangements of the HE PPDU and the EHT PPDU may differ from each other, and the example of Figure 10 shows an example of the RU arrangement for an 80 MHz EHT PPDU. In the example of Figure 10, the HE PPDU and the EHT PPDU are the same in that 12 tones are used as a guard band in the leftmost band of the 80 MHz band and 11 tones are used as a guard band in the rightmost band of the 80 MHz band. In the HE PPDU, seven DC tones are inserted into the DC band, and there are two 26-RUs on each side of the DC band, corresponding to 13 tones. In the EHT PPDU, 23 DC tones are inserted into the DC band, and there are two 26-RUs on each side of the DC band. In the HE PPDU, there is one null subcarrier between the 242-RUs outside the center band. In the EHT PPDU, there are five null subcarriers. In the HE PPDU, one 484-RU does not contain a null subcarrier, but in the EHT PPDU, one 484-RU contains five null subcarriers.

[0128] Also, as shown in the figure, when used for a single user, 996-RU may be used, and in this case, five DC tones are inserted, which is common to both the HE PPDU and the EHT PPDU.

[0129] An EHT PPDU of 160 MHz or more may be configured with multiple 80 MHz sub-blocks in Figure 10. The RU allocation for each 80 MHz sub-block may be the same as the RU allocation for the 80 MHz EHT PPDU in Figure 10. When the 80 MHz sub-blocks of a 160 MHz or 320 MHz EHT PPDU are not punctured and the entire 80 MHz sub-block is used as part of an RU or MRU (Multiple RU), the 80 MHz sub-block can use 996 RUs in Figure 10.

[0130] Here, an MRU corresponds to a group of subcarriers (or tones) composed of multiple RUs, and the multiple RUs constituting an MRU may be RUs of the same size or different sizes. For example, a single MRU may 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. Here, the multiple RUs constituting one MRU may correspond to RUs of small size (e.g., 26, 52, 106) or RUs of large size (e.g., 242, 484, 996, etc.). That is, one MRU including RUs of small size and RUs of large size does not need to be configured / defined. Furthermore, the multiple RUs constituting one MRU may or may not be contiguous in the frequency domain.

[0131] If an 80 MHz sub-block contains RUs with fewer than 996 tones or if portions of the 80 MHz sub-block are punctured, the 80 MHz sub-block may use an RU placement that excludes 996-tone RUs.

[0132] The RUs of the present disclosure may be used for uplink (UL) and / or downlink (DL) communications. For example, when trigger-based UL-MU communications are performed, a STA (e.g., an AP) transmitting a trigger may use trigger information (e.g., a trigger frame or triggered response scheduling (TRS)) to assign 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. The first STA may then transmit a first trigger-based (TB) PPDU based on the first RU, and the second STA may transmit a second TB PPDU based on the second RU. The first and second TB PPDUs may be transmitted to the AP in the same time interval.

[0133] For example, when a DL MU PPDU is configured, a STA (e.g., an AP) transmitting the DL MU PPDU can assign 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., an AP) can transmit the X-STF (e.g., X is HE, EHT, etc.), X-LTF, and Data fields for the first STA using the first RU within one MU PPDU, and the X-STF, X-LTF, and Data fields for the second STA using the second RU. Information regarding the location of the RUs may be signaled in the X-SIG (e.g., X is HE, EHT, U) field of the X-PPDU format.

[0134] PPDU format definition and PPDU transmission / reception method in new operating frequency band

[0135] The above description of the WLAN system may be primarily applied to WLAN systems operating in existing operating frequency bands, such as sub-7 GHz bands (e.g., 2.4 GHz, 5 GHz, or 6 GHz bands). For example, the above-described PPDU format may be primarily applied to WLAN systems operating in sub-7 GHz bands. Furthermore, WLAN systems operating in higher operating frequency bands, such as millimeter wave (mmWave) bands, such as the 60 GHz band, have been defined.

[0136] In this disclosure, a PPDU format is defined that takes into consideration improvements in throughput and efficiency in the mmWave band, including the 60 GHz band (i.e., not limited to the 60 GHz band), and examples of methods for transmitting and receiving PPDUs based on this format are described.

[0137] FIG. 11 is a diagram illustrating an example of the channelization of the millimeter wave (mmWave) band by region to which the present disclosure can be applied.

[0138] The example in Figure 11 shows mmWave bands used in the United States, the European Union, South Korea, Japan, Australia, and China, and the sizes and locations of channels defined in the bands. For example, the bandwidth of each of the six channels may be 2.16 GHz. Also, when bandwidth bonding is applied, up to four unit bandwidths can be bonded to support a maximum bandwidth of 8.64 GHz.

[0139] Furthermore, the bandwidths supported by a wireless LAN system (e.g., an IEEE 802.11ac (VHT)-based system) that conforms to the 1x numerology are 20, 40, 80, and 160 MHz. 64, 128, 256, and 512 subcarrier numbers are defined for the 20, 40, 80, and 160 MHz bandwidths, respectively. A tone plan is also defined for the number and positions of DC subcarriers, guard subcarriers, null subcarriers, pilot subcarriers, etc. The subcarrier spacing is also defined as 312.5 kHz, the OFDM symbol length excluding the cyclic prefix (CP) length is 3.2 us, and the applicable guard intervals are 0.8 us and 0.4 us.

[0140] As described with reference to FIGS. 8 to 10, the bandwidths supported by a WLAN system (e.g., a system based on IEEE 802.11ax (HE) or IEEE 802.11be (EHT)) corresponding to the 4x numerology are 20, 40, 80, 160, and 320 MHz. 256, 512, 1024, 2048, and 4096 subcarrier numbers are defined for the 20, 40, 80, 160, and 320 MHz bandwidths, respectively. Also, RU / MRU tone plans are defined for the number and positions of DC subcarriers, guard subcarriers, null subcarriers, pilot subcarriers, etc. Also, the subcarrier spacing is defined as 78.125 kHz, the OFDM symbol length excluding the CP length is defined as 12.8 us, and the applicable guard intervals are defined as 3.2 us, 1.6 us, and 0.8 us.

[0141] Unlike such existing WLAN systems, technologies under discussion, such as UHR, are being discussed that use sub-7 GHz bands (e.g., 2.4 GHz, 5 GHz, or 6 GHz bands) and / or mmWave bands (e.g., 60 GHz bands) to achieve high data rates and low latency. For example, for specific use cases that require high throughput, the currently defined channel bandwidth alone may be insufficient to meet the requirements, and therefore, transmitting / receiving specific PPDUs in mmWave bands may be considered. In this case, a new PPDU format for the mmWave band needs to be defined / configured.

[0142] In the mmWave band, bandwidth and tone plan may be configured by applying upclocking to the above-mentioned 1x numerology and / or 4x numerology. That is, a new numerology in the mmWave band may be defined based on an N-fold upclocking relationship with the existing 1x numerology or 4x numerology, where N may be a value such as 4, 8, or 10.

[0143] Here, upclocking may refer to an operation in which a sampling time is increased by changing the clock speed to a faster rate, thereby increasing the bandwidth (BW). Here, the sampling time may be defined as 1 / BW. As an example, N-fold upclocking may correspond to an operation in which a sampling time is increased by N times (i.e., 1 / (N*BW)) by changing the clock speed to a faster rate, thereby increasing the bandwidth by N times. Here, N may be referred to as an upclocking factor.

[0144] Specifically, when applying N-fold up-clocking in the mmWave band, the bandwidth is the existing bandwidth * N, the number of subcarriers is the same as the number in the existing bandwidth, the subcarrier spacing is the existing subcarrier spacing * N, and the symbol duration is the existing symbol length / N.

[0145] For example, a new numerology based on an existing 1x numerology (e.g., the 1x numerology in IEEE 802.11ac) may define the following: the bandwidth is one of 20*N, 40*N, 80*N, or 160*N MHz; the subcarrier spacing is 312.5*N kHz; the number of subcarriers is one of 64, 128, 256, or 512; and the OFDM symbol length excluding the guard interval (or CP length) may be defined as 3.2 / N us. Here, possible values ​​of the guard interval may be defined as 0.8 / N and 0.4 / N us. Furthermore, a 160*2N MHz bandwidth (i.e., 1024 subcarriers) in which the 160*N MHz tone plan is repeated twice, or a 160*4N MHz bandwidth (i.e., 2048 subcarriers) in which the 160*N MHz tone plan is repeated four times may be defined.

[0146] For example, a new numerology based on an existing 4x numerology (e.g., the 4x numerology in IEEE 802.11ax / 11be) may define the following: the bandwidth is one of 20*N, 40*N, 80*N, 160*N, or 320*N MHz; the subcarrier spacing is 78.125*N kHz; the number of subcarriers is one of 256, 512, 1024, 2048, or 4096; and the OFDM symbol length excluding the guard interval (or CP length) may be defined as 12.8 / N us. Here, possible values ​​of the guard interval may be defined as 0.8 / N, 1.6 / N, and 3.2 / N us. Furthermore, a 320*2N MHz bandwidth (i.e., 8192 subcarriers) may be defined in which the 320*N MHz tone plan is repeated twice.

[0147] [Embodiment] Hereinafter, a method for defining a PPDU format to be transmitted in the mmWave band based on the above-mentioned numerology will be specifically explained using an example.

[0148] Example 1

[0149] This embodiment relates to a method for defining a basic PPDU format in the mmWave band.

[0150] For example, the PPDU format described in this embodiment may correspond to a PPDU format defined in consideration of a SISO (single-input and single-output) situation.

[0151] A PPDU transmitted in the mmWave band may be defined by a preamble and a data field, where the preamble may or may not include an existing legacy preamble, and if not, may simply have a structure of STF, LTF, SIG, and Data.

[0152] FIG. 12 illustrates an example of a PPDU format in the mmWave band according to an embodiment of the present disclosure.

[0153] Referring to FIG. 12, the PPDU format in the mmWave band may consist of a UHR-STF, a UHR-LTF, a UHR-SIG, and a data field.

[0154] In this regard, the UHR-STF, UHR-LTF, and UHR-SIG described in this disclosure are examples of names referring to STF, LTF, and SIG in next-generation wireless LAN systems, and may be replaced with other names having the same functions.

[0155] In the mmWave band, the interference effect due to beamforming and line of sight (LoS) characteristics is small, so there is no need to define a PPDU format taking into consideration compatibility, interoperability, and / or coexistence with STAs in existing WLAN systems (e.g., STAs / terminals based on the IEEE 802.11ad / ay standard).

[0156] Taking this into consideration, the PPDU format in the mmWave band may be defined as a simple structure of UHR-STF, UHR-LTF, UHR-SIG, and a data field, as shown in FIG.

[0157] Additionally, as mentioned above, a PPDU format may be defined that takes SISO situations into consideration, preferentially, for ease of implementation.

[0158] Below, based on the numerology described above in this disclosure, a specific structure for each field shown in FIG. 12 is proposed.

[0159] (Example 1-1)

[0160] First, when the aforementioned 1x numerology is configured / defined to be reused in the mmWave band, each field may be defined by applying upclocking to the PPDU format structure in a wireless LAN system (e.g., an IEEE 802.11ac (VHT)-based system) corresponding to the 1x numerology.

[0161] For example, in the case of UHR-STF, the final structure may be defined by applying N-fold up-clocking to the VHT-STF defined in each bandwidth (BW) before up-clocking is applied.

[0162] In this case, for coarse carrier frequency offset (CFO) estimation, the UHR-STF may be configured by repeating the VHT-STF twice. Here, the VHT-STF may have a length of 4 us and a structure in which a 0.8 us signal is repeated five times. Therefore, the UHR-STF included in the PPDU format proposed in this embodiment may have a length of 8 / N us.

[0163] For example, in the case of UHR-LTF, the final structure may be defined by applying N-fold up-clocking to VHT-LTF defined in each bandwidth before up-clocking is applied.

[0164] In this regard, in consideration of the SISO situation, the UHR-LTF may be constructed based on the one-symbol VHT-LTF.

[0165] In this case, for fine CFO estimation, the guard interval (GI) in the VHT-LTF may be repeated twice (i.e., GI*2) and located in the front part, and the part excluding the GI in the VHT-LTF (i.e., LTS (long training symbol)) may be repeated twice and located in the rear part, to which N-fold up-clocking may be applied. That is, the UHR-LTF may have a structure of [GI*2+LTS+LTS]. Here, the length of the GI in the VHT-LTF is 0.8 us (or 0.4 us in the case of short GI), and the length of the part excluding the GI, i.e., the LTS, is 3.2 us. Therefore, the length of GI*2 may be 1.6 / N (or 0.8 / N) us, and the length of the LTS may be 3.2 / N us.

[0166] For example, when N-fold up-clocking is applied, the UHR-SIG may be repeated identically in 20*N MHz units. In this case, one symbol of the UHR-SIG may have a length of 4 / N (or 3.6 / N) us, and the UHR-SIG may be (always) fixed to a specific number of symbols. For example, the UHR-SIG may be fixed to two symbols.

[0167] For example, when N-fold up-clocking is applied, one symbol of the data field may have a length of 4 / N (or 3.6 / N) us, and the data field may consist of a variable number of symbols.

[0168] (Example 1-2)

[0169] Next, when the above-mentioned 4x numerology is set / defined to be reused in the mmWave band, each field may be defined by applying up-clocking to the PPDU format structure in a wireless LAN system (e.g., an IEEE 802.11ax (HE) or IEEE 802.11be (EHT)-based system) corresponding to the 4x numerology.

[0170] For example, in the case of UHR-STF, the final structure may be defined by applying N-fold up-clocking to HE-STF or EHT-STF defined in each bandwidth before up-clocking is applied.

[0171] For coarse CFO estimation, the UHR-STF may be configured by repeating the HE-STF or EHT-STF twice. Here, the 1x HE-STF or 1x EHT-STF may have a length of 4 us and a structure in which a 0.8 us signal is repeated five times. Additionally, the 2x HE-STF or 2x EHT-STF may have a length of 8 us and a structure in which a 1.6 us signal is repeated five times.

[0172] Therefore, when based on 1x HE-STF or 1x EHT-STF, the UHR-STF included in the PPDU format proposed in this embodiment may have a length of 8 / N us. In contrast, when based on 2x HE-STF or 2x EHT-STF, the UHR-STF included in the PPDU format proposed in this embodiment may have a length of 16 / N us.

[0173] In this regard, in terms of CFO estimation, it would be preferable for the UHR-STF to be defined based on 1x HE-STF or 1x EHT-STF.

[0174] For example, in the case of UHR-LTF, the final structure may be defined by applying N-fold up-clocking to HE-LTF or EHT-LTF defined in each bandwidth before up-clocking is applied.

[0175] In this regard, in consideration of the SISO situation, the UHR-LTF may be constructed based on the one-symbol HE-LTF or EHT-LTF.

[0176] In this case, for fine CFO estimation, the GI in the HE-LTF or EHT-LTF may be repeated twice (i.e., GI*2) and located in the front part, and the part excluding the GI (i.e., LTS) in the VHT-LTF may be repeated twice and located in the rear part, to which N-fold up-clocking may be applied. That is, the UHR-LTF may have a structure of [GI*2+LTS+LTS]. Here, the length of the GI in the HE-LTF or EHT-LTF is 0.8 us, 1.6 us, or 3.2 us, and the length of the part excluding the GI, i.e., the LTS, is 3.2 us, 6.4 us, or 12.8 us in the 1x / 2x / 4x HE-LTF or EHT-LTF, respectively. Therefore, the length of GI*2 may be 1.6 / N us, 3.2 / N us, or 6.4 / N us, and the length of the LTS may be 3.2 / N us, 6.4 / N us, or 12.8 / N us.

[0177] In this regard, in terms of channel estimation, it would be preferable to define UHR-LTF based on 4x HE-LTF or 4x EHT-LTF. Additionally or alternatively, in terms of CFO estimation, it would be preferable to define UHR-LTF based on 1x HE-LTF or 1x EHT-LTF. Additionally or alternatively, taking into account the trade-off between these two aspects, it would be preferable to define UHR-LTF based on 2x HE-LTF or 2x EHT-LTF.

[0178] For example, when N-fold up-clocking is applied, the UHR-SIG may be repeated in 20*N MHz units. In this case, one symbol of the UHR-SIG may have a length of (GI+12.8) / N us, and the UHR-SIG may be (always) fixed to a specific number of symbols. For example, the GI may be 0.8 us, 1.6 us, or 3.2 us, and the UHR-SIG may be fixed to two symbols.

[0179] For example, when N-fold upclocking is applied, one symbol of the data field may have a length of (GI+12.8) / N us (e.g., GI may be 0.8 us, 1.6 us, or 3.2 us), and the data field may consist of a variable number of symbols.

[0180] Example 2

[0181] This embodiment relates to a method for defining a PPDU format when MIMO (multiple-input and multiple-output) precoding transmission is considered in the mmWave band.

[0182] For example, the PPDU format described in this embodiment corresponds to a PPDU format defined taking into account MIMO conditions, and the above-mentioned MIMO precoding transmission may be based on hybrid beamforming (i.e., analog beamforming and digital beamforming).

[0183] FIG. 13 illustrates another example of a PPDU format in the mmWave band according to an embodiment of the present disclosure.

[0184] Referring to FIG. 13, the PPDU format in the mmWave band may consist of UHR-STF, UHR-LTF, UHR-SIG, M-UHR-STF, M-UHR-LTF, and a data field.

[0185] In this regard, UHR-STF, UHR-LTF, UHR-SIG, M-UHR-STF, and M-UHR-LTF described in this disclosure are examples of names referring to STF, LTF, SIG, M-STF, and M-LTF in next-generation wireless LAN systems, and may be replaced with other names having the same functions.

[0186] Here, the contents described in Example 1 may be used / applied equally to the UHR-STF, UHR-LTF, and UHR-SIG. That is, the UHR-STF and UHR-LTF can use the same numerology and the structure proposed in the SISO situation.

[0187] In relation to the application of beamforming, digital beamforming may be applied starting from the M-UHR-STF and subsequent fields, while analog beamforming may be applied starting from the M-UHR-STF and subsequent fields, or alternatively, may be applied starting from the very beginning of the PPDU format.

[0188] The M-UHR-STF may be needed to estimate the AGC, and the M-UHR-LTF may be needed for channel estimation for the MIMO streams.

[0189] Below, based on the numerology described above in this disclosure, we propose a specific structure for the M-UHR-STF, M-UHR-LTF, and data field shown in Figure 13.

[0190] Example 2-1

[0191] First, when the aforementioned 1x numerology is configured / defined to be reused in the mmWave band, each field may be defined by applying upclocking to the PPDU format structure in a wireless LAN system (e.g., an IEEE 802.11ac (VHT)-based system) corresponding to the 1x numerology.

[0192] For example, in the case of M-UHR-STF, the final structure may be defined by applying N-fold up-clocking to the VHT-STF defined for each bandwidth before up-clocking. Here, the VHT-STF may have a length of 4 us and a structure in which a 0.8 us signal is repeated five times. Therefore, the M-UHR-STF included in the PPDU format proposed in this embodiment may have a length of 4 / N us.

[0193] For example, in the case of M-UHR-LTF, the final structure may be defined by applying N-fold up-clocking to the VHT-LTF defined in each bandwidth before up-clocking is applied.

[0194] In this regard, in a MIMO situation, the number of symbols of the M-UHR-LTF may be defined in a predefined manner (e.g., the manner defined in IEEE 802.11ac) depending on the stream to be transmitted, and the length of each symbol may be 4 / N (or 3.6 / N) us.

[0195] For example, when N-fold up-clocking is applied, one symbol of the data field may have a length of 4 / N (or 3.6 / N) us, and the data field may consist of a variable number of symbols.

[0196] (Example 2-2)

[0197] Next, when the above-mentioned 4x numerology is set / defined to be reused in the mmWave band, each field may be defined by applying up-clocking to the PPDU format structure in a wireless LAN system (e.g., an IEEE 802.11ax (HE) or IEEE 802.11be (EHT)-based system) corresponding to the 4x numerology.

[0198] For example, in the case of M-UHR-STF, the final structure may be defined by applying N-fold up-clocking to the HE-STF or EHT-STF defined in each bandwidth before up-clocking is applied.

[0199] Here, the 1x HE-STF or 1x EHT-STF may have a length of 4 us and a structure in which a 0.8 us signal is repeated five times. Additionally, the 2x HE-STF or 2x EHT-STF may have a length of 8 us and a structure in which a 1.6 us signal is repeated five times.

[0200] Therefore, when based on 1x HE-STF or 1x EHT-STF, the M-UHR-STF included in the PPDU format proposed in this embodiment may have a length of 4 / N us. In contrast, when based on 2x HE-STF or 2x EHT-STF, the UHR-STF included in the PPDU format proposed in this embodiment may have a length of 8 / N us.

[0201] In this regard, if only downlink conditions are considered, it would be preferable that the M-UHR-STF be defined based on 1x HE-STF or 1x EHT-STF.

[0202] For example, in the case of M-UHR-LTF, the final structure may be defined by applying N-fold up-clocking to the HE-LTF or EHT-LTF defined in each bandwidth before up-clocking is applied.

[0203] In this regard, in a MIMO situation, the number of symbols in M-UHR-LTF may be defined in a predefined manner (for example, the manner defined in IEEE 802.11ac) depending on the stream to be transmitted. In this case, the length of the GI in each symbol is 0.8 us, 1.6 us, or 3.2 us, and the length of the part excluding the GI, i.e., the LTS, is 3.2 us, 6.4 us, or 12.8 us in 1x / 2x / 4x HE-LTF or EHT-LTF, respectively.

[0204] In terms of channel estimation, it is preferable that the M-UHR-LTF be defined based on 4x HE-LTF or 4x EHT-LTF. Additionally or alternatively, in terms of overhead reduction and robustness against CFO, it is preferable that the M-UHR-LTF be defined based on 1x HE-LTF or 1x EHT-LTF. Additionally or alternatively, taking into account the trade-off between these two aspects, it is preferable that the M-UHR-LTF be defined based on 2x HE-LTF or 2x EHT-LTF.

[0205] For example, when N-fold upclocking is applied, one symbol of the data field may have a length of (GI+12.8) / N us (e.g., GI may be 0.8 us, 1.6 us, or 3.2 us), and the data field may consist of a variable number of symbols.

[0206] Additionally or alternatively, in a MIMO transmission situation where only analog beamforming is applied, the same PPDU format may be used as in a situation where hybrid beamforming is applied as described above.

[0207] For example, this may be for a situation where analog beamforming can be applied in fields starting from the M-UHR-STF and thereafter. Additionally, in a SISO analog beamforming situation, a PPDU format may be defined with a structure similar to the PPDU format described above, and in this case, analog beamforming may be configured / defined to be applied in fields starting from the M-UHR-STF and thereafter.

[0208] Additionally or alternatively, in MIMO transmission situations where only analog beamforming is applied, a method of omitting the M-UHR-STF from the PPDU format described above may be considered.

[0209] FIG. 14 illustrates yet another example of a PPDU format in the mmWave band according to an embodiment of the present disclosure.

[0210] 14, the PPDU format in the mmWave band may be configured with a UHR-STF, a UHR-LTF, a UHR-SIG, an M-UHR-LTF, and a data field. In this case, except for the description regarding the number of symbols in the M-UHR-LTF, the specific structure of each field may be the same as that described in FIG. 13.

[0211] In this case, analog beamforming may be set / defined to be applied from the very beginning of the PPDU format in consideration of performance aspects. Additionally, a PPDU format may be defined with a similar structure in a SISO analog beamforming situation, and in this case, analog beamforming may be set / defined to be applied starting from the very beginning of the PPDU format.

[0212] In the PPDU format shown in Figure 14, UHR-LTF may be used for channel estimation for CFO estimation and UHR-SIG decoding, and M-UHR-LTF may be used for channel estimation or channel estimation performance improvement for decoding of the data field.

[0213] Here, the number of symbols of the M-UHR-LTF may be determined by the number of streams, including the number of symbols of one UHR-LTF. For example, when two streams are transmitted, the M-UHR-LTF may be composed of one symbol, and channel state estimation for decoding the two streams may be performed by combining the UHR-LTF and the M-UHR-LTF.

[0214] Additionally or alternatively, in the various PPDU format structures proposed in this disclosure, a scheme may be considered in which fields up to the UHR-SIG (e.g., UHR-STF, UHR-LTF, UHR-SIG) are configured based on 1x numerology, and subsequent fields (e.g., M-UHR-STF, M-UHR-LTF, data field) are configured based on 4x numerology. In this case, beamforming or the like may be applied starting from the fields after the UHR-SIG (e.g., M-UHR-STF, M-UHR-LTF, data field) and transmitted.

[0215] Additionally or alternatively, for PPDU unification and implementation simplicity, a single PPDU format may be defined, in which case the PPDU format proposed in a MIMO transmission situation where hybrid beamforming is applied (e.g., the PPDU format in FIG. 13) may be considered as the single PPDU format.

[0216] Additionally or alternatively, a specific training field may be inserted at the end of the PPDU format for beam refinement.

[0217] Hereinafter, the operation of the STA according to the above-described embodiment of the present disclosure will be described with reference to Figures 15 and 16. That is, the examples in Figures 15 and 16 may correspond to some of the various examples of the present disclosure.

[0218] FIG. 15 illustrates an operation of the first STA according to an embodiment of the present disclosure.

[0219] The first STA may configure a PPDU in a first operating frequency band (S1510).

[0220] In this regard, the first operating frequency band may be the mmWave band or the 60 GHz band, and the PPDU configured in step S1510 may be based on the PPDU format for the mmWave band described above in this disclosure.

[0221] For example, the first PPDU format for the PPDU may include a first short training field (STF), a first long training field (LTF), a signal (SIG) field, and a data field. In this case, the first PPDU format may be defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band (e.g., a sub-7 GHz band, i.e., a 2.4 GHz, 5 GHz, or 6 GHz band).

[0222] Specifically, the first STF structure (e.g., the UHR-STF structure in the present disclosure) may be constructed by repeating the second STF structure (e.g., the VHT-STF structure) included in the second PPDU format twice and then applying an up-clocking factor (e.g., N). For example, the length of the first STF structure may be 8 / N us.

[0223] Additionally, the first LTF structure (e.g., the UHR-LTF structure in the present disclosure) may be configured by repeating the guard interval (GI) of the second LTF structure included in the second PPDU format twice, followed by repeating the portion of the second LTF structure excluding the GI twice, and then applying an up-clocking factor (e.g., N). For example, the length of the GI in the first LTF structure may be 1.6 / N or 0.8 / N microseconds (us), and the length of the portion of the first LTF structure excluding the GI may be 2*3.2 / N us.

[0224] For the above-mentioned PPDU, the bandwidth may be any one of 20*N, 40*N, 80*N, or 160*N MHz, the subcarrier spacing may be 312.5*N kHz, the number of subcarriers may be any one of 64, 128, 256, or 512, and the OFDM (orthogonal frequency division multiplexing) symbol length excluding the CP (cyclic prefix) length may be 3.2 / N us, where N corresponds to the value of the up-clocking element.

[0225] Additionally, the SIG field (e.g., the UHR-SIG field in the present disclosure) may be identically repeated in units of 20*N MHz in the frequency domain, and the symbol length of the SIG field may be 4 / N or 3.6 / N us, where N corresponds to the value of the up-clocking element. Here, the SIG field may be composed of two symbols with a symbol length of 4 / N or 3.6 / N us.

[0226] Additionally, the data field may consist of one or more symbols with a symbol length of 4 / N or 3.6 / N us.

[0227] Additionally or alternatively, a case may be considered in which a beamforming-based multiple-input and multiple-output (MIMO) technique is applied to the transmission and reception of PPDUs in S1510.

[0228] In this case, the first PPDU format may further include a first field and a second field associated with a MIMO scheme. The structure of the first field may be defined by applying an up-clocking element based on the second SFT structure, and the structure of the second field may be defined by applying the up-clocking based on the second LTF structure. The first and second fields may be positioned following the signal field in the first PPDU format, and beamforming may be defined to be applicable starting from the first field to subsequent fields. Additionally, the number of symbols constituting the second field may be determined based on the number of spatial streams for the PPDU.

[0229] Alternatively, the first PPDU format may further include one specific field associated with the MIMO technique. The structure of the specific field may be defined by applying up-clocking based on the second LTF structure described above. The specific field may be positioned following the signal field in the first PPDU format, and beamforming may be defined to be applicable starting from the very beginning of the first PPDU format. Additionally, the number of symbols constituting the specific field may be determined based on the number of symbols in the first LTF described above and the number of spatial streams for the PPDU.

[0230] Thereafter, the first STA may transmit the PPDU configured as described above to the second STA in the first operating frequency band (S1520).

[0231] The method performed by the first STA described in the example of Figure 15 may be performed by the first device 100 of Figure 1. For example, the one or more processors 102 of the first device 100 of Figure 1 may be configured to construct a PPDU in a first operating frequency band and transmit the constructed PPDU to the second STA 200 via the one or more transceivers 106.

[0232] For example, as described above, one or more processors 102 of the first device 100 may encode the first STF, the first LTF, the SIG field, the MIMO technique related field, and / or the data field to construct a PPDU in the mmWave band.

[0233] It should be noted that the one or more memories 104 of the first device 100 may store instructions for performing the method described in the example of FIG. 12 or the examples below when executed by the one or more processors 102.

[0234] FIG. 16 illustrates an operation of the second STA according to an embodiment of the present disclosure.

[0235] The second STA can receive the PPDU from the first STA in the first operating frequency band (S1610).

[0236] In this regard, the first operating frequency band may be the mmWave band or the 60 GHz band, and the PPDU received in step S1610 may be based on the PPDU format for the mmWave band described above in this disclosure.

[0237] For example, the first PPDU format for the PPDU may include a first short training field (STF), a first long training field (LTF), a signal (SIG) field, and a data field. In this case, the first PPDU format may be defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band (e.g., a sub-7 GHz band, i.e., a 2.4 GHz, 5 GHz, or 6 GHz band).

[0238] Specifically, the first STF structure (e.g., the UHR-STF structure in the present disclosure) may be configured by repeating the second STF structure (e.g., the VHT-STF structure) included in the second PPDU format twice, followed by applying an up-clocking element (e.g., N). Additionally, the first LTF structure (e.g., the UHR-LTF structure in the present disclosure) may be configured by repeating the guard interval (GI) of the second LTF structure included in the second PPDU format twice, followed by repeating the portion of the second LTF structure excluding the GI twice, followed by applying an up-clocking element (e.g., N).

[0239] The second STA can process the received PPDU (S1620).

[0240] For example, processing the PPDU may include obtaining information contained in each of the fields of the received PPDU based on any one of various predefined PPDU formats (e.g., a PPDU format in the mmWave band).

[0241] In the example of Figure 16, the first PPDU format and the specific contents of each field constituting the PPDU format are the same as those explained in the example of Figure 15, and duplicate explanations will be omitted.

[0242] The method performed by the second STA described in the example of Figure 16 may be performed by the second device 200 of Figure 1. For example, the one or more processors 202 of the second device 200 of Figure 1 may be configured to receive PPDUs from the first STA 100 via the one or more transceivers 206 and may be configured to process the received PPDUs.

[0243] For example, the one or more processors 202 of the second device 200 may be configured to decode the received PPDU based on a PPDU format defined for the mmWave band (e.g., the first PPDU format described above) and obtain information contained in the first STF, the second LTF, the SIG field, the MIMO technique related field, and / or the data field.

[0244] It should be noted that the one or more memories 204 of the second device 200 may store instructions for performing the method described in the example of FIG. 13 or in the examples below when executed by the one or more processors 202.

[0245] Existing wireless LAN systems do not define specific content constituting a PPDU format in the mmWave band. In this regard, the method proposed in this disclosure relates to a method for defining a PPDU format in the mmWave band by considering the reuse of existing numerology (e.g., 1x numerology, 4x numerology) and applying an up-clocking multiple to it. In particular, the method proposed in this disclosure has a novel feature of designing the structure of each field included in the PPDU format in consideration of aspects of coarse CFO estimation and / or fine CFO estimation. The method proposed in this disclosure can achieve new effects such as improving throughput and / or efficiency in a newly defined operating band (e.g., the mmWave band).

[0246] The embodiments described above are combinations of the components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless otherwise explicitly stated. Each component or feature may be implemented without being combined with other components or features. It is also possible to combine some components and / or features to form embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components or features of another embodiment. It is clear that claims that do not have an explicit reference relationship in the claims may be combined to form embodiments, or may be included as new claims by amendment after filing.

[0247] It is obvious to those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted as limiting in any respect, but should be considered as illustrative. The scope of the present disclosure should be determined by reasonable interpretation of the appended claims, and any modifications within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0248] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause a device or computer to perform operations according to the methods of various embodiments, as well as non-transitory computer-readable media on which such software or instructions are stored and executable on a device or computer. Instructions usable for programming a processing system to perform features described in this disclosure may be stored on or in a storage medium or computer-readable storage medium, and computer program products including such storage media may be used to embody features described in this disclosure. Storage media may include high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, but are not limited to, non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. Memory optionally includes one or more storage devices located remotely from the processor. Memory, or alternatively, non-volatile memory devices within memory, comprise non-transitory computer-readable storage media. The features described in this disclosure may be embodied in software and / or firmware stored on any one of a number of machine-readable media and capable of controlling the hardware of a processing system and allowing the processing system to interact with other mechanisms that utilize the results of embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0249] [Industrial Applicability] The method proposed in this disclosure has been described mainly as being applied to an IEEE 802.11-based system, but it can also be applied to various wireless LANs or wireless communication systems other than the IEEE 802.11-based system.

[0250] [Claims at the time of international application] [Claim 1] 1. A method performed by a first station (STA) in a wireless LAN system, comprising: The method comprises: forming a physical layer protocol data unit (PPDU) in a first operating frequency band; transmitting the PPDU to a second STA; The first PPDU format for the PPDU is composed of a first STF (short training field), a first LTF (long training field), a signal (SIG) field, and a data field; the first PPDU format is defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band; The first STF structure is configured by repeating the second STF structure included in the second PPDU format twice and then applying the up-clocking element; The method of claim 1, wherein the first LTF structure is configured by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, followed by repeating a portion of the second LTF structure excluding the GI twice, and then applying the up-clocking element. [Claim 2] In the first LTF structure, the length of GI is 1.6 / N or 0.8 / N microseconds (us), The length of the first LTF structure excluding the GI is 2*3.2 / N us; The method of claim 1 , wherein N corresponds to a value of the up-clocking element. [Claim 3] the length of the first STF structure is 8 / N us; The method of claim 1 , wherein N corresponds to a value of the up-clocking element. [Claim 4] For the PPDU, the bandwidth is one of 20*N, 40*N, 80*N, or 160*N MHz; The subcarrier spacing is 312.5*N kHz, The number of subcarriers is one of 64, 128, 256, or 512; The OFDM (orthogonal frequency division multiplexing) symbol length, excluding the CP (cyclic prefix) length, is 3.2 / N us. The method of claim 1 , wherein N corresponds to a value of the up-clocking element. [Claim 5] The second STF structure corresponds to a VHT (very high throughput)-STF structure, The method of claim 1 , wherein the second LTF structure corresponds to a VHT-LTF structure. [Claim 6] The SIG field is repeated identically in units of 20*N MHz in the frequency domain, The symbol length of the SIG field is 4 / N or 3.6 / N us; The method of claim 1 , wherein N corresponds to a value of the up-clocking element. [Claim 7] The method of claim 6 , wherein the SIG field consists of two symbols having the symbol length. [Claim 8] The method of claim 1 , wherein the data field is composed of one or more symbols having a symbol length of 4 / N or 3.6 / N us. [Claim 9] Based on the application of a beamforming-based MIMO (multiple-input and multiple-output) technique to the transmission and reception of the PPDU, The first PPDU format further includes a first field and a second field associated with the MIMO scheme, a structure of the first field is defined by applying the up-clocking element based on the second SFT structure; The method of claim 1 , wherein the structure of the second field is defined by applying the up-clocking based on the second LTF structure. [Claim 10] the first field and the second field are located following the signal field in the first PPDU format, The method of claim 9 , wherein the beamforming is defined applicatively starting from the first field. [Claim 11] The method of claim 9, wherein the number of symbols constituting the second field is determined based on the number of spatial streams for the PPDU. [Claim 12] Based on the beamforming-based MIMO technique being applied to the transmission and reception of the PPDU, The first PPDU format further includes a specific field associated with the MIMO scheme, The method of claim 1 , wherein the structure of the specific field is defined by applying the up-clocking based on the second LTF structure. [Claim 13] The specific field is located following the signal field in the first PPDU format, The method of claim 12 , wherein the beamforming is defined applicable starting from the very beginning of the first PPDU format. [Claim 14] The method according to claim 12, wherein the number of symbols constituting the specific field is determined based on the number of symbols of the first LTF and the number of spatial streams for the PPDU. [Claim 15] The first operating frequency band corresponds to a millimeter wave (mmWave) band or a 60 GHz band; The method of claim 1 , wherein the second operating frequency band corresponds to one of a 2.4 GHz band, a 5 GHz band, or a 6 GHz band. [Claim 16] A first station (STA) device in a wireless LAN system, The device comprises: one or more transceivers; one or more processors coupled to the one or more transceivers; the one or more processors: Configuring a physical layer protocol data unit (PPDU) in a first operating frequency band; and transmitting the PPDU to a second STA; The first PPDU format for the PPDU is composed of a first STF (short training field), a first LTF (long training field), a signal (SIG) field, and a data field; the first PPDU format is defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band; The first STF structure is configured by repeating the second STF structure included in the second PPDU format twice and then applying the up-clocking element; The first LTF structure is configured by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, followed by repeating a portion of the second LTF structure excluding the GI twice, and then applying the up-clocking element. [Claim 17] 1. A method performed by a second station (STA) in a wireless LAN system, comprising: The method comprises: receiving a physical layer protocol data unit (PPDU) from a first STA in a first operating frequency band; processing the PPDU; The first PPDU format for the PPDU is composed of a first STF (short training field), a first LTF (long training field), a signal (SIG) field, and a data field; the first PPDU format is defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band; The first STF structure is configured by repeating the second STF structure included in the second PPDU format twice and then applying the up-clocking element; The method of claim 1, wherein the first LTF structure is configured by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, followed by repeating a portion of the second LTF structure excluding the GI twice, and then applying the up-clocking element. [Claim 18] A second station (STA) device in a wireless LAN system, The device comprises: one or more transceivers; one or more processors coupled to the one or more transceivers; the one or more processors: Receive a physical layer protocol data unit (PPDU) from a first STA in a first operating frequency band; and processing the PPDU. The first PPDU format for the PPDU is composed of a first STF (short training field), a first LTF (long training field), a signal (SIG) field, and a data field; the first PPDU format is defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band; The first STF structure is configured by repeating the second STF structure included in the second PPDU format twice and then applying the up-clocking element; The first LTF structure is configured by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, followed by repeating a portion of the second LTF structure excluding the GI twice, and then applying the up-clocking element. [Claim 19] 1. A processing unit configured to control a station (STA) in a wireless LAN system, comprising: The processing unit comprises: one or more processors; and one or more computer memories operably coupled to the one or more processors and storing instructions for performing the method of any one of claims 1 to 15 when executed by the one or more processors. [Claim 20] one or more non-transitory computer-readable media storing one or more instructions, A computer-readable medium in which the one or more instructions are executed by one or more processors to control a station (STA) device in a wireless LAN system to perform the method of any one of claims 1 to 15.

Claims

1. 1. A method performed by a first station (STA) in a wireless LAN system, comprising: The method comprises: constructing a physical layer protocol data unit (PPDU) in a first operating frequency band; transmitting the PPDU to a second STA; The first PPDU format for the PPDU consists of a first STF (short training field), a first LTF (long training field), a signal (SIG) field, and a data field; the first PPDU format is defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band; The first STF structure is constructed by repeating the second STF structure included in the second PPDU format twice and then applying the up-clocking element; The first LTF structure is constructed by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, and then repeating a portion of the second LTF structure excluding the GI twice, and then applying the up-clocking element.

2. In the first LTF structure, the length of the GI is 1.6 / N or 0.8 / N microseconds (us), The length of the first LTF structure excluding GI is 2*3.2 / N us, The method of claim 1 , wherein N corresponds to the value of the up-clocking element.

3. The length of the first STF structure is 8 / N us; The method of claim 1 , wherein N corresponds to the value of the up-clocking element.

4. For the PPDU, the bandwidth is one of 20*N, 40*N, 80*N, or 160*N MHz; The subcarrier spacing is 312.5*N kHz, The number of subcarriers is one of 64, 128, 256, or 512; The length of an orthogonal frequency division multiplexing (OFDM) symbol excluding the cyclic prefix (CP) length is 3.2 / N us, The method of claim 1 , wherein N corresponds to the value of the up-clocking element.

5. The second STF structure corresponds to a VHT (very high throughput)-STF structure, The method of claim 1 , wherein the second LTF structure corresponds to a VHT-LTF structure.

6. The SIG field is repeated identically in units of 20*N MHz in the frequency domain, The symbol length of the SIG field is 4 / N or 3.6 / N us; The method of claim 1 , wherein N corresponds to the value of the up-clocking element.

7. The method of claim 6 , wherein the SIG field consists of two symbols having the symbol length.

8. The method of claim 1 , wherein the data field is composed of one or more symbols having a symbol length of 4 / N or 3.6 / N us.

9. Based on the application of a beamforming-based multiple-input and multiple-output (MIMO) technique to the transmission and reception of the PPDU, the first PPDU format further includes a first field and a second field associated with the MIMO scheme; a structure of the first field is defined by applying the up-clocking element based on the second SFT structure; The method of claim 1 , wherein the structure of the second field is defined by applying the up-clocking based on the second LTF structure.

10. the first field and the second field are located following the SIGNAL field in the first PPDU format, The method of claim 9 , wherein the beamforming is defined applicatively starting from the first field.

11. The method of claim 9, wherein the number of symbols constituting the second field is determined based on the number of spatial streams for the PPDU.

12. Based on the fact that a beamforming-based MIMO technique is applied to the transmission and reception of the PPDU, The first PPDU format further includes a specific field associated with the MIMO scheme, The method of claim 1 , wherein the structure of the specific field is defined by applying the up-clocking based on the second LTF structure.

13. The specific field is located following the SIGNAL field in the first PPDU format, The method of claim 12 , wherein the beamforming is defined applicable starting from the very beginning of the first PPDU format.

14. The method of claim 12, wherein the number of symbols constituting the specific field is determined based on the number of symbols in the first LTF and the number of spatial streams for the PPDU.

15. The first operating frequency band corresponds to a millimeter wave (mmWave) band or a 60 GHz band; The method of claim 1 , wherein the second operating frequency band corresponds to one of a 2.4 GHz band, a 5 GHz band, or a 6 GHz band.

16. A first station (STA) device in a wireless LAN system, The device comprises: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: Constructing a physical layer protocol data unit (PPDU) in a first operating frequency band; The PPDU is transmitted to a second STA; The first PPDU format for the PPDU consists of a first STF (short training field), a first LTF (long training field), a signal (SIG) field, and a data field; the first PPDU format is defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band; The first STF structure is constructed by repeating the second STF structure included in the second PPDU format twice and then applying the up-clocking element; The first LTF structure is configured by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, and then repeating a portion of the second LTF structure excluding the GI twice, and then applying the up-clocking element.

17. 1. A method performed by a second station (STA) in a wireless LAN system, comprising: The method comprises: receiving a physical layer protocol data unit (PPDU) from a first STA in a first operating frequency band; processing the PPDU; The first PPDU format for the PPDU consists of a first STF (short training field), a first LTF (long training field), a signal (SIG) field, and a data field; the first PPDU format is defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band; The first STF structure is constructed by repeating the second STF structure included in the second PPDU format twice and then applying the up-clocking element; The first LTF structure is constructed by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, and then repeating a portion of the second LTF structure excluding the GI twice, and then applying the up-clocking element.

18. A second station (STA) device in a wireless LAN system, The device comprises: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: Receive a physical layer protocol data unit (PPDU) from a first STA in a first operating frequency band; and processing the PPDU; The first PPDU format for the PPDU consists of a first STF (short training field), a first LTF (long training field), a signal (SIG) field, and a data field; the first PPDU format is defined by applying an upclocking factor based on a second PPDU format defined for a second operating frequency band; The first STF structure is constructed by repeating the second STF structure included in the second PPDU format twice and then applying the up-clocking element; The first LTF structure is configured by repeating a guard interval (GI) of a second LTF structure included in the second PPDU format twice, and then repeating a portion of the second LTF structure excluding the GI twice, and then applying the up-clocking element.

19. 1. A processing unit configured to control a station (STA) in a wireless LAN system, comprising: The processing unit comprises: one or more processors; and one or more computer memories operably coupled to the one or more processors and storing instructions for performing the method of any one of claims 1 to 15 when executed by the one or more processors.

20. one or more non-transitory computer-readable media storing one or more instructions, The one or more instructions are executed by one or more processors, and a station (STA) device in a wireless LAN system to perform the method according to any one of claims 1 to 15.

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