Distributed resource unit tone plan and pilot tone-based transmission or reception method and apparatus in a wireless LAN system

Abstract

A transmission or reception method and apparatus based on a distributed resource unit tone plan and pilot tones in a wireless local area network (WLAN) system are disclosed. According to one embodiment of the present disclosure, the method, performed by a first station (STA) in a wireless local area network (WLAN) system, may include generating a physical layer protocol data unit (PPDU) including one or more fields, the one or more fields being mapped onto one or more distributed resource units (DRUs); and transmitting the PPDU to one or more second STAs over a bandwidth including a 40 MHz channel. Based on the one or more DRUs including a 26-tone DRU, the 26-tone DRU may be any one of 18 predefined 26-tone DRUs. The pilot tones of each of the 18 predefined 26-tone DRUs may be the seventh-lowest subcarrier and the seventh-highest subcarrier among the subcarriers included in one 26-tone DRU.

Description

[Technical Field]

[0001] The present disclosure relates to a method and apparatus for transmitting or receiving based on a distributed resource unit tone plan and pilot tones 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. In addition, 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] A technical problem of the present disclosure is to provide a transmission or reception method and apparatus based on a distributed resource unit tone plan and pilot tones in a wireless LAN system.

[0005] 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]

[0006] A method performed by a first station (STA) in a wireless local area network (WLAN) system according to one embodiment of the present disclosure may include (may comprise; may configure; may establish; may configure; may encompass; may contain; may have) a step of generating a physical layer protocol data unit (PPDU) including one or more fields, the one or more fields being mapped onto one or more distributed resource units (DRUs); and (may comprise; may have) a step of transmitting the PPDU to one or more second STAs over a bandwidth including a 40 MHz channel. Based on the one or more DRUs including a 26-tone DRU, the 26-tone DRU may be any one of 18 predefined 26-tone DRUs. The pilot tones of each of the 18 predefined 26-tone DRUs may be the 7th-lowest subcarrier and the 7th-highest subcarrier among the subcarriers included in one 26-tone DRU.

[0007] A method performed by a second station (STA) in a wireless local area network (WLAN) system according to a further aspect of the present disclosure may include receiving a physical layer protocol data unit (PPDU) including one or more fields on a bandwidth including a 40 MHz channel from a first STA, and decoding the one or more fields mapped onto one or more distributed resource units (DRUs). Based on the one or more DRUs including a 26-tone DRU, the 26-tone DRU may be any one of 18 previously defined 26-tone DRUs. The pilot tones of each of the 18 previously defined 26-tone DRUs may be the seventh-lowest subcarrier and the seventh-highest subcarrier among the subcarriers included in one 26-tone DRU. [Effects of the Invention]

[0008] According to the present disclosure, a transmission or reception method and apparatus based on a distributed resource unit tone plan and pilot tones in a wireless LAN system can be provided.

[0009] 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]

[0010] 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 8-10] FIG. 1 is a diagram illustrating an example of a resource unit of a wireless LAN system to which the present disclosure can be applied. [Figure 11] FIG. 1 is a diagram illustrating an example of a DRU to which the present disclosure can be applied. [Figure 12] FIG. 10 illustrates an exemplary format of a trigger frame to which the present disclosure can be applied. [Figure 13] A figure for explaining an example of a DRU tone plan and pilot tone-based PPDU reception method of a first STA according to the present disclosure. [Figure 14] A figure for explaining an example of a DRU tone plan and pilot tone-based PPDU transmission method of a second STA according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] 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.

[0013] In this 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 this disclosure, the terms "comprise" or "have" specify the presence of a stated feature, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0014] 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.

[0015] 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.

[0016] 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 be applied to a wireless LAN based on the newly proposed IEEE 802.11bn (or UHR) standard. Furthermore, the examples of the present disclosure may be applied to a wireless LAN based on a next-generation standard after IEEE 802.11bn. Furthermore, the examples of the present disclosure may 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 LTE (Long Term Evolution) series technology and the 5G NR (New Radio) series technology of the 3GPP (3rd Generation Partnership Project: registered trademark; the same applies hereinafter) standard.

[0017] Below, technical features to which the examples of the present disclosure can be applied will be described.

[0018] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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).

[0023] 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.

[0024] 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.

[0025] The hardware elements of the devices 100, 200 are described in more detail below. Without limitation, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY and MAC). The one or more processors 102, 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in this disclosure. The one or more processors 102, 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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 / bn, 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.

[0030] 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.

[0031] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0032] 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.

[0033] The most basic type of BSS in a wireless LAN, ignoring the DS shown in FIG. 2, 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 wireless LAN, 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.

[0034] 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).

[0035] 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.

[0036] 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.

[0037] 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).

[0038] 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.

[0039] Data transmitted from one of the STAs associated with an AP to the STA address of that 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.

[0040] In the above-described DS structure, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0041] 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.

[0042] 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.

[0043] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0044] 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.

[0045] 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.

[0046] 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).

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] FIG. 4 is a diagram illustrating a backoff process to which the present disclosure can be applied.

[0057] 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.

[0058] 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).

[0059] An operation based on a 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 wait for the corresponding slot time before attempting transmission. The random backoff count has a pseudo-random integer value and may be determined to be one of the values ​​ranging from 0 to CW. Here, CW is a contention window parameter value. The CW parameter is initially set to CWmin, but can double 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, the CW parameter is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are preferably set to 2n-1 (n=0, 1, 2, ...).

[0060] 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.

[0061] 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.

[0062] 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, and if it is a response frame of a previous frame, it is transmitted without a backoff after a short IFS (SIFS). The type and subtype of a frame may be identified by the type field and subtype field in the Frame Control (FC) field.

[0063] 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.

[0064] FIG. 5 is a diagram for explaining a CSMA / CA base frame transmission operation to which the present disclosure can be applied.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] Thus, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, a PHY layer protocol data unit (PPDU) frame format is defined.

[0075] 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 Legacy-SIG (L-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.)), etc. may be included between the L-SIG field and the Data field. More specific details will be described later with reference to FIG.

[0076] 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.

[0077] The SIG field may contain various information related to PPDU transmission and reception. For example, the L-SIG field may be composed of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may contain information regarding the modulation and coding 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 non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDU, the value of the Length field may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0078] 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.

[0079] 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.

[0080] 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 of the Address subfields may be omitted. The MAC header includes Sequence Control, QoS Control, and HT Control subfields. For specific contents of each subfield of the MAC header, please refer to the IEEE 802.11 standard document.

[0081] 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).

[0082] 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.

[0083] 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)).

[0084] 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).

[0085] 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)).

[0086] 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 8 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 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 that the received PPDU is an HE PPDU or an EHT PPDU (described later).

[0087] 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 RL-SIG following an L-SIG, but it may also include a U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulation fields. Also, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as pre-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0092] 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.

[0093] 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.

[0094] 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. 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.

[0095] The A-bit information transmitted by the U-SIG can 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.

[0096] 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.

[0097] 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.

[0098] For example, the version dependent bits of the U-SIG may include information that directly or indirectly indicates the type of PPDU (eg, SU PPDU, MU PPDU, TB PPDU, etc.).

[0099] Information necessary for transmitting and receiving a PPDU may be included in the U-SIG. For example, the U-SIG may further include information about the bandwidth, information about an MCS scheme to be applied to a non-legacy SIG (e.g., an EHT-SIG or a 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.

[0100] Some of the information necessary for transmitting and receiving a PPDU 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.

[0101] Preamble puncturing may refer to the transmission of a PPDU in which no signal is present in one or more frequency units in the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to PPDU bandwidths equal to or larger than a predetermined size.

[0102] 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may contain control information for receiving STAs. Non-legacy SIGs may be transmitted in at least one symbol, and one symbol may have a length of 4 us. 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.).

[0103] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include common fields and user-specific fields, which may be coded separately.

[0104] 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 can 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 can receive the PPDU (e.g., the data field of the PPDU) in separate frequency bands.

[0105] 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.

[0106] 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 regarding the locations of RUs to which multiple users (i.e., multiple receiving STAs) are allocated.

[0107] 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 a single STA. Resources may be allocated in RU units for the non-legacy STF, non-legacy LTF, and Data field.

[0108] 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.

[0109] 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 or may not be contiguous in the frequency domain.

[0110] The specific size of an RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is illustrative and not restrictive. 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 size of the RU.

[0111] 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, examples of the present disclosure may be applied to a new PPDU format in which some fields are excluded and / or some fields are added based on the PPDU format of Fig. 7, in addition to the PPDU format illustrated in Fig. 7.

[0112] Resource Units

[0113] 8 to 10 are diagrams illustrating examples of resource units in a wireless LAN system to which the present disclosure can be applied.

[0114] 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.

[0115] 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.

[0116] FIG. 8 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on a 20 MHz band.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] FIG. 9 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on a 40 MHz band.

[0121] 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.

[0122] Also, as shown in the figure, when used for a single user, 484-RU may be used.

[0123] FIG. 10 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on an 80 MHz band.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.). In other words, 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.

[0128] 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 can use an RU placement that excludes 996-tone RUs.

[0129] 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.

[0130] 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 through the first RU within one MU PPDU, and the X-STF, X-LTF, and Data fields for the second STA through the second RU. Information regarding the location of the RUs may be signaled through the X-SIG (e.g., X is HE, EHT, U) field in the X-PPDU format.

[0131] Distributed Resource Units

[0132] Regulations in various regions may impose limitations on power spectral density (PSD) in sub-7 GHz (e.g., 6 GHz) bands. For non-AP STAs in low power indoor (LPI) bands, the PSD limit may be -1 dBm / MHz. For example, for an existing 52-tone RU, the maximum transmit (Tx) power may be approximately 6 dBm.

[0133] Also, separate limits may apply in the 2.4 GHz and 5 GHz bands. For example, in the EU / China / Japan / Korea, a PSD limit of 10 dBm / MHz may apply in the 2.4 GHz band. This means that for an existing 52-tone RU, the maximum Tx power would be approximately 17 dBm. If the PSD limit in the 5 GHz band can be avoided, the transmit power can be increased. For example, for an existing 52-tone RU, the maximum transmit power is 24 dBm, which is still 6 dBm lower than the maximum allowed EIRP (effective isotropic radiated power) of 30 dBm.

[0134] Overcoming the PSD limitation allows for increased transmit power, which can enhance spectral efficiency or extend range.

[0135] Considering that the PSD limit is defined per MHz for each STA, distributing the tones of small-sized RUs over a wide bandwidth makes the tones for each STA non-contiguous, and therefore each tone can be transmitted at high power. RUs that include such distributed tones are referred to as distributed RUs (DRUs). To distinguish them from RUs that include continuous tones defined in existing WLAN systems (e.g., systems conforming to IEEE 802.11ax, 11be, etc.), they can be referred to as regular RUs (RRUs).

[0136] Compared to STAs transmitting with existing RRUs, STAs transmitting with DRUs can use higher power. For example, a 52-tone DRU over 80 MHz has only one tone per MHz, whereas for a 52-tone RRU, there are approximately 13 tones per MHz. Assuming a PSD limit of -1 dBm / MHz in the 6 GHz LPI band, the transmit power can be increased by approximately 11 dB when using a DRU over a 52-tone RU. This increased transmit power allows for a higher MCS and supports longer ranges.

[0137] FIG. 11 is a diagram illustrating an example of a DRU to which the present disclosure can be applied.

[0138] In the example of Figure 11, STA1 transmits on DRU1, STA2 transmits on DRU2, and STA3 transmits on DRU3. Each STA can apply a transmit power boost by using the DRU. Compared to using an RRU of the same size, the DRU applies higher transmit power to all tones, which can significantly improve spectral efficiency. In this way, the DRU can be particularly useful in UL-OFDMA.

[0139] The DRU can also be utilized in the AP. In some cases, the AP can perform DL-OFDMA transmission to the STA using only a part of DRU1, DRU2, and DRU3, in which case the transmit power boost by using the DRU can be applied.

[0140] To maximize the power boost, the tones within one DRU may be spread as far apart as possible, for example, a DRU containing one tone per MHz may be considered an optimal example. The size of the DRU (or the number of available tones included in one DRU (i.e., the number of remaining tones excluding unusable tones such as null tones, guard tones, and DC tones)) may be defined to be the same as the size of the RRU (or the number of available tones included in one RRU). This minimizes the impact on various technologies already defined based on the RRU. The table below shows examples of achievable power boost (in dB) for various DRUs distributed over different bandwidths. The example in the table below assumes the 6 GHz LPI band, but power boost can also be obtained in the 2.4 GHz and 5 GHz bands in other regions. For example, in an 80 MHz UL-OFDMA transmission with eight users, when each user uses a 106-tone DRU, the overall performance can be improved by approximately 8.13 dB compared to when each user uses a 106-tone RRU. In this way, using a DRU can overcome PSD limitations and achieve significant gains.

[0141] [Table 1]

[0142] Trigger Frame

[0143] FIG. 12 is a diagram illustrating an exemplary format of a trigger frame to which the present disclosure can be applied.

[0144] The trigger frame may allocate resources for one or more TB PPDU transmissions and request TB PPDU transmissions. The trigger frame may further include other information required by the STA transmitting the TB PPDU in response. The trigger frame may include common information and a user information list field in the frame body.

[0145] The common information field may include information commonly applied to one or more TB PPDU transmissions requested by the trigger frame, such as a trigger type, a UL length, whether or not a subsequent trigger frame exists (e.g., More TF), whether or not a channel sensing (CS) request is required, a UL BW (bandwidth), etc. Figure 12 illustrates an example of an EHT variant common information field format.

[0146] The 4-bit Trigger Type subfield may have values ​​from 0 to 15. Among these, the values ​​0, 1, 2, 3, 4, 5, 6, and 7 of the Trigger Type subfield are defined as corresponding to basic, Beamforming Report Poll (BFRP), multi user-block acknowledgement request (MU-BAR), multi user-request to send (MU-RTS), Buffer Status Report Poll (BSRP), groupcast with retries (GCR) MU-BAR, Bandwidth Query Report Poll (BQRP), and NDP Feedback Report Poll (NFRP), respectively, and the values ​​8 to 15 are defined as reserved.

[0147] The trigger dependent common info subfield of the common information may include information that is selectively included based on the trigger type.

[0148] A special user info field may be included in the trigger frame. The special user info field does not include user-specific information, but includes extended common information not provided in the common information field.

[0149] The user info list contains zero or more user info fields. Figure 12 illustrates an example of an EHT variant user info field format.

[0150] The AID12 subfield basically indicates that it is a user information field for the STA having the corresponding AID. In addition, if the AID12 field has a predetermined specific value, it may be used for other purposes, such as allocating a random access (RA)-RU or being configured as a special user information field. The special user information field does not include user-specific information, but is a user information field that includes extended common information that is not provided in the common information field. For example, the special user information field may be identified by an AID12 value of 2007, and a special user information field flag subfield in the common information field may indicate whether the special user information field is included.

[0151] The RU allocation subfield can indicate the size and location of the RU / MRU. For this purpose, the RU allocation subfield may be parsed together with the PS160 (primary / secondary 160 MHz) subfield of the user information field, the UL BW subfield of the common information field, etc.

[0152] For example, the mapping of the RU allocation subfields B7-B1 together with the settings of the RU allocation subfield B0 and the PS160 subfield may be defined as shown in Table 2 below. Table 2 shows an example of encoding of the PS160 subfield and the RU allocation subfield of the EHT variant user information field.

[0153] [Table 2]

[0154] JPEG2026507834000004.jpg122112

[0155] JPEG2026507834000005.jpg79108

[0156] When B0 of the RU Allocation subfield is set to 0, it indicates that the RU / MRU allocation applies to the primary 80 MHz channel, and when it is set to a value of 1, it can indicate that the RU allocation applies to the secondary 80 MHz channel of the primary 160 MHz. When B0 of the RU Allocation subfield is set to 0, it can indicate that the RU / MRU allocation applies to the lower 80 MHz of the secondary 160 MHz, and when it is set to a value of 1, it can indicate that the RU allocation applies to the upper 80 MHz of the secondary 160 MHz.

[0157] In the trigger frame RU allocation table of Table 2, the parameter N may be calculated based on the formula N=2*X1+X0. For bandwidths below 80 MHz, the PS160, B0, X0, and X1 values ​​may be set to 0. For bandwidths of 160 MHz and 320 MHz, the PS160, B0, X0, and X1 values ​​may be set as shown in Table 3. This setting indicates the absolute frequency order for the primary and secondary 80 MHz and 160 MHz channels. The order from left to right represents the order from lowest frequency to highest frequency. The primary 80 MHz channel is denoted as P80, the secondary 80 MHz channel is denoted as S80, and the secondary 160 MHz channel is denoted as S160.

[0158] [Table 3]

[0159] DRU tone plan based transmission and reception

[0160] As mentioned above, to overcome the PSD limitation and improve the power gain, a DRU using distributed tones / subcarriers may be applied instead of an RRU using continuous tones / subcarriers.

[0161] In this disclosure, definitions of DRU tone plans of various sizes and transmission / reception methods based thereon are described for DRU-based transmission / reception using PPDUs in a bandwidth including a 40 MHz channel.

[0162] Tone plans for a 40 MHz bandwidth may include examples supporting existing RRUs of various sizes (e.g., FIG. 9) and examples for DRUs of various sizes according to the present disclosure. In tone plans for DRU applications, the number of tones / subcarriers included in each DRU (i.e., DRU size) is the same as the number of tones / subcarriers included in the corresponding RRU (i.e., RRU size), but the locations of each tone / subcarrier in the frequency domain may be defined to be different from each other. For example, tone plans supporting 26-tone DRUs, 52-tone DRUs, 106-tone DRUs, and 242-tone DRUs may be defined for a 40 MHz bandwidth, but a 484-tone DRU is not included in the examples of the present disclosure because it cannot support tone / subcarrier distribution.

[0163] In the examples of the present disclosure, it is assumed that the number and positions of DC subcarriers, null subcarriers, and guard subcarriers in the DRU tone plan for a 40 MHz bandwidth are the same as those in the RRU tone plan for a 40 MHz bandwidth, i.e., of the 512 subcarriers in the 40 MHz bandwidth, the DC subcarriers may correspond to the 5 subcarriers in the middle of the 40 MHz bandwidth, and the guard subcarriers may correspond to the 12 subcarriers on the leftmost side and the 11 subcarriers on the rightmost side of the 40 MHz bandwidth. There are 16 null subcarriers (subcarrier indexes -244, -191, -190, -137, -110, -57, -56, -3, 3, 56, 57, 110, 137, 190, 191, 244) for the 26-tone DRU and 52-tone DRU, and 8 null subcarriers (subcarrier indexes -244, -137, -110, -3, 3, 110, 137, 244) for the 106-tone DRU (i.e., 8 null subcarrier positions out of the 16 considered in the 26-tone DRU and 52-tone DRU are used as available subcarriers in the 106-tone DRU), and no null subcarriers apply to the 242-tone DRU (i.e., 8 null subcarrier positions considered in the 106-tone DRU are used as available subcarriers in the 242-tone DRU). In the following description, the remaining subcarriers within the bandwidth, excluding the DC subcarrier, the null subcarrier, and the guard subcarriers, can be referred to as available subcarriers.

[0164] In the embodiments described below, the DRU index (i.e., DRU-n) or the nth DRU may correspond to a position in the frequency domain, or may be assigned regardless of its position in the frequency domain. For clarity, in the embodiments described below, a relatively low DRU index is described as including a relatively low tone / subcarrier, but the scope of the present disclosure is not limited thereto, and the DRU index may be assigned in various manners to distinguish different DRUs from each other.

[0165] Also, in the following description, subcarrier indices are assumed to correspond to positions in the frequency domain, with the index of the DC subcarrier assumed to be 0, and the term subcarrier may be replaced with tone.

[0166] In the following description, the expression a:b:c for subcarrier indices means every b subcarrier indices from a to c. In the following description, +-{a:b:c} means {-a:b:-c,a:b:c}. In the following description, +-{a,b,c} means {-a,-b,-c,a,b,c}.

[0167] Example 1

[0168] In this embodiment, various examples of subcarrier indexes that make up a 26-tone DRU will be described.

[0169] Example 1-1

[0170] This embodiment relates to a scheme in which one subcarrier is allocated to each of the 18 26-tone DRUs in order from the lowest available subcarrier to the highest available subcarrier. For example, each of the 18 26-tone DRUs may include the following subcarriers:

[0171] 26-tone DRU-1: -243, -225, -207, -187, -169, -151, -132, -114, -95, -77, -59, -39, -21, 4, 22, 40, 60, 78, 96, 115, 133, 152, 170, 188, 208, 226

[0172] 26-tone DRU-2: -242, -224, -206, -186, -168, -150, -131, -113, -94, -76, -58, -38, -20, 5, 23, 41, 61, 79, 97, 116, 134, 153, 171, 189, 209, 227

[0173] 26-tone DRU-3: -241, -223, -205, -185, -167, -149, -130, -112, -93, -75, -55, -37, -19, 6, 24, 42, 62, 80, 98, 117, 135, 154, 172, 192, 210, 228

[0174] 26-tone DRU-4: -240, -222, -204, -184, -166, -148, -129, -111, -92, -74, -54, -36, -18, 7, 25, 43, 63, 81, 99, 118, 136, 155, 173, 193, 211, 229

[0175] 26-tone DRU-5: -239, -221, -203, -183, -165, -147, -128, -109, -91, -73, -53, -35, -17, 8, 26, 44, 64, 82, 100, 119, 138, 156, 174, 194, 212, 230

[0176] 26-tone DRU-6: -238, -220, -202, -182, -164, -146, -127, -108, -90, -72, -52, -34, -16, 9, 27, 45, 65, 83, 101, 120, 139, 157, 175, 195, 213, 231

[0177] 26-tone DRU-7: -237, -219, -201, -181, -163, -145, -126, -107, -89, -71, -51, -33, -15, 10, 28, 46, 66, 84, 102, 121, 140, 158, 176, 196, 214, 232

[0178] 26-tone DRU-8: -236, -218, -200, -180, -162, -144, -125, -106, -88, -70, -50, -32, -14, 11, 29, 47, 67, 85, 103, 122, 141, 159, 177, 197, 215, 233

[0179] 26-tone DRU-9: -235, -217, -199, -179, -161, -143, -124, -105, -87, -69, -49, -31, -13, 12, 30, 48, 68, 86, 104, 123, 142, 160, 178, 198, 216, 234

[0180] 26-tone DRU-10: -234, -216, -198, -178, -160, -142, -123, -104, -86, -68, -48, -30, -12, 13, 31, 49, 69, 87, 105, 124, 143, 161, 179, 199, 217, 235

[0181] 26-tone DRU-11: -233, -215, -197, -177, -159, -141, -122, -103, -85, -67, -47, -29, -11, 14, 32, 50, 70, 88, 106, 125, 144, 162, 180, 200, 218, 236

[0182] 26-tone DRU-12: -232, -214, -196, -176, -158, -140, -121, -102, -84, -66, -46, -28, -10, 15, 33, 51, 71, 89, 107, 126, 145, 163, 181, 201, 219, 237

[0183] 26-tone DRU-13: -231, -213, -195, -175, -157, -139, -120, -101, -83, -65, -45, -27, -9, 16, 34, 52, 72, 90, 108, 127, 146, 164, 182, 202, 220, 238

[0184] 26-tone DRU-14: -230, -212, -194, -174, -156, -138, -119, -100, -82, -64, -44, -26, -8, 17, 35, 53, 73, 91, 109, 128, 147, 165, 183, 203, 221, 239

[0185] 26-tone DRU-15: -229, -211, -193, -173, -155, -136, -118, -99, -81, -63, -43, -25, -7, 18, 36, 54, 74, 92, 111, 129, 148, 166, 184, 204, 222, 240

[0186] 26-tone DRU-16: -228, -210, -192, -172, -154, -135, -117, -98, -80, -62, -42, -24, -6, 19, 37, 55, 75, 93, 112, 130, 149, 167, 185, 205, 223, 241

[0187] 26-tone DRU-17: -227, -209, -189, -171, -153, -134, -116, -97, -79, -61, -41, -23, -5, 20, 38, 58, 76, 94, 113, 131, 150, 168, 186, 206, 224, 242

[0188] 26-tone DRU-18: -226, -208, -188, -170, -152, -133, -115, -96, -78, -60, -40, -22, -4, 21, 39, 59, 77, 95, 114, 132, 151, 169, 187, 207, 225, 243

[0189] Example 1-2

[0190] This embodiment relates to a scheme in which one subcarrier is allocated to each of 18 26-tone DRUs in order from the lowest available subcarrier to the highest available subcarrier below the DC subcarrier (i.e., subcarriers with negative indices), and subcarriers that are mirror symmetric with respect to the allocated subcarriers and the DC subcarrier (i.e., subcarriers with positive indices) are allocated to the 26-tone DRUs including the allocated subcarriers. For example, each of the 18 26-tone DRUs may include the following subcarriers:

[0191] 26 Tone DRU-1: +-{21, 39, 59, 77, 95, 114, 132, 151, 169, 187, 207, 225, 243}

[0192] 26-tone DRU-2: +-{20, 38, 58, 76, 94, 113, 131, 150, 168, 186, 206, 224, 242}

[0193] 26-tone DRU-3: +-{19, 37, 55, 75, 93, 112, 130, 149, 167, 185, 205, 223, 241}

[0194] 26 Tone DRU-4: +-{18,36,54,74,92,111,129,148,166,184,204,222,240}

[0195] 26 Tone DRU-5: +-{17,35,53,73,91,109,128,147,165,183,203,221,239}

[0196] 26 Tone DRU-6: +-{16,34,52,72,90,108,127,146,164,182,202,220,238}

[0197] 26 Tone DRU-7: +-{15,33,51,71,89,107,126,145,163,181,201,219,237}

[0198] 26 Tone DRU-8: +-{14,32,50,70,88,106,125,144,162,180,200,218,236}

[0199] 26 Tone DRU-9: +-{13,31,49,69,87,105,124,143,161,179,199,217,235}

[0200] 26 Tone DRU-10: +-{12,30,48,68,86,104,123,142,160,178,198,216,234}

[0201] 26 Tone DRU-11: +-{11, 29, 47, 67, 85, 103, 122, 141, 159, 177, 197, 215, 233}

[0202] 26-tone DRU-12: +-{10, 28, 46, 66, 84, 102, 121, 140, 158, 176, 196, 214, 232}

[0203] 26-tone DRU-13: +-{9,27,45,65,83,101,120,139,157,175,195,213,231}

[0204] 26-tone DRU-14: +-{8,26,44,64,82,100,119,138,156,174,194,212,230}

[0205] 26 Tone DRU-15: +-{7,25,43,63,81,99,118,136,155,173,193,211,229}

[0206] 26-tone DRU-16: +-{6,24,42,62,80,98,117,135,154,172,192,210,228}

[0207] 26 Tone DRU-17: +-{5,23,41,61,79,97,116,134,153,171,189,209,227}

[0208] 26 Tone DRU-18: +-{4,22,40,60,78,96,115,133,152,170,188,208,226}

[0209] In the above example, in Example 1-1, the spacing between subcarriers in each DRU is maintained constant compared to Example 1-2, making it easier to apply interpolation techniques, etc., and therefore may be advantageous in terms of channel estimation performance. Also, in Example 1-2, the subcarrier spacing is symmetrical with respect to DC compared to Example 1-1, so better performance can be expected depending on the application.

[0210] Subcarrier indices may be assigned to the 26-tone DRU in other manners in addition to the subcarrier indices included in the 26-tone DRU as illustrated in the examples of Examples 1-1 and 1-2 described above. For example, although the examples described above assume that the available subcarriers exclude the guard, null, and DC subcarriers, it is also possible to define the subcarrier indices included in each 26-tone DRU by assuming that the available subcarriers include one or more of the guard, null, or DC subcarriers.

[0211] Example 2

[0212] In this embodiment, various examples of subcarrier indexes that make up a 52-tone DRU are described.

[0213] For example, eight 52-tone DRUs may be defined within a 40 MHz bandwidth, and one 52-tone DRU may correspond to a combination of two 26-tone DRUs. For example, two 26-tone DRUs may correspond to two of the 18 26-tone DRUs defined in the first embodiment. If 26-tone DRU-5 and 26-tone DRU-14 are not used as the base for the 52-tone DRU, a combination of two 26-tone DRUs from the 16 26-tone DRUs may correspond to one 52-tone DRU.

[0214] The two 26-tone DRUs corresponding to one 52-tone DRU may correspond to those that are spaced as far apart as possible in the frequency domain and that allow subcarriers to be evenly distributed across the 52-tone DRU. The eight 52-tone DRUs may be defined as follows:

[0215] 52-tone DRU-1, 26-tone DRU-1, and 26-tone DRU-10

[0216] 52-tone DRU-2, 26-tone DRU-2, and 26-tone DRU-11

[0217] 52-tone DRU-3, 26-tone DRU-3, and 26-tone DRU-12

[0218] 52-tone DRU-4, 26-tone DRU-4, and 26-tone DRU-13

[0219] 52-tone DRU-5, 26-tone DRU-6, and 26-tone DRU-15

[0220] 52-tone DRU-6, 26-tone DRU-7, and 26-tone DRU-16

[0221] 52-tone DRU-7, 26-tone DRU-8, and 26-tone DRU-17

[0222] 52-tone DRU-8, 26-tone DRU-9, and 26-tone DRU-18

[0223] Here, each 52-tone DRU may be defined as a set of subcarrier indexes corresponding to the 26-tone DRU indexes defined in Example 1-1 or 1-2.

[0224] Example 3

[0225] In this embodiment, various examples of subcarrier indexes that make up a 106-tone DRU will be described.

[0226] For example, four 106-tone DRUs may be defined within a 40 MHz bandwidth. The subcarrier indexes included in one 106-tone DRU may correspond to a set of the subcarrier indexes included in two 52-tone DRUs and two additional subcarrier indexes. The subcarriers included in each 106-tone DRU may be defined to maximize dispersion.

[0227] Example 3-1

[0228] The two additional subcarriers included in the 106-tone DRU may be two of the 16 null subcarriers (e.g., +-{3, 56, 57, 110, 137, 190, 191, 244}) that are not used in the 26-tone DRU and 52-tone DRU. That is, some of the null subcarriers in the 26-tone DRU and 52-tone DRU may be included in the available subcarriers for the 106-tone DRU. Also, the two additional subcarrier indices included in different 106-tone DRUs may not overlap with each other.

[0229] For example, if a 26-tone DRU corresponding to a 52-tone DRU is defined according to Example 1-1, four 106-tone DRUs may be defined as follows:

[0230] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-5, and subcarrier index {-191,56}

[0231] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-6, and subcarrier index {-190,57}

[0232] 106-tone DRU-3: 52-tone DRU-3, 52-tone DRU-7, and subcarrier index {-57,190}

[0233] 106-tone DRU-4: 52-tone DRU-4, 52-tone DRU-8, and subcarrier index {-56,191}

[0234] Alternatively, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to Example 1-1, four 106-tone DRUs may be defined as follows:

[0235] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-5, and subcarrier index {-56,191}

[0236] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-6, and subcarrier index {-191,56}

[0237] 106-tone DRU-3: 52-tone DRU-3, 52-tone DRU-7, and subcarrier index {-190,57}

[0238] 106-tone DRU-4: 52-tone DRU-4, 52-tone DRU-8, and subcarrier index {-57,190}

[0239] Alternatively, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to Example 1-1, four 106-tone DRUs may be defined as follows:

[0240] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-5, and subcarrier index {-57,190}

[0241] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-6, and subcarrier index {-56,191}

[0242] 106-tone DRU-3: 52-tone DRU-3, 52-tone DRU-7, and subcarrier index {-191,56}

[0243] 106-tone DRU-4: 52-tone DRU-4, 52-tone DRU-8, and subcarrier index {-190,57}

[0244] Alternatively, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to Example 1-1, four 106-tone DRUs may be defined as follows:

[0245] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-5, and subcarrier index {-190,57}

[0246] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-6, and subcarrier index {-57,190}

[0247] 106-tone DRU-3: 52-tone DRU-3, 52-tone DRU-7, and subcarrier index {-56,191}

[0248] 106-tone DRU-4: 52-tone DRU-4, 52-tone DRU-8, and subcarrier index {-191,56}

[0249] Example 3-2

[0250] Similar to Example 3-1, the two additional subcarriers included in the 106-tone DRU may be two of the 16 null subcarriers (e.g., +-{3, 56, 57, 110, 137, 190, 191, 244}) unused in the 26-tone DRU and 52-tone DRU.

[0251] For example, if a 26-tone DRU corresponding to a 52-tone DRU is defined according to Example 1-2, four 106-tone DRUs may be defined as follows:

[0252] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-5, and subcarrier index {-191, 191}

[0253] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-6, and subcarrier index {-190, 190}

[0254] 106-tone DRU-3: 52-tone DRU-3, 52-tone DRU-7, and subcarrier index {-57,57}

[0255] 106-tone DRU-4: 52-tone DRU-4, 52-tone DRU-8, and subcarrier index {-56,56}

[0256] Alternatively, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to Example 1-2, four 106-tone DRUs may be defined as follows:

[0257] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-5, and subcarrier index {-56,56}

[0258] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-6, and subcarrier index {-191, 191}

[0259] 106-tone DRU-3: 52-tone DRU-3, 52-tone DRU-7, and subcarrier index {-190, 190}

[0260] 106-tone DRU-4: 52-tone DRU-4, 52-tone DRU-8, and subcarrier index {-57,57}

[0261] Alternatively, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to Example 1-2, four 106-tone DRUs may be defined as follows:

[0262] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-5, and subcarrier index {-57,57}

[0263] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-6, and subcarrier index {-56,56}

[0264] 106-tone DRU-3: 52-tone DRU-3, 52-tone DRU-7, and subcarrier index {-191, 191}

[0265] 106-tone DRU-4: 52-tone DRU-4, 52-tone DRU-8, and subcarrier index {-190, 190}

[0266] Alternatively, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to Example 1-2, four 106-tone DRUs may be defined as follows:

[0267] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-5, and subcarrier index {-190, 190}

[0268] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-6, and subcarrier index {-57,57}

[0269] 106-tone DRU-3: 52-tone DRU-3, 52-tone DRU-7, and subcarrier index {-56,56}

[0270] 106-tone DRU-4: 52-tone DRU-4, 52-tone DRU-8, and subcarrier index {-191, 191}

[0271] DRUs of the same / different sizes can be assigned to different STAs according to the DRU tone plans defined in the various examples of this disclosure above.

[0272] For example, when a specific RU index is indicated through an RU allocation field included in a SIG (e.g., U-SIG and / or UHR-SIG) field in DL OFDMA transmission, a STA receiving a PPDU can interpret the PPDU as a data field mapped to a subcarrier included in a DRU corresponding to the indicated RU index and decode the data field accordingly. Alternatively, when a specific RU index is indicated through an RU allocation subfield in a trigger frame, a STA receiving a trigger frame can transmit a TB PPDU in which the data field is mapped to a subcarrier included in a DRU corresponding to the indicated RU index. Here, the DRU corresponding to the indicated RU index may be determined based on a mapping rule between an RRU and a DRU.

[0273] Example 4

[0274] In this embodiment, various examples of subcarrier indexes that make up a 242-tone DRU will be described.

[0275] For example, two 242-tone DRUs may be defined within a 40 MHz bandwidth. The subcarrier indexes included in one 242-tone DRU may correspond to a set of subcarrier indexes included in two 106-tone DRUs, subcarrier indexes included in one 26-tone DRU, and four additional subcarrier indexes. One 26-tone DRU included in one 242-tone DRU may correspond to one of two 26-tone DRUs (i.e., 26-tone DRU-5 and 26-tone DRU-14) among the 18 26-tone DRUs that are not used in combinations of other larger-sized DRUs. Furthermore, the subcarriers included in each 242-tone DRU may be defined to maximize dispersion.

[0276] Example 4-1

[0277] The four additional subcarriers included in the 242-tone DRU may be four of the eight null subcarriers (e.g., + / -{3, 110, 137, 244}) that are not commonly used in the 26-tone DRU, 52-tone DRU, and 106-tone DRU. That is, some of the null subcarriers in the 26-tone DRU and 52-tone DRU, or some of the null subcarriers in the 106-tone DRU, may be included in the available subcarriers for the 242-tone DRU. Furthermore, the four additional subcarrier indexes included in different 242-tone DRUs may not overlap with each other.

[0278] For example, when a 26-tone DRU corresponding to a 106-tone DRU (or a 52-tone DRU corresponding to a 106-tone DRU) is defined according to Example 1-1, two 242-tone DRUs may be defined as follows:

[0279] 242-tone DRU-1: 106-tone DRU-1, 106-tone DRU-3, 26-tone DRU-5, and subcarrier index {-137, -3, 110, 244}

[0280] 242-tone DRU-2: 106-tone DRU-2, 106-tone DRU-4, 26-tone DRU-14, and subcarrier index {-244, -110, 3, 137}

[0281] Alternatively, when a 26-tone DRU corresponding to a 106-tone DRU (or a 52-tone DRU corresponding to a 106-tone DRU) is defined according to Example 1-1, two 242-tone DRUs may be defined as follows:

[0282] 242-tone DRU-1: 106-tone DRU-1, 106-tone DRU-3, 26-tone DRU-5, and subcarrier index {-244, -110, 3, 137}

[0283] 242-tone DRU-2: 106-tone DRU-2, 106-tone DRU-4, 26-tone DRU-14, and subcarrier index {-137, -3, 110, 244}

[0284] Example 4-2

[0285] Similar to Example 4-1, the four additional subcarriers included in the 242-tone DRU may be four of the eight null subcarriers (e.g., +-{3, 110, 137, 244}) unused in the 26-tone DRU, 52-tone DRU, and 106-tone DRU.

[0286] For example, when a 26-tone DRU corresponding to a 106-tone DRU (or a 52-tone DRU corresponding to a 106-tone DRU) is defined according to Example 1-2, two 242-tone DRUs may be defined as follows:

[0287] 242-tone DRU-1: 106-tone DRU-1, 106-tone DRU-3, 26-tone DRU-5, and subcarrier index {-137, -3, 3, 137}

[0288] 242-tone DRU-2: 106-tone DRU-2, 106-tone DRU-4, 26-tone DRU-14, and subcarrier index {-244, -110, 110, 244}

[0289] Alternatively, when a 26-tone DRU corresponding to a 106-tone DRU (or a 52-tone DRU corresponding to a 106-tone DRU) is defined according to Example 1-2, two 242-tone DRUs may be defined as follows:

[0290] 242-tone DRU-1: 106-tone DRU-1, 106-tone DRU-3, 26-tone DRU-5, and subcarrier index {-244, -110, 110, 244}

[0291] 242-tone DRU-2: 106-tone DRU-2, 106-tone DRU-4, 26-tone DRU-14, and subcarrier index {-137, -3, 3, 137}

[0292] Pilot Tone for DRU Tone Plan

[0293] This example relates to the pilot tones for each DRU for the DRU tone plan for the 20 MHz channel defined above.

[0294] For example, in a 26-tone DRU, two of the 26 tones may be defined as pilot tones. In a 52-tone DRU, four of the 52 tones may be defined as pilot tones. In a 106-tone DRU, four of the 106 tones may be defined as pilot tones. In a 242-tone DRU, eight of the 242 tones may be defined as pilot tones. The pilot sequence has a length corresponding to the number of pilot tones, each element of the pilot sequence may be 1 or -1, and the order of the elements in the pilot sequence may be determined based on the DRU index. Various examples for the positions of the pilot tones (i.e., subcarrier index) are described below.

[0295] FIG. 13 is a diagram for explaining an example of a DRU tone plan and a pilot tone-based PPDU reception method of a first STA according to the present disclosure.

[0296] In step S1310, the first STA may generate a PPDU including one or more fields to be mapped onto one or more DRUs.

[0297] For example, one or more of the fields may include a data field, i.e., the data field of the PPDU may be generated to map onto one or more DRUs of various sizes.

[0298] When one or more DRUs include one 26-tone DRU, the 26-tone DRU may be one of the 18 predefined 26-tone DRUs. For example, the pilot tones of each of the 18 predefined 26-tone DRUs may be the 7th lowest subcarrier and the 7th highest subcarrier among the subcarriers included in one 26-tone DRU.

[0299] When one or more DRUs include a 52-tone DRU, the 52-tone DRU may be any one of eight predefined 52-tone DRUs. For example, the pilot tones of each of the eight predefined 52-tone DRUs may be the 9th lowest subcarrier, the 18th lowest subcarrier, the 18th highest subcarrier, and the 9th highest subcarrier among the subcarriers included in one 52-tone DRU.

[0300] When one or more DRUs include a 106-tone DRU, the 106-tone DRU may be any one of four predefined 106-tone DRUs. For example, the pilot tones of each of the four predefined 106-tone DRUs may be the 18th lowest subcarrier, the 36th lowest subcarrier, the 36th highest subcarrier, and the 18th highest subcarrier among the subcarriers included in one 106-tone DRU.

[0301] When one or more DRUs include a 242-tone DRU, the 242-tone DRU may be any one of two already defined 242-tone DRUs. For example, the pilot tones of each of the two already defined 242-tone DRUs may be the 25th lowest subcarrier, the 49th lowest subcarrier, the 73rd lowest subcarrier, the 97th lowest subcarrier, the 97th highest subcarrier, the 73rd highest subcarrier, the 49th highest subcarrier, and the 25th highest subcarrier among the subcarriers included in one 242-tone DRU.

[0302] Here, the n-th (n=1, 2, ..., 18) 26-tone DRU may include the n-th lowest subcarrier among available subcarriers in a 40 MHz channel. Also, the n-th (n=1, 2, ..., 18) 26-tone DRU may include every 18th subcarrier, and one of these subcarriers may correspond to the n-th lowest subcarrier mentioned above.

[0303] For example, a first 26-tone DRU may include subcarrier indices: -243, -225, -207, -187, -169, -151, -132, -114, -95, -77, -59, -39, -21, 4, 22, 40, 60, 78, 96, 115, 133, 152, 170, 188, 208, and 226. A second 26-tone DRU may include subcarrier indices: -242, -224, -206, -186, -168, -150, -131, -113, -94, -76, -58, -38, -20, 5, 23, 41, 61, 79, 97, 116, 134, 153, 171, 189, 209, and 227. The third 26-tone DRU may include subcarrier indices −241, −223, −205, −185, −167, −149, −130, −112, −93, −75, −55, −37, −19, 6, 24, 42, 62, 80, 98, 117, 135, 154, 172, 192, 210, and 228. The fourth 26-tone DRU may include subcarrier indices −240, −222, −204, −184, −166, −148, −129, −111, −92, −74, −54, −36, −18, 7, 25, 43, 63, 81, 99, 118, 136, 155, 173, 193, 211, and 229. The fifth 26-tone DRU may include subcarrier indices −239, −221, −203, −183, −165, −147, −128, −109, −91, −73, −53, −35, −17, 8, 26, 44, 64, 82, 100, 119, 138, 156, 174, 194, 212, and 230. The sixth 26-tone DRU may include subcarrier indices −238, −220, −202, −182, −164, −146, −127, −108, −90, −72, −52, −34, −16, 9, 27, 45, 65, 83, 101, 120, 139, 157, 175, 195, 213, and 231. The seventh 26-tone DRU may include subcarrier indices -237, -219, -201, -181, -163, -145, -126, -107, -89, -71, -51, -33, -15, 10, 28, 46, 66, 84, 102, 121, 140, 158, 176, 196, 214, and 232.The eighth 26-tone DRU may include subcarrier indices −236, −218, −200, −180, −162, −144, −125, −106, −88, −70, −50, −32, −14, 11, 29, 47, 67, 85, 103, 122, 141, 159, 177, 197, 215, and 233. The ninth 26-tone DRU may include subcarrier indices −235, −217, −199, −179, −161, −143, −124, −105, −87, −69, −49, −31, −13, 12, 30, 48, 68, 86, 104, 123, 142, 160, 178, 198, 216, and 234. The tenth 26-tone DRU may include subcarrier indices −234, −216, −198, −178, −160, −142, −123, −104, −86, −68, −48, −30, −12, 13, 31, 49, 69, 87, 105, 124, 143, 161, 179, 199, 217, and 235. The eleventh 26-tone DRU may include subcarrier indices −233, −215, −197, −177, −159, −141, −122, −103, −85, −67, −47, −29, −11, 14, 32, 50, 70, 88, 106, 125, 144, 162, 180, 200, 218, and 236. The twelfth 26-tone DRU may include subcarrier indices −232, −214, −196, −176, −158, −140, −121, −102, −84, −66, −46, −28, −10, 15, 33, 51, 71, 89, 107, 126, 145, 163, 181, 201, 219, and 237. The thirteenth 26-tone DRU may include subcarrier indices −231, −213, −195, −175, −157, −139, −120, −101, −83, −65, −45, −27, −9, 16, 34, 52, 72, 90, 108, 127, 146, 164, 182, 202, 220, and 238. The fourteenth 26-tone DRU may include subcarrier indices -230, -212, -194, -174, -156, -138, -119, -100, -82, -64, -44, -26, -8, 17, 35, 53, 73, 91, 109, 128, 147, 165, 183, 203, 221, 239.The fifteenth 26-tone DRU may include subcarrier indices −229, −211, −193, −173, −155, −136, −118, −99, −81, −63, −43, −25, −7, 18, 36, 54, 74, 92, 111, 129, 148, 166, 184, 204, 222, and 240. The sixteenth 26-tone DRU may include subcarrier indices −228, −210, −192, −172, −154, −135, −117, −98, −80, −62, −42, −24, −6, 19, 37, 55, 75, 93, 112, 130, 149, 167, 185, 205, 223, and 241. The seventeenth 26-tone DRU may include subcarrier indices: -227, -209, -189, -171, -153, -134, -116, -97, -79, -61, -41, -23, -5, 20, 38, 58, 76, 94, 113, 131, 150, 168, 186, 206, 224, and 242. The eighteenth 26-tone DRU may include subcarrier indices: -226, -208, -188, -170, -152, -133, -115, -96, -78, -60, -40, -22, -4, 21, 39, 59, 77, 95, 114, 132, 151, 169, 187, 207, 225, and 243.

[0304] In this case, the pilot tones for the first 26-tone DRU may be -132, 115. The pilot tones for the second 26-tone DRU may be -131, 116. The pilot tones for the third 26-tone DRU may be -130, 117. The pilot tones for the fourth 26-tone DRU may be -129, 118. The pilot tones for the fifth 26-tone DRU may be -128, 119. The pilot tones for the sixth 26-tone DRU may be -127, 120. The pilot tones for the seventh 26-tone DRU may be -126, 121. The pilot tones for the eighth 26-tone DRU may be -125, 122. The pilot tones for the ninth 26-tone DRU may be -124, 123. The pilot tones for the tenth 26-tone DRU may be -123, 124. The pilot tones for the eleventh 26-tone DRU may be -122, 125. The pilot tones for the twelfth 26-tone DRU may be -121, 126. The pilot tones for the thirteenth 26-tone DRU may be -120, 127. The pilot tones for the fourteenth 26-tone DRU may be -119, 128. The pilot tones for the fifteenth 26-tone DRU may be -118, 129. The pilot tones for the sixteenth 26-tone DRU may be -117, 130. The pilot tones for the seventeenth 26-tone DRU may be -116, 131. The pilot tones for the eighteenth 26-tone DRU may be -115, 132.

[0305] For example, the first 52-tone DRU may include subcarriers included in the first 26-tone DRU and the tenth 26-tone DRU. The second 52-tone DRU may include subcarriers included in the second 26-tone DRU and the eleventh 26-tone DRU. The third 52-tone DRU may include subcarriers included in the third 26-tone DRU and the twelfth 26-tone DRU. The fourth 52-tone DRU may include subcarriers included in the fourth 26-tone DRU and the thirteenth 26-tone DRU. The fifth 52-tone DRU may include subcarriers included in the sixth 26-tone DRU and the fifteenth 26-tone DRU. The sixth 52-tone DRU may include subcarriers included in the seventh 26-tone DRU and the sixteenth 26-tone DRU. The seventh 52-tone DRU may include subcarriers included in the eighth 26-tone DRU and the seventeenth 26-tone DRU. The eighth 52-tone DRU may include subcarriers included in the ninth 26-tone DRU and the eighteenth 26-tone DRU.

[0306] In this case, the pilot tones for the first 52-tone DRU may be -169, -86, 78, 161. The pilot tones for the second 52-tone DRU may be -168, -85, 79, 162. The pilot tones for the third 52-tone DRU may be -167, -84, 80, 163. The pilot tones for the fourth 52-tone DRU may be -166, -83, 81, 164. The pilot tones for the fifth 52-tone DRU may be -164, -81, 83, 166. The pilot tones for the sixth 52-tone DRU may be -163, -80, 84, 167. The pilot tones for the seventh 52-tone DRU may be -162, -79, 85, 168. The pilot tones for the eighth 52-tone DRU may be -161, -78, 86, 169.

[0307] For example, the first 106-tone DRU may include a first group corresponding to the subcarriers included in the first 52-tone DRU and the third 52-tone DRU, and two of the 16 null subcarriers. The second 106-tone DRU may include a second group corresponding to the subcarriers included in the second 52-tone DRU and the fourth 52-tone DRU, and two of the 16 null subcarriers. The third 106-tone DRU may include a third group corresponding to the subcarriers included in the third 52-tone DRU and the seventh 52-tone DRU, and two of the 16 null subcarriers. The fourth 106-tone DRU may include a fourth group corresponding to the subcarriers included in the fourth 52-tone DRU and the eighth 52-tone DRU, and two of the 16 null subcarriers.

[0308] Here, if the indices of the 16 null subcarriers are -244, -191, -190, -137, -110, -57, -56, -3, 3, 56, 57, 110, 137, 190, 191, 244, one of the first, second, third, and fourth groups of null subcarriers may include subcarrier indexes -191, 56, another may include subcarrier indexes -190, 57, another may include subcarrier indexes -57, 190, and the remaining one may include subcarrier indexes -56, 191.

[0309] In this case, the first pilot tone for the first 106-tone DRU may be either -169 or -164, the second pilot tone may be either -86 or -81, the third pilot tone may be either 78 or 83, and the fourth pilot tone may be either 161 or 166 (i.e., -169 / -164, -86 / -81, 78 / 83, 161 / 166). The first pilot tone for the second 106-tone DRU may be either -168 or -16, the second pilot tone may be either -85 or -80, the third pilot tone may be either 79 or 84, and the fourth pilot tone may be either 162 or 167 (i.e., -168 / -163, -85 / -80, 79 / 84, 162 / 167). Of the pilot tones for the third 106-tone DRU, the first pilot tone can be either -162 or -167, the second pilot tone can be either -79 or -84, the third pilot tone can be either 85 or 80, and the fourth pilot tone can be either 168 or 163 (i.e., -162 / -167, -79 / -84, 85 / 80, 168 / 163). Of the pilot tones for the fourth 106-tone DRU, the first pilot tone can be either -161 or -166, the second pilot tone can be either -78 or -83, the third pilot tone can be either 86 or 81, and the fourth pilot tone can be either 169 or 164 (i.e., -161 / -166, -78 / -83, 86 / 81, 169 / 164).

[0310] For example, the first 242-tone DRU may include a fifth group corresponding to the subcarriers included in the first 106-tone DRU, the third 106-tone DRU, and the fifth 26-tone DRU, and four of the eight null subcarriers. The second 242-tone DRU may include a sixth group corresponding to the subcarriers included in the second 106-tone DRU, the fourth 106-tone DRU, and the fourteenth 26-tone DRU, and the other four of the 16 null subcarriers.

[0311] Here, if the indexes of the eight null subcarriers are −244, −137, −110, −3, 3, 110, 137, and 244, one of the fifth and sixth groups of null subcarriers may include subcarrier indexes −137, −3, 110, and 244, and the other may include subcarrier indexes −244, −110, 3, and 137.

[0312] In this case, of the eight pilot tones for the first 242-tone DRU, the first pilot tone can be either -196 or -198, the second pilot tone can be either -147 or -149, the third pilot tone can be either -99 or -102, the fourth pilot tone can be either -52 or -53, the fifth pilot tone can be either 51 or 49, the sixth pilot tone can be either 100 or 98, the seventh pilot tone can be either 148 or 145, and the eighth pilot tone can be either 195 or 194 (i.e., -196 / -198, -147 / -149, -99 / -102, -52 / -53, 51 / 49, 100 / 98, 148 / 145, 195 / 194). Of the eight pilot tones for the second 242-tone DRU, the first pilot tone can be either -195 or -194, the second pilot tone can be either -148 or -145, the third pilot tone can be either -100 or -98, the fourth pilot tone can be either -51 or -49, the fifth pilot tone can be either 52 or 53, the sixth pilot tone can be either 99 or 102, the seventh pilot tone can be either 147 or 149, and the eighth pilot tone can be either 196 or 198 (i.e., -195 / -194, -148 / -145, -100 / -98, -51 / -49, 52 / 53, 99 / 102, 147 / 149, 196 / 198).

[0313] The above DRU tone plan and pilot tones are exemplary, and the tones / subcarriers and pilot tones / subcarriers included in a 26-tone DRU, a 52-tone DRU, a 106-tone DRU, and a 242-tone DRU may be defined using various other examples described below.

[0314] In step S1320, the first STA may transmit a PPDU to one or more second STAs on a bandwidth including the 40 MHz channel.

[0315] The one or more DRUs may be indicated based on RU allocation information included in the PPDU, which may be, for example, a downlink PPDU (or DL-OFDMA PPDU).

[0316] Alternatively, one or more DRUs may be designated based on RU allocation information included in a trigger frame that triggers the transmission of the PPDU. For example, the PPDU may be a TB PPDU (or an UL-OFDMA PPDU).

[0317] The method described in the example of Figure 13 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 generate a PPDU including one or more fields mapped onto one or more DRUs and transmit the PPDU to one or more second STAs over a bandwidth including a 40 MHz channel. Additionally, the one or more memories 104 of the first device 100 may store instructions for performing the method described in the example of Figure 13 or in the examples described below when executed by the one or more processors 102.

[0318] FIG. 14 is a diagram illustrating an example of a DRU tone plan and a pilot tone-based PPDU transmission method of a second STA according to the present disclosure.

[0319] In step S1410, the second STA may receive a PPDU including one or more fields from the first STA on a bandwidth including a 40 MHz channel.

[0320] In step S1420, the second STA may decode one or more fields mapped onto one or more DRUs.

[0321] For example, the second STA can determine the number and positions of tones / subcarriers and pilot tones / subcarriers of one or more DRUs to which one or more fields (e.g., data fields) in the PPDU transmitted by the first STA are mapped, based on the RU allocation information included in the PPDU or based on the RU allocation information included in the trigger frame that triggers the transmission of the PPDU. Based on this, the second STA can decode the one or more fields mapped to the one or more DRUs.

[0322] The various sizes (or number of tones / subcarriers) and locations of one or more DRUs are the same as those described in the example of FIG. 13, and a repeated description thereof will be omitted.

[0323] The method described in the example of Figure 14 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 a PPDU including one or more fields from the first STA over a bandwidth including a 40 MHz channel and decode the one or more fields mapped onto one or more DRUs. Additionally, the one or more memories 204 of the second device 200 may store instructions for performing the method described in the example of Figure 14 or in the examples described below when executed by the one or more processors 202.

[0324] 13 and 14 may correspond to some of various examples of the present disclosure. Various examples of the present disclosure, including the examples of Fig. 13 and 14, will be described in more detail below.

[0325] Example 5

[0326] This example relates to the location of pilot tones in DRUs of various sizes for 40 MHz transmission.

[0327] The various examples of pilot positions described below may be applied to the 26-tone DRUs based on Examples 1-1 and 1-2 above, and to DRUs of higher sizes based thereon. For example, Example 5-1 may correspond to a scheme in which pilot tones are uniformly distributed within a DRU of each size. Example 5-2 may correspond to a scheme in which pilot tones are uniformly distributed among even-indexed tones within a DRU of each size. Example 5-3 may correspond to a scheme in which pilot tones are uniformly distributed within a 26-tone DRU, and a DRU of higher size includes the positions of pilot tones within the 26-tone DRU. Example 5-4 may correspond to a scheme in which pilot tones are uniformly distributed among even-indexed tones within a 26-tone DRU, and a DRU of higher size includes the positions of pilot tones within the 26-tone DRU.

[0328] In the following description, when expressing subcarrier indices indicating pilot tone positions, a / b / c represents a, b, or c. {a / b,c} represents {a,c} or {b,c}. {a / b,c / d} represents {a,c} or {a,d} or {b,c} or {b,d}. {a / b,c,d / e} represents {a,c,d} or {a,c,e} or {b,c,d} or {b,c,e}. +-{a,b} represents {a,b} and {-a,-b}. +-a / b represents {a,-a} or {b,-b}.

[0329] Example 1-1 Base pilot tone position

[0330] Example 1-1 relates to a scheme in which one subcarrier is allocated to each of the eighteen 26-tone DRUs in order from the lowest available subcarrier to the highest available subcarrier. An example of pilot tone positions according to a scheme (Example 5-1) in which pilot tones are uniformly distributed for each of the 26-tone DRUs of Example 1-1 and DRUs of higher sizes based thereon is as follows:

[0331] 26-tone DRU-1:-132, 115

[0332] 26-tone DRU-2:-131, 116

[0333] 26-tone DRU-3: -130, 117

[0334] 26-tone DRU-4: -129, 118

[0335] 26-tone DRU-5: -128, 119

[0336] 26-tone DRU-6: -127, 120

[0337] 26-tone DRU-7:-126, 121

[0338] 26-tone DRU-8: -125, 122

[0339] 26-tone DRU-9:-124, 123

[0340] 26-tone DRU-10:-123, 124

[0341] 26-tone DRU-11:-122, 125

[0342] 26-tone DRU-12:-121, 126

[0343] 26-tone DRU-13:-120, 127

[0344] 26-tone DRU-14:-119, 128

[0345] 26-tone DRU-15:-118, 129

[0346] 26-tone DRU-16:-117, 130

[0347] 26-tone DRU-17:-116, 131

[0348] 26-tone DRU-18:-115, 132

[0349] 52-tone DRU-1: -169, -86, 78, 161

[0350] 52-tone DRU-2: -168, -85, 79, 162

[0351] 52-tone DRU-3: -167, -84, 80, 163

[0352] 52-tone DRU-4: -166, -83, 81, 164

[0353] 52-tone DRU-5: -164, -81, 83, 166

[0354] 52-tone DRU-6: -163, -80, 84, 167

[0355] 52-tone DRU-7: -162, -79, 85, 168

[0356] 52-tone DRU-8: -161, -78, 86, 169

[0357] 106-tone DRU-1: -169 / -164, -86 / -81, 78 / 83, 161 / 166

[0358] 106-tone DRU-2: -168 / -163, -85 / -80, 79 / 84, 162 / 167

[0359] 106-tone DRU-3: -162 / -167, -79 / -84, 85 / 80, 168 / 163

[0360] 106-tone DRU-4: -161 / -166, -78 / -83, 86 / 81, 169 / 164

[0361] 242-tone DRU-1: -196 / -198, -147 / -149, -99 / -102, -52 / -53, 51 / 49, 100 / 98, 148 / 145, 195 / 194

[0362] 242-tone DRU-2: -195 / -194, -148 / -145, -100 / -98, -51 / -49, 52 / 53, 99 / 102, 147 / 149, 196 / 198

[0363] For the 26-tone DRU of Example 1-1 and a DRU of a larger size based thereon, examples of pilot tone positions according to a scheme (Example 5-2) in which pilot tones are uniformly distributed among tones with even indexes are as follows.

[0364] 26-tone DRU-1: -132, 96

[0365] 26-tone DRU-2: -150, 116

[0366] 26-tone DRU-3: -130, 98

[0367] 26-tone DRU-4: -148, 118

[0368] 26-tone DRU-5: -128, 100 / 138

[0369] 26-tone DRU-6: -146 / -108, 120

[0370] 26-tone DRU-7:-126, 102 / 140

[0371] 26-tone DRU-8: -144 / -106, 122

[0372] 26-tone DRU-9:-124, 104 / 142

[0373] 26-tone DRU-10: -142 / -104, 124

[0374] 26-tone DRU-11:-122, 106 / 144

[0375] 26-tone DRU-12: -140 / -102, 126

[0376] 26-tone DRU-13:-120, 108 / 146

[0377] 26-tone DRU-14: -138 / -100, 128

[0378] 26-tone DRU-15:-118, 148

[0379] 26-tone DRU-16:-98, 130

[0380] 26-tone DRU-17:-116, 150

[0381] 26-tone DRU-18:-96, 132

[0382] 52-tone DRU-1: -178 / -160, -86, 78, 152 / 170

[0383] 52-tone DRU-2: -168, -94 / -76, 70 / 88, 162

[0384] 52-tone DRU-3: -176 / -158, -84, 80, 154 / 172

[0385] 52-tone DRU-4: -166, -92 / -74, 72 / 90, 164

[0386] 52-tone DRU-5: -164, -90 / -72, 74 / 92, 166

[0387] 52-tone DRU-6: -172 / -154, -80, 84, 158 / 176

[0388] 52-tone DRU-7: -162, -88 / -70, 76 / 94, 168

[0389] 52-tone DRU-8: -170 / -152, -78, 86, 160 / 178

[0390] 106 Tone DRU-1: -164, -86, 78, 166

[0391] 106 Tone DRU-2: -168, -80, 84, 162

[0392] 106 Tone DRU-3: -162, -84, 80, 168

[0393] 106 Tone DRU-4: -166, -78, 86, 164

[0394] 242 Tone DRU-1: -196 / -198, -146, -102, -52, 54 / 44, 100 / 98, 148, 194

[0395] 242-tone DRU-2: -194, -148, -100 / -98, -54 / -44, 52, 102, 146, 196 / 198

[0396] An example of pilot tone positions according to a scheme (embodiment 5-3) in which pilot tones are uniformly distributed for the 26-tone DRU in embodiment 1-1 and the larger size DRU includes pilot tone positions within the 26-tone DRU is as follows.

[0397] 26-tone DRU-1:-132, 115

[0398] 26-tone DRU-2:-131, 116

[0399] 26-tone DRU-3: -130, 117

[0400] 26-tone DRU-4: -129, 118

[0401] 26-tone DRU-5: -128, 119

[0402] 26-tone DRU-6: -127, 120

[0403] 26-tone DRU-7:-126, 121

[0404] 26-tone DRU-8: -125, 122

[0405] 26-tone DRU-9:-124, 123

[0406] 26-tone DRU-10:-123, 124

[0407] 26-tone DRU-11:-122, 125

[0408] 26-tone DRU-12:-121, 126

[0409] 26-tone DRU-13:-120, 127

[0410] 26-tone DRU-14:-119, 128

[0411] 26-tone DRU-15:-118, 129

[0412] 26-tone DRU-16:-117, 130

[0413] 26-tone DRU-17:-116, 131

[0414] 26-tone DRU-18:-115, 132

[0415] 52-tone DRU-1: -132, -123, 115, 124

[0416] 52-tone DRU-2: -131, -122, 116, 125

[0417] 52-tone DRU-3: -130, -121, 117, 126

[0418] 52-tone DRU-4: -129, -120, 118, 127

[0419] 52-tone DRU-5: -127, -118, 120, 129

[0420] 52-tone DRU-6: -126, -117, 121, 130

[0421] 52-tone DRU-7: -125, -116, 122, 131

[0422] 52-tone DRU-8: -124, -115, 123, 132

[0423] 106 Tone DRU-1: -132 / -127, -123 / -118, 115 / 120, 124 / 129

[0424] 106-tone DRU-2: -131 / -126, -122 / -117, 116 / 121, 125 / 130

[0425] 106-tone DRU-3: -130 / -125, -121 / -116, 117 / 122, 126 / 131

[0426] 106-tone DRU-4: -129 / -124, -120 / -115, 118 / 123, 127 / 132

[0427] 242-tone DRU-1: -132 / -127, -130 / -125, -123 / -118, -121 / -116, 115 / 120, 117 / 122, 124 / 129, 126 / 131

[0428] 242-tone DRU-2: -131 / -126, -129 / -124, -122 / -117, -120 / -115, 116 / 121, 118 / 123, 125 / 130, 127 / 132

[0429] For the 26-tone DRU in Example 1-1, pilot tones are uniformly distributed among even-indexed tones, and the higher-sized DRU includes the positions of pilot tones within the 26-tone DRU. An example of pilot tone positions according to this scheme (Example 5-4) is as follows:

[0430] 26-tone DRU-1: -132, 96

[0431] 26-tone DRU-2: -150, 116

[0432] 26-tone DRU-3: -130, 98

[0433] 26-tone DRU-4: -148, 118

[0434] 26-tone DRU-5: -128, 100 / 138

[0435] 26-tone DRU-6: -146 / -108, 120

[0436] 26-tone DRU-7:-126, 102 / 140

[0437] 26-tone DRU-8: -144 / -106, 122

[0438] 26-tone DRU-9:-124, 104 / 142

[0439] 26-tone DRU-10: -142 / -104, 124

[0440] 26-tone DRU-11:-122, 106 / 144

[0441] 26-tone DRU-12: -140 / -102, 126

[0442] 26-tone DRU-13:-120, 108 / 146

[0443] 26-tone DRU-14: -138 / -100, 128

[0444] 26-tone DRU-15:-118, 148

[0445] 26-tone DRU-16:-98, 130

[0446] 26-tone DRU-17:-116, 150

[0447] 26-tone DRU-18:-96, 132

[0448] 52-tone DRU-1: -132, -142 / -104, 96, 124

[0449] 52-tone DRU-2: -150, -122, 116, 106 / 144

[0450] 52-tone DRU-3: -130, -140 / -102, 98, 126

[0451] 52-tone DRU-4: -148, -120, 118, 108 / 146

[0452] 52-tone DRU-5: -146 / -108, -118, 120, 148

[0453] 52-tone DRU-6: -126, -98, 102 / 140, 130

[0454] 52-tone DRU-7: -144 / -106, -116, 122, 150

[0455] 52-tone DRU-8: -124, -96, 104 / 142, 132

[0456] 106-tone DRU-1: -132 / -146 / -108, -142 / -104 / -118, 96 / 120, 124 / 148

[0457] 106-tone DRU-2: -150 / -126, -122 / -98, 116 / 102 / 140, 106 / 144 / 130

[0458] 106-tone DRU-3: -130 / -144 / -106, -140 / -102 / -116, 98 / 122, 126 / 150

[0459] 106-tone DRU-4: -148 / -124, -120 / -96, 118 / 104 / 142, 108 / 146 / 132

[0460] 242-tone DRU-1: -132 / -146 / -108, -130 / -144 / -106, -142 / -104 / -118, -140 / -102 / -116, 96 / 120, 98 / 122, 124 / 148, 126 / 150

[0461] 242-tone DRU-2: -150 / -126, -148 / -124, -122 / -98, -120 / -96, 116 / 102 / 140, 118 / 104 / 142, 106 / 144 / 130, 108 / 146 / 132

[0462] Example 1-2 Base pilot tone position

[0463] Example 1-2 relates to a scheme in which one subcarrier is allocated to each of 18 26-tone DRUs in order from the lowest available subcarrier to the highest available subcarrier below the DC subcarrier (i.e., subcarriers with negative indices), and subcarriers that are mirror symmetrical with respect to the allocated subcarriers and the DC subcarrier (i.e., subcarriers with positive indices) are allocated to the 26-tone DRUs including the allocated subcarriers. An example of pilot tone positions according to a scheme (Example 5-1) in which pilot tones are uniformly distributed for each of the 26-tone DRUs of Example 1-2 and DRUs of a larger size based thereon is as follows:

[0464] 26 Tone DRU-1: +-132

[0465] 26-tone DRU-2: +-131

[0466] 26-tone DRU-3: +-130

[0467] 26 Tone DRU-4: +-129

[0468] 26-tone DRU-5: +-128

[0469] 26-tone DRU-6: +-127

[0470] 26 Tone DRU-7: +-126

[0471] 26 Tone DRU-8: +-125

[0472] 26-tone DRU-9: +-124

[0473] 26 Tone DRU-10: +-123

[0474] 26-tone DRU-11: +-122

[0475] 26-tone DRU-12: +-121

[0476] 26-tone DRU-13: +-120

[0477] 26-tone DRU-14: +-119

[0478] 26-tone DRU-15: +-118

[0479] 26-tone DRU-16: +-117

[0480] 26-tone DRU-17: +-116

[0481] 26-tone DRU-18: +-115

[0482] 52 Tone DRU-1:+-{169,86}

[0483] 52-tone DRU-2: +-{168,85}

[0484] 52 Tone DRU-3:+-{167,84}

[0485] 52 Tone DRU-4:+-{166,83}

[0486] 52-tone DRU-5: +-{164,81}

[0487] 52 Tone DRU-6:+-{163,80}

[0488] 52 Tone DRU-7:+-{162,79}

[0489] 52 Tone DRU-8:+-{161,78}

[0490] 106 Tone DRU-1: +-{169 / 164,86 / 81}

[0491] 106 Tone DRU-2: +-{168 / 163,85 / 80}

[0492] 106 Tone DRU-3: +-{162 / 167,79 / 84}

[0493] 106 Tone DRU-4: +-{161 / 166,78 / 83}

[0494] 242 Tone DRU-1: +-{196 / 198, 147 / 149, 99 / 102, 52 / 53}

[0495] 242 Tone DRU-2: +-{195 / 194, 148 / 145, 100 / 98, 51 / 49}

[0496] For the 26-tone DRU of Example 1-2 and a DRU of a larger size based thereon, examples of pilot tone positions according to a scheme (Example 5-2) in which pilot tones are uniformly distributed among tones with even indexes are as follows.

[0497] 26 Tone DRU-1: +-132

[0498] 26-tone DRU-2: +-150

[0499] 26-tone DRU-3: +-130

[0500] 26-tone DRU-4: +-148

[0501] 26-tone DRU-5: +-128

[0502] 26-tone DRU-6: +-146 / +-108

[0503] 26 Tone DRU-7: +-126

[0504] 26-tone DRU-8: +-144 / +-106

[0505] 26-tone DRU-9: +-124

[0506] 26-tone DRU-10: +-142 / +-104

[0507] 26-tone DRU-11: +-122

[0508] 26-tone DRU-12: +-140 / +-102

[0509] 26-tone DRU-13: +-120

[0510] 26-tone DRU-14: +-138 / +-100

[0511] 26-tone DRU-15: +-118

[0512] 26-tone DRU-16: +-98

[0513] 26-tone DRU-17: +-116

[0514] 26-tone DRU-18: +-96

[0515] 52-tone DRU-1: +-{178 / 160,86}

[0516] 52-tone DRU-2: +-{168,94 / 76}

[0517] 52-tone DRU-3: +-{176 / 158,84}

[0518] 52-tone DRU-4: +-{166,92 / 74}

[0519] 52-tone DRU-5: +-{164,90 / 72}

[0520] 52-tone DRU-6: +-{172 / 154,80}

[0521] 52-tone DRU-7: +-{162,88 / 70}

[0522] 52-tone DRU-8: +-{170 / 152,78}

[0523] 106 Tone DRU-1: +-{164,86}

[0524] 106 Tone DRU-2: +-{168,80}

[0525] 106 Tone DRU-3:+-{162,84}

[0526] 106 Tone DRU-4: +-{166,78}

[0527] 242 Tone DRU-1: +-{196 / 198,146,102,52}

[0528] 242 Tone DRU-2: +-{194, 148, 100 / 98, 54 / 44}

[0529] An example of pilot tone positions according to a scheme (embodiment 5-3) in which pilot tones are uniformly distributed for the 26-tone DRU in embodiment 1-2 and the larger size DRU includes pilot tone positions within the 26-tone DRU is as follows.

[0530] 26 Tone DRU-1: +-132

[0531] 26-tone DRU-2: +-131

[0532] 26-tone DRU-3: +-130

[0533] 26 Tone DRU-4: +-129

[0534] 26-tone DRU-5: +-128

[0535] 26-tone DRU-6: +-127

[0536] 26 Tone DRU-7: +-126

[0537] 26 Tone DRU-8: +-125

[0538] 26-tone DRU-9: +-124

[0539] 26 Tone DRU-10: +-123

[0540] 26-tone DRU-11: +-122

[0541] 26-tone DRU-12: +-121

[0542] 26-tone DRU-13: +-120

[0543] 26-tone DRU-14: +-119

[0544] 26-tone DRU-15: +-118

[0545] 26-tone DRU-16: +-117

[0546] 26-tone DRU-17: +-116

[0547] 26-tone DRU-18: +-115

[0548] 52 Tone DRU-1:+-{132,123}

[0549] 52-tone DRU-2: +-{131,122}

[0550] 52 Tone DRU-3:+-{130,121}

[0551] 52 Tone DRU-4: +-{129,120}

[0552] 52 Tone DRU-5:+-{127,118}

[0553] 52 Tone DRU-6:+-{126,117}

[0554] 52 Tone DRU-7:+-{125,116}

[0555] 52 Tone DRU-8:+-{124,115}

[0556] 106 Tone DRU-1: +-{132 / 127,123 / 118}

[0557] 106 Tone DRU-2: +-{131 / 126,122 / 117}

[0558] 106 Tone DRU-3: +-{130 / 125,121 / 116}

[0559] 106 Tone DRU-4: +-{129 / 124,120 / 115}

[0560] 242 Tone DRU-1: +-{132 / 127, 130 / 125, 123 / 118, 121 / 116}

[0561] 242 Tone DRU-2: +-{131 / 126, 129 / 124, 122 / 117, 120 / 115}

[0562] For the 26-tone DRU of Example 1-2, pilot tones are uniformly distributed among tones with even indices, and the larger size DRU includes the pilot tone positions within the 26-tone DRU. An example of pilot tone positions according to this scheme (Example 5-4) is as follows:

[0563] 26 Tone DRU-1: +-132

[0564] 26-tone DRU-2: +-150

[0565] 26-tone DRU-3: +-130

[0566] 26-tone DRU-4: +-148

[0567] 26-tone DRU-5: +-128

[0568] 26-tone DRU-6: +-146 / +-108

[0569] 26 Tone DRU-7: +-126

[0570] 26-tone DRU-8: +-144 / +-106

[0571] 26-tone DRU-9: +-124

[0572] 26-tone DRU-10: +-142 / +-104

[0573] 26-tone DRU-11: +-122

[0574] 26-tone DRU-12: +-140 / +-102

[0575] 26-tone DRU-13: +-120

[0576] 26-tone DRU-14: +-138 / +-100

[0577] 26-tone DRU-15: +-118

[0578] 26-tone DRU-16: +-98

[0579] 26-tone DRU-17: +-116

[0580] 26-tone DRU-18: +-96

[0581] 52-tone DRU-1: +-{132,142 / 104}

[0582] 52-tone DRU-2: +-{150,122}

[0583] 52-tone DRU-3: +-{130,140 / 102}

[0584] 52 Tone DRU-4:+-{148,120}

[0585] 52-tone DRU-5: +-{146 / 108,118}

[0586] 52 Tone DRU-6: +-{126,98}

[0587] 52-tone DRU-7: +-{144 / 106,116}

[0588] 52-tone DRU-8: +-{124,96}

[0589] 106 Tone DRU-1: +-{132 / 146 / 108,142 / 104 / 118}

[0590] 106 Tone DRU-2: +-{150 / 126,122 / 98}

[0591] 106 Tone DRU-3: +-{130 / 144 / 106, 140 / 102 / 116}

[0592] 106 Tone DRU-4: +-{148 / 124,120 / 96}

[0593] 242 Tone DRU-1: +-{132 / 146 / 108, 130 / 144 / 106, 142 / 104 / 118, 140 / 102 / 116}

[0594] 242 Tone DRU-2: +-{150 / 126, 148 / 124, 122 / 98, 120 / 96}

[0595] In Example 5-1 regarding pilot positions, pilot tones are uniformly distributed within the DRU, and pilot tones that do not overlap with 4x LTF (LTF coefficients are mapped to every subcarrier index) can be prevented. In Example 5-2, pilot tones are limited to tones with even indexes, so they are not uniformly distributed compared to Example 4-1, but pilot tones that do not overlap with 1x LTF (LTF coefficients are mapped to every fourth subcarrier index) or 2x LTF tones (LTF coefficients are mapped to every second subcarrier index) can be prevented. In Example 5-3 or 5-4, pilot tones of a lower size are used as pilot tones of a higher size DRU, so pilot tones may be biased toward a specific frequency region compared to Example 5-1 or 5-2.

[0596] Unlike existing WLAN systems that only use RRUs, in cases where DRUs are used, the present disclosure transmits / receives one or more fields of a PPDU based on DRU tone plans of various sizes applicable to 40 MHz bandwidth PPDUs, thereby improving resource utilization efficiency. Furthermore, by defining the pilot tone positions in each DRU based on the DRU tone positions, efficient and accurate channel estimation based on pilots can be performed.

[0597] 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.

[0598] 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.

[0599] 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. The storage medium may include, but is not limited to, high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, and may include non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. Memory optionally includes one or more storage devices located remotely from the processor. The memory, or alternatively, a non-volatile memory device within the memory, comprises a non-transitory computer-readable storage medium. 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.

[0600] [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.

[0601] [Claims at the time of international application] [Claim 1] 1. A method performed by a first station (STA) in a wireless local area network (WLAN) system, comprising: generating a physical layer protocol data unit (PPDU) including one or more fields; the one or more fields are mapped onto one or more distributed resource units (DRUs); transmitting the PPDU to one or more second STAs over a bandwidth including a 40 MHz channel; where the one or more DRUs include a 26-tone DRU, the 26-tone DRU being any one of 18 previously defined 26-tone DRUs; The method wherein the pilot tones of each of the 18 predefined 26-tone DRUs are the 7th lowest subcarrier and the 7th highest subcarrier among the subcarriers included in one 26-tone DRU. [Claim 2] where the one or more DRUs include a 52-tone DRU, the 52-tone DRU being any one of eight predefined 52-tone DRUs; 2. The method of claim 1, wherein the pilot tones of each of the eight predefined 52-tone DRUs are the 9th lowest subcarrier, the 18th lowest subcarrier, the 18th highest subcarrier, and the 9th highest subcarrier among the subcarriers included in one 52-tone DRU. [Claim 3] where the one or more DRUs include a 106-tone DRU, the 106-tone DRU being any one of four previously defined 106-tone DRUs; 3. The method of claim 2, wherein the pilot tones of each of the four predefined 106-tone DRUs are the 18th lowest subcarrier, the 36th lowest subcarrier, the 36th highest subcarrier, and the 18th highest subcarrier among the subcarriers included in one 106-tone DRU. [Claim 4] where the one or more DRUs include a 242-tone DRU, the 242-tone DRU being one of two previously defined 242-tone DRUs; 4. The method of claim 3, wherein the pilot tones of each of the two predefined 242-tone DRUs are the 25th lowest subcarrier, the 49th lowest subcarrier, the 73rd lowest subcarrier, the 97th lowest subcarrier, the 97th highest subcarrier, the 73rd highest subcarrier, the 49th highest subcarrier, and the 25th highest subcarrier among the subcarriers included in one 242-tone DRU. [Claim 5] 5. The method of claim 4, wherein the n-th (n=1, 2,...,18) 26-tone DRU is defined as every 18th subcarrier, including the n-th lowest available subcarrier in the 20 MHz channel. [Claim 6] The method of claim 5, wherein the available subcarriers are subcarriers among 512 subcarriers in the 40 MHz channel excluding 5 DC (direct current) subcarriers, 16 null subcarriers, and 23 guard subcarriers. [Claim 7] The first 26-tone DRU includes subcarrier indices −243, −225, −207, −187, −169, −151, −132, −114, −95, −77, −59, −39, −21, 4, 22, 40, 60, 78, 96, 115, 133, 152, 170, 188, 208, 226; The second 26-tone DRU includes subcarrier indices −242, −224, −206, −186, −168, −150, −131, −113, −94, −76, −58, −38, −20, 5, 23, 41, 61, 79, 97, 116, 134, 153, 171, 189, 209, 227; The third 26-tone DRU includes subcarrier indices −241, −223, −205, −185, −167, −149, −130, −112, −93, −75, −55, −37, −19, 6, 24, 42, 62, 80, 98, 117, 135, 154, 172, 192, 210, 228; The fourth 26-tone DRU includes subcarrier indices −240, −222, −204, −184, −166, −148, −129, −111, −92, −74, −54, −36, −18, 7, 25, 43, 63, 81, 99, 118, 136, 155, 173, 193, 211, 229; The fifth 26-tone DRU includes subcarrier indices −239, −221, −203, −183, −165, −147, −128, −109, −91, −73, −53, −35, −17, 8, 26, 44, 64, 82, 100, 119, 138, 156, 174, 194, 212, 230; The sixth 26-tone DRU includes subcarrier indices −238, −220, −202, −182, −164, −146, −127, −108, −90, −72, −52, −34, −16, 9, 27, 45, 65, 83, 101, 120, 139, 157, 175, 195, 213, 231; The seventh 26-tone DRU includes subcarrier indices −237, −219, −201, −181, −163, −145, −126, −107, −89, −71, −51, −33, −15, 10, 28, 46, 66, 84, 102, 121, 140, 158, 176, 196, 214, 232; The eighth 26-tone DRU includes subcarrier indices −236, −218, −200, −180, −162, −144, −125, −106, −88, −70, −50, −32, −14, 11, 29, 47, 67, 85, 103, 122, 141, 159, 177, 197, 215, 233; The ninth 26-tone DRU includes subcarrier indices −235, −217, −199, −179, −161, −143, −124, −105, −87, −69, −49, −31, −13, 12, 30, 48, 68, 86, 104, 123, 142, 160, 178, 198, 216, 234; The tenth 26-tone DRU includes subcarrier indices −234, −216, −198, −178, −160, −142, −123, −104, −86, −68, −48, −30, −12, 13, 31, 49, 69, 87, 105, 124, 143, 161, 179, 199, 217, 235; The 11th 26-tone DRU includes subcarrier indices −233, −215, −197, −177, −159, −141, −122, −103, −85, −67, −47, −29, −11, 14, 32, 50, 70, 88, 106, 125, 144, 162, 180, 200, 218, and 236; The 12th 26-tone DRU includes subcarrier indices −232, −214, −196, −176, −158, −140, −121, −102, −84, −66, −46, −28, −10, 15, 33, 51, 71, 89, 107, 126, 145, 163, 181, 201, 219, and 237; The 13th 26-tone DRU includes subcarrier indices −231, −213, −195, −175, −157, −139, −120, −101, −83, −65, −45, −27, −9, 16, 34, 52, 72, 90, 108, 127, 146, 164, 182, 202, 220, and 238; The 14th 26-tone DRU includes subcarrier indices −230, −212, −194, −174, −156, −138, −119, −100, −82, −64, −44, −26, −8, 17, 35, 53, 73, 91, 109, 128, 147, 165, 183, 203, 221, 239; The 15th 26-tone DRU includes subcarrier indices −229, −211, −193, −173, −155, −136, −118, −99, −81, −63, −43, −25, −7, 18, 36, 54, 74, 92, 111, 129, 148, 166, 184, 204, 222, 240; The 16th 26-tone DRU includes subcarrier indices −228, −210, −192, −172, −154, −135, −117, −98, −80, −62, −42, −24, −6, 19, 37, 55, 75, 93, 112, 130, 149, 167, 185, 205, 223, 241; The 17th 26-tone DRU includes subcarrier indices −227, −209, −189, −171, −153, −134, −116, −97, −79, −61, −41, −23, −5, 20, 38, 58, 76, 94, 113, 131, 150, 168, 186, 206, 224, 242; and 7. The method of claim 6, wherein the eighteenth 26-tone DRU includes subcarrier indices −226, −208, −188, −170, −152, −133, −115, −96, −78, −60, −40, −22, −4, 21, 39, 59, 77, 95, 114, 132, 151, 169, 187, 207, 225, and 243. [Claim 8] the pilot tones for the first 26-tone DRU are −132, 115; the pilot tones for the second 26-tone DRU are −131, 116; the pilot tones for the third 26-tone DRU are −130, 117; the pilot tones for the fourth 26-tone DRU are −129, 118; the pilot tones for the fifth 26-tone DRU are −128, 119; the pilot tones for the sixth 26-tone DRU are −127, 120; the pilot tones for the seventh 26-tone DRU are −126, 121; the pilot tones for the eighth 26-tone DRU are −125, 122; the pilot tones for the ninth 26-tone DRU are −124, 123; the pilot tones for the tenth 26-tone DRU are −123, 124; the pilot tones for the eleventh 26-tone DRU are −122, 125; the pilot tones for the twelfth 26-tone DRU are −121, 126; the pilot tones for the thirteenth 26-tone DRU are −120, 127; the pilot tones for the fourteenth 26-tone DRU are −119, 128; the pilot tones for the fifteenth 26-tone DRU are −118, 129; the pilot tones for the sixteenth 26-tone DRU are −117, 130; The pilot tones for the seventeenth 26-tone DRU are −116, 131; and 8. The method of claim 7, wherein the pilot tones for the eighteenth 26-tone DRU are -115, 132. [Claim 9] a first 52-tone DRU includes subcarriers included in the first 26-tone DRU and the tenth 26-tone DRU; a second 52-tone DRU includes subcarriers included in the second 26-tone DRU and the eleventh 26-tone DRU; a third 52-tone DRU includes subcarriers included in the third 26-tone DRU and the twelfth 26-tone DRU; a fourth 52-tone DRU includes subcarriers included in the fourth 26-tone DRU and the thirteenth 26-tone DRU; a fifth 52-tone DRU includes subcarriers included in the sixth 26-tone DRU and the fifteenth 26-tone DRU; a sixth 52-tone DRU includes subcarriers included in the seventh 26-tone DRU and the sixteenth 26-tone DRU; a seventh 52-tone DRU that includes subcarriers included in the eighth 26-tone DRU and the seventeenth 26-tone DRU; and The method of claim 7 , wherein an eighth 52-tone DRU includes subcarriers included in the ninth 26-tone DRU and the eighteenth 26-tone DRU. [Claim 10] the pilot tones for the first 52-tone DRU are −169, −86, 78, 161; the pilot tones for the second 52-tone DRU are −168, −85, 79, 162; the pilot tones for the third 52-tone DRU are −167, −84, 80, 163; the pilot tones for the fourth 52-tone DRU are −166, −83, 81, 164; the pilot tones for the fifth 52-tone DRU are −164, −81, 83, 166; the pilot tones for the sixth 52-tone DRU are −163, −80, 84, 167; the pilot tones for the seventh 52-tone DRU are −162, −79, 85, 168; and 10. The method of claim 9, wherein the pilot tones for the eighth 52-tone DRU are -161, -78, 86, and 169. [Claim 11] a first 106-tone DRU including a first group corresponding to subcarriers included in the first 52-tone DRU and the fifth 52-tone DRU, and two of the 16 null subcarriers; a second 106-tone DRU includes a second group corresponding to subcarriers included in the second 52-tone DRU and the sixth 52-tone DRU, and the other two of the 16 null subcarriers; a third 106-tone DRU includes a third group of subcarriers included in the third 52-tone DRU and the seventh 52-tone DRU, and two more of the 16 null subcarriers; and 10. The method of claim 9, wherein a fourth 106-tone DRU includes a fourth group corresponding to subcarriers included in the fourth 52-tone DRU and the eighth 52-tone DRU, and two more of the 16 null subcarriers. [Claim 12] Based on the fact that the indices of the 16 null subcarriers are −244, −191, −190, −137, −110, −57, −56, −3, 3, 56, 57, 110, 137, 190, 191, 244, Among the first group, the second group, the third group, and the fourth group, One group includes subcarrier indexes −191 and 56, Other groups include subcarrier indexes -190, 57, Yet another group includes subcarrier indexes -57, 190, The method of claim 11 , wherein the remaining group includes subcarrier indexes −56, 191. [Claim 13] Among the pilot tones for the first 106-tone DRU, the first pilot tone is either -169 or -164, the second pilot tone is either -86 or -81, the third pilot tone is either 78 or 83, and the fourth pilot tone is either 161 or 166; Among the pilot tones for the second 106-tone DRU, a first pilot tone is either -168 or -16, a second pilot tone is either -85 or -80, a third pilot tone is either 79 or 84, and a fourth pilot tone is either 162 or 167; Among the pilot tones for the third 106-tone DRU, a first pilot tone is either -162 or -167, a second pilot tone is either -79 or -84, a third pilot tone is either 85 or 80, and a fourth pilot tone is either 168 or 163; 13. The method of claim 12, wherein, of the pilot tones for the fourth 106-tone DRU, a first pilot tone is either -161 or -166, a second pilot tone is either -78 or -83, a third pilot tone is either 86 or 81, and a fourth pilot tone is either 169 or 164. [Claim 14] the first 242-tone DRU includes a fifth group corresponding to subcarriers included in the first 106-tone DRU, the third 106-tone DRU, and the fifth 26-tone DRU, and four of eight null subcarriers; 12. The method of claim 11, wherein a second 242-tone DRU includes a sixth group of subcarriers included in the second 106-tone DRU, the fourth 106-tone DRU, and the fourteenth 26-tone DRU, as well as the other four of the eight null subcarriers. [Claim 15] Based on the indexes of the eight null subcarriers being −244, −137, −110, −3, 3, 110, 137, 244, Among the fifth group and the sixth group, One group includes subcarrier indices -137, -3, 110, and 244. The method of claim 14 , wherein another group includes subcarrier indices −244, −110, 3, and 137. [Claim 16] Of the eight pilot tones for the first 242-tone DRU, the first pilot tone is either -196 or -198, the second pilot tone is either -147 or -149, the third pilot tone is either -99 or -102, the fourth pilot tone is either -52 or -53, the fifth pilot tone is either 51 or 49, the sixth pilot tone is either 100 or 98, the seventh pilot tone is either 148 or 145, and the eighth pilot tone is either 195 or 194; 16. The method of claim 15, wherein of the eight pilot tones for the second 242-tone DRU, a first pilot tone is either −195 or −194, a second pilot tone is either −148 or −145, a third pilot tone is either −100 or −98, a fourth pilot tone is either −51 or −49, a fifth pilot tone is either 52 or 53, a sixth pilot tone is either 99 or 102, a seventh pilot tone is either 147 or 149, and an eighth pilot tone is either 196 or 198. [Claim 17] Based on the PPDU being a downlink PPDU, the one or more DRUs for the downlink PPDU are indicated based on resource unit (RU) allocation information included in the downlink PPDU; or The method of claim 1, wherein, based on the PPDU being an uplink TB PPDU, the one or more DRUs for the uplink TB PPDU are indicated based on RU allocation information included in a trigger frame that triggers transmission of the uplink TB PPDU. [Claim 18] The method of claim 1 , wherein the one or more fields include a data field. [Claim 19] 1. A first station (STA) device in a wireless local area network (WLAN) system, comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; the one or more processors: Generate a physical layer protocol data unit (PPDU) containing one or more fields; The one or more fields are mapped onto one or more distributed resource units (DRUs); transmit the PPDU to one or more second STAs via the one or more transceivers over a bandwidth that includes a 40 MHz channel; where the one or more DRUs include a 26-tone DRU, the 26-tone DRU being any one of 18 previously defined 26-tone DRUs; The apparatus, wherein the pilot tones of each of the 18 predefined 26-tone DRUs are the 7th lowest subcarrier and the 7th highest subcarrier among the subcarriers included in one 26-tone DRU. [Claim 20] 1. A method performed by a second station (STA) in a wireless local area network (WLAN) system, comprising: receiving a physical layer protocol data unit (PPDU) from a first STA, the PPDU including one or more fields on a bandwidth including a 40 MHz channel; decoding the one or more fields mapped onto one or more distributed resource units (DRUs); where the one or more DRUs include a 26-tone DRU, the 26-tone DRU being any one of 18 previously defined 26-tone DRUs; A method wherein the pilot tones of each of the 18 predefined 26-tone DRUs are the 7th lowest subcarrier and the 7th highest subcarrier among the subcarriers included in one 26-tone DRU. [Claim 21] A second station (STA) device in a wireless local area network (WLAN) system, comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; the one or more processors: receiving a physical layer protocol data unit (PPDU) including one or more fields from a first STA via the one or more transceivers on a bandwidth including a 40 MHz channel; Decode the one or more fields mapped onto one or more distributed resource units (DRUs); where the one or more DRUs include a 26-tone DRU, the 26-tone DRU being any one of 18 previously defined 26-tone DRUs; The apparatus, wherein the pilot tones of each of the 18 predefined 26-tone DRUs are the 7th lowest subcarrier and the 7th highest subcarrier among the subcarriers included in one 26-tone DRU. [Claim 22] 1. A processing device configured to control a station (STA) in a wireless local area network (WLAN) system, comprising: one or more processors; and one or more computer memories operably coupled to the one or more processors and storing instructions that, when executed by the one or more processors, perform the method of any one of claims 1 to 17. [Claim 23] one or more non-transitory computer-readable media storing one or more instructions, A computer-readable medium, the one or more instructions being executed by one or more processors to control a device in a wireless LAN system to perform the method of any one of claims 1 to 17.

Claims

1. 1. A method performed by a first station (STA) in a wireless local area network (WLAN) system, comprising: generating a physical layer protocol data unit (PPDU) including one or more fields; the one or more fields are mapped onto one or more distributed resource units (DRUs); transmitting the PPDU to one or more second STAs over a bandwidth including a 40 MHz channel; Based on the one or more DRUs including a 26-tone DRU, the 26-tone DRU is any one of 18 predefined 26-tone DRUs; A method in which the pilot tones of each of the 18 predefined 26-tone DRUs are the 7th lowest subcarrier and the 7th highest subcarrier among the subcarriers included in one 26-tone DRU.

2. Based on the one or more DRUs including a 52-tone DRU, the 52-tone DRU is any one of eight predefined 52-tone DRUs; 2. The method of claim 1, wherein the pilot tones of each of the eight predefined 52-tone DRUs are the 9th lowest subcarrier, the 18th lowest subcarrier, the 18th highest subcarrier, and the 9th highest subcarrier among the subcarriers included in one 52-tone DRU.

3. The one or more DRUs include a 106-tone DRU, and the 106-tone DRU is any one of four predefined 106-tone DRUs; 3. The method of claim 2, wherein the pilot tones of each of the four predefined 106-tone DRUs are the 18th lowest subcarrier, the 36th lowest subcarrier, the 36th highest subcarrier, and the 18th highest subcarrier among the subcarriers included in one 106-tone DRU.

4. Based on the one or more DRUs including a 242-tone DRU, the 242-tone DRU is any one of two previously defined 242-tone DRUs; 4. The method of claim 3, wherein the pilot tones of each of the two predefined 242-tone DRUs are the 25th lowest subcarrier, the 49th lowest subcarrier, the 73rd lowest subcarrier, the 97th lowest subcarrier, the 97th highest subcarrier, the 73rd highest subcarrier, the 49th highest subcarrier, and the 25th highest subcarrier among the subcarriers included in one 242-tone DRU.

5. 5. The method of claim 4, wherein the n-th (n=1, 2, . . . , 18) 26-tone DRU is defined as every 18th subcarrier, including the n-th lowest available subcarrier in the 20 MHz channel.

6. 6. The method of claim 5, wherein the available subcarriers are subcarriers excluding 5 direct current (DC) subcarriers, 16 null subcarriers, and 23 guard subcarriers among 512 subcarriers in the 40 MHz channel.

7. The first 26-tone DRU includes subcarrier indices −243, −225, −207, −187, −169, −151, −132, −114, −95, −77, −59, −39, −21, 4, 22, 40, 60, 78, 96, 115, 133, 152, 170, 188, 208, 226; The second 26-tone DRU includes subcarrier indices −242, −224, −206, −186, −168, −150, −131, −113, −94, −76, −58, −38, −20, 5, 23, 41, 61, 79, 97, 116, 134, 153, 171, 189, 209, 227; the third 26-tone DRU includes subcarrier indices −241, −223, −205, −185, −167, −149, −130, −112, −93, −75, −55, −37, −19, 6, 24, 42, 62, 80, 98, 117, 135, 154, 172, 192, 210, 228; The fourth 26-tone DRU includes subcarrier indices −240, −222, −204, −184, −166, −148, −129, −111, −92, −74, −54, −36, −18, 7, 25, 43, 63, 81, 99, 118, 136, 155, 173, 193, 211, 229; The fifth 26-tone DRU includes subcarrier indices −239, −221, −203, −183, −165, −147, −128, −109, −91, −73, −53, −35, −17, 8, 26, 44, 64, 82, 100, 119, 138, 156, 174, 194, 212, 230; The sixth 26-tone DRU includes subcarrier indices −238, −220, −202, −182, −164, −146, −127, −108, −90, −72, −52, −34, −16, 9, 27, 45, 65, 83, 101, 120, 139, 157, 175, 195, 213, 231; The seventh 26-tone DRU includes subcarrier indices −237, −219, −201, −181, −163, −145, −126, −107, −89, −71, −51, −33, −15, 10, 28, 46, 66, 84, 102, 121, 140, 158, 176, 196, 214, 232; The eighth 26-tone DRU includes subcarrier indices −236, −218, −200, −180, −162, −144, −125, −106, −88, −70, −50, −32, −14, 11, 29, 47, 67, 85, 103, 122, 141, 159, 177, 197, 215, 233; The ninth 26-tone DRU includes subcarrier indices −235, −217, −199, −179, −161, −143, −124, −105, −87, −69, −49, −31, −13, 12, 30, 48, 68, 86, 104, 123, 142, 160, 178, 198, 216, 234; The tenth 26-tone DRU includes subcarrier indices −234, −216, −198, −178, −160, −142, −123, −104, −86, −68, −48, −30, −12, 13, 31, 49, 69, 87, 105, 124, 143, 161, 179, 199, 217, 235; The eleventh 26-tone DRU includes subcarrier indices −233, −215, −197, −177, −159, −141, −122, −103, −85, −67, −47, −29, −11, 14, 32, 50, 70, 88, 106, 125, 144, 162, 180, 200, 218, and 236; The twelfth 26-tone DRU includes subcarrier indices −232, −214, −196, −176, −158, −140, −121, −102, −84, −66, −46, −28, −10, 15, 33, 51, 71, 89, 107, 126, 145, 163, 181, 201, 219, 237; The thirteenth 26-tone DRU includes subcarrier indices −231, −213, −195, −175, −157, −139, −120, −101, −83, −65, −45, −27, −9, 16, 34, 52, 72, 90, 108, 127, 146, 164, 182, 202, 220, 238; The fourteenth 26-tone DRU includes subcarrier indices −230, −212, −194, −174, −156, −138, −119, −100, −82, −64, −44, −26, −8, 17, 35, 53, 73, 91, 109, 128, 147, 165, 183, 203, 221, 239; The fifteenth 26-tone DRU includes subcarrier indices −229, −211, −193, −173, −155, −136, −118, −99, −81, −63, −43, −25, −7, 18, 36, 54, 74, 92, 111, 129, 148, 166, 184, 204, 222, 240; The sixteenth 26-tone DRU includes subcarrier indices −228, −210, −192, −172, −154, −135, −117, −98, −80, −62, −42, −24, −6, 19, 37, 55, 75, 93, 112, 130, 149, 167, 185, 205, 223, 241; The seventeenth 26-tone DRU includes subcarrier indices −227, −209, −189, −171, −153, −134, −116, −97, −79, −61, −41, −23, −5, 20, 38, 58, 76, 94, 113, 131, 150, 168, 186, 206, 224, 242; and 7. The method of claim 6, wherein the eighteenth 26-tone DRU includes subcarrier indices −226, −208, −188, −170, −152, −133, −115, −96, −78, −60, −40, −22, −4, 21, 39, 59, 77, 95, 114, 132, 151, 169, 187, 207, 225, and 243.

8. the pilot tones for the first 26-tone DRU are −132, 115; the pilot tones for the second 26-tone DRU are −131, 116; the pilot tones for the third 26-tone DRU are −130, 117; the pilot tones for the fourth 26-tone DRU are −129, 118; the pilot tones for the fifth 26-tone DRU are −128, 119; the pilot tones for the sixth 26-tone DRU are −127, 120; the pilot tones for the seventh 26-tone DRU are −126, 121; the pilot tones for the eighth 26-tone DRU are −125, 122; the pilot tones for the ninth 26-tone DRU are −124, 123; the pilot tones for the tenth 26-tone DRU are −123, 124; the pilot tones for the eleventh 26-tone DRU are −122, 125; the pilot tones for the twelfth 26-tone DRU are −121, 126; the pilot tones for the thirteenth 26-tone DRU are −120, 127; the pilot tones for the fourteenth 26-tone DRU are −119, 128; the pilot tones for the fifteenth 26-tone DRU are −118, 129; The pilot tones for the sixteenth 26-tone DRU are −117, 130; The pilot tones for the seventeenth 26-tone DRU are −116, 131; and 8. The method of claim 7, wherein the pilot tones for the eighteenth 26-tone DRU are -115,132.

9. a first 52-tone DRU includes subcarriers included in the first 26-tone DRU and the tenth 26-tone DRU; a second 52-tone DRU includes subcarriers included in the second 26-tone DRU and the eleventh 26-tone DRU; a third 52-tone DRU includes subcarriers included in the third 26-tone DRU and the twelfth 26-tone DRU; a fourth 52-tone DRU includes subcarriers included in the fourth 26-tone DRU and the thirteenth 26-tone DRU; a fifth 52-tone DRU includes subcarriers included in the sixth 26-tone DRU and the fifteenth 26-tone DRU; a sixth 52-tone DRU includes subcarriers included in the seventh 26-tone DRU and the sixteenth 26-tone DRU; a seventh 52-tone DRU includes subcarriers included in the eighth 26-tone DRU and the seventeenth 26-tone DRU; and The method of claim 7 , wherein an eighth 52-tone DRU includes subcarriers included in the ninth 26-tone DRU and the eighteenth 26-tone DRU.

10. the pilot tones for the first 52-tone DRU are −169, −86, 78, 161; the pilot tones for the second 52-tone DRU are −168, −85, 79, 162; the pilot tones for the third 52-tone DRU are −167, −84, 80, 163; the pilot tones for the fourth 52-tone DRU are −166, −83, 81, 164; the pilot tones for the fifth 52-tone DRU are −164, −81, 83, 166; the pilot tones for the sixth 52-tone DRU are −163, −80, 84, 167; the pilot tones for the seventh 52-tone DRU are −162, −79, 85, 168; and 10. The method of claim 9, wherein the pilot tones for the eighth 52-tone DRU are -161, -78, 86, and 169.

11. a first 106-tone DRU includes subcarriers included in the first 52-tone DRU and the fifth 52-tone DRU, and a first group corresponding to two of the 16 null subcarriers; a second 106-tone DRU includes a second group corresponding to subcarriers included in the second 52-tone DRU and the sixth 52-tone DRU, and other two of the 16 null subcarriers; a third 106-tone DRU includes a third group corresponding to subcarriers included in the third 52-tone DRU and the seventh 52-tone DRU, and two more of the 16 null subcarriers; and 10. The method of claim 9, wherein a fourth 106-tone DRU includes a fourth group corresponding to subcarriers included in the fourth 52-tone DRU and the eighth 52-tone DRU, and two more of the 16 null subcarriers.

12. Based on the fact that the indices of the 16 null subcarriers are −244, −191, −190, −137, −110, −57, −56, −3, 3, 56, 57, 110, 137, 190, 191, 244, Among the first group, the second group, the third group, and the fourth group, One group includes subcarrier indexes −191, 56, Another group includes subcarrier indexes −190, 57; Yet another group includes subcarrier indexes −57 and 190; The method of claim 11, wherein the remaining group includes subcarrier indexes −56, 191.

13. Among the pilot tones for the first 106-tone DRU, a first pilot tone is either −169 or −164, a second pilot tone is either −86 or −81, a third pilot tone is either 78 or 83, and a fourth pilot tone is either 161 or 166; Among the pilot tones for the second 106-tone DRU, a first pilot tone is either −168 or −16, a second pilot tone is either −85 or −80, a third pilot tone is either 79 or 84, and a fourth pilot tone is either 162 or 167; Among the pilot tones for the third 106-tone DRU, a first pilot tone is either −162 or −167, a second pilot tone is either −79 or −84, a third pilot tone is either 85 or 80, and a fourth pilot tone is either 168 or 163; 13. The method of claim 12, wherein, of the pilot tones for the fourth 106-tone DRU, a first pilot tone is either -161 or -166, a second pilot tone is either -78 or -83, a third pilot tone is either 86 or 81, and a fourth pilot tone is either 169 or 164.

14. the first 242-tone DRU includes a fifth group corresponding to subcarriers included in the first 106-tone DRU, the third 106-tone DRU, and the fifth 26-tone DRU, and four of eight null subcarriers; 12. The method of claim 11, wherein a second 242-tone DRU includes a sixth group corresponding to subcarriers included in the second 106-tone DRU, the fourth 106-tone DRU, and the fourteenth 26-tone DRU, and the other four of the eight null subcarriers.

15. Based on the indexes of the eight null subcarriers being −244, −137, −110, −3, 3, 110, 137, and 244, Among the fifth group and the sixth group, One group includes subcarrier indexes −137, −3, 110, and 244, The method of claim 14, wherein another group includes subcarrier indices −244, −110, 3, and 137.

16. Of the eight pilot tones for the first 242-tone DRU, the first pilot tone is either −196 or −198, the second pilot tone is either −147 or −149, the third pilot tone is either −99 or −102, the fourth pilot tone is either −52 or −53, the fifth pilot tone is either 51 or 49, the sixth pilot tone is either 100 or 98, the seventh pilot tone is either 148 or 145, and the eighth pilot tone is either 195 or 194; 16. The method of claim 15, wherein of the eight pilot tones for the second 242-tone DRU, a first pilot tone is either −195 or −194, a second pilot tone is either −148 or −145, a third pilot tone is either −100 or −98, a fourth pilot tone is either −51 or −49, a fifth pilot tone is either 52 or 53, a sixth pilot tone is either 99 or 102, a seventh pilot tone is either 147 or 149, and an eighth pilot tone is either 196 or 198.

17. Based on the PPDU being a downlink PPDU, the one or more DRUs for the downlink PPDU are indicated based on resource unit (RU) allocation information included in the downlink PPDU; or 2. The method of claim 1, wherein, based on the PPDU being an uplink TB PPDU, the one or more DRUs for the uplink TB PPDU are indicated based on RU allocation information included in a trigger frame that triggers transmission of the uplink TB PPDU.

18. The method of claim 1 , wherein the one or more fields include a data field.

19. 1. A first station (STA) device in a wireless local area network (WLAN) system, comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: generating a physical layer protocol data unit (PPDU) including one or more fields; The one or more fields are mapped onto one or more distributed resource units (DRUs); transmit the PPDU to one or more second STAs via the one or more transceivers over a bandwidth including a 40 MHz channel; Based on the one or more DRUs including a 26-tone DRU, the 26-tone DRU is any one of 18 predefined 26-tone DRUs; An apparatus, wherein the pilot tones of each of the 18 predefined 26-tone DRUs are the 7th lowest subcarrier and the 7th highest subcarrier among the subcarriers included in one 26-tone DRU.

20. 1. A method performed by a second station (STA) in a wireless local area network (WLAN) system, comprising: receiving a physical layer protocol data unit (PPDU) including one or more fields on a bandwidth including a 40 MHz channel from a first STA; decoding the one or more fields mapped onto one or more distributed resource units (DRUs); Based on the one or more DRUs including a 26-tone DRU, the 26-tone DRU is any one of 18 predefined 26-tone DRUs; A method in which the pilot tones of each of the 18 predefined 26-tone DRUs are the 7th lowest subcarrier and the 7th highest subcarrier among the subcarriers included in one 26-tone DRU.

21. A second station (STA) device in a wireless local area network (WLAN) system, comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: receiving a physical layer protocol data unit (PPDU) including one or more fields on a bandwidth including a 40 MHz channel from a first STA via the one or more transceivers; Decode the one or more fields mapped onto one or more distributed resource units (DRUs); Based on the one or more DRUs including a 26-tone DRU, the 26-tone DRU is any one of 18 predefined 26-tone DRUs; An apparatus, wherein the pilot tones of each of the 18 predefined 26-tone DRUs are the 7th lowest subcarrier and the 7th highest subcarrier among the subcarriers included in one 26-tone DRU.

22. 1. A processing device configured to control a station (STA) in a wireless local area network (WLAN) system, comprising: one or more processors; and one or more computer memories operatively coupled to the one or more processors and storing instructions that, when executed by the one or more processors, perform the method of any one of claims 1 to 17.

23. one or more non-transitory computer-readable media storing one or more instructions, A computer readable medium, wherein the one or more instructions are executed by one or more processors to control devices in a wireless LAN system to perform the method of any one of claims 1 to 17.

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