Transmission or reception method and apparatus based on distributed resource unit tone plan in wireless LAN system

Abstract

Disclosed are a transmission or reception method and apparatus based on a distributed resource unit tone plan in a wireless LAN system. According to one embodiment of the present disclosure, a method performed by a first STA in a wireless local area network (WLAN) system may comprise the steps of: generating a PPDU including one or more fields, in which the one or more fields are mapped on one or more DRUs; and transmitting the PPDU to the one or more second STAs over a bandwidth including the 20 MHz channel. A 26-tone DRU is included based on the one or more DRUs, the 26-tone DRU is one of nine predefined 26-tone DRUs, and an nth (n = 1, 2,..., 9) 26-tone DRU may be defined to include an nth lowest subcarrier among available subcarriers in the 20 MHz channel based on each nth subcarrier of the nth lowest subcarrier.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a transmission or reception method and apparatus based on a distributed resource unit tone plan in a wireless local area network (WLAN) system. BACKGROUND

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

[0003] In order to provide a more advanced wireless communication environment, improved technologies for extremely high throughput (EHT) are being discussed. For example, technologies for MIMO and multi-access point (AP) coordination that support increased bandwidth, efficient use of multiple frequency bands, and increased spatial streams are being researched, and in particular, various technologies are being researched to support low latency or real-time traffic. In addition, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technologies. SUMMARY

[0004] TECHNICAL PROBLEM

[0005] The technical problem of the disclosure is to provide a transmission or reception method and apparatus based on a distributed resource unit tone plan in a WLAN system.

[0006] The technical objects to be achieved by the disclosure are not limited to the aforementioned technical objects and other technical objects not described herein will be clearly understood from the following description by one of ordinary skill in the art.

[0007] TECHNICAL SOLUTION

[0008] According to an aspect of the disclosure, a method performed by a first station (STA) in a wireless local area network (WLAN) system can include generating a physical layer protocol data unit (PPDU) including one or more fields mapped on one or more distributed resource units (DRUs), and transmitting the PPDU to one or more second STAs on a bandwidth including a 20 MHz channel. Based on the one or more DRUs including 26-tone DRUs, the 26-tone DRUs can be one of 9 predefined 26-tone DRUs, an nth(n=1, 2,..., 9) 26-tone DRU can include an nth lowest subcarrier among available subcarriers in the 20 MHz channel, and can be defined as every 9th subcarrier from the nth lowest subcarrier. Here, the available subcarriers can be subcarriers excluding 7 direct current (DC) subcarriers, 4 null subcarriers, 11 guard subcarriers, and 18 pilot subcarriers among 256 subcarriers within the 20 MHz channel.

[0009] According to an additional aspect of the disclosure, a method performed by a second station (STA) in a wireless local area network (WLAN) system can include receiving a physical layer protocol data unit (PPDU) including one or more fields from a first STA on a bandwidth including a 20 MHz channel, and decoding the one or more fields mapped on one or more distributed resource units (DRUs). Based on the one or more DRUs including 26-tone DRUs, the 26-tone DRUs can be one of 9 predefined 26-tone DRUs, an nth(n=1, 2,..., 9) 26-tone DRU can include an nth lowest subcarrier among available subcarriers in the 20 MHz channel, and can be defined as every 9th subcarrier from the nth lowest subcarrier. Here, the available subcarriers can be subcarriers excluding 7 direct current (DC) subcarriers, 4 null subcarriers, 11 guard subcarriers, and 18 pilot subcarriers among 256 subcarriers within the 20 MHz channel.

[0010] Technical Effects

[0011] According to the disclosure, a transmission or reception method and apparatus based on a distributed resource unit tone plan in a WLAN system can be provided.

[0012] The effects achievable by the disclosure are not limited to the above-described effects, and other effects not described herein can be clearly understood by a person skilled in the art from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings, which are included as part of the specific embodiments for understanding the disclosure, provide embodiments of the disclosure and, together with the specific embodiments, describe technical features of the disclosure.

[0014] Figure 1 FIG. 1 is a configuration block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0015] Figure 2 FIG. 2 is a diagram illustrating an exemplary structure of a WLAN system to which the present disclosure can be applied.

[0016] Figure 3 FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0017] Figure 4 FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0018] Figure 5 FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0019] Figure 6 FIG. 6 is a diagram for explaining an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0020] Figure 7 FIG. 7 is a diagram illustrating an example of a PPDU defined in an IEEE 802.11 standard to which the present disclosure can be applied.

[0021] Figures 8 to 10 FIG. 8 is a diagram for explaining an example of a resource unit of a WLAN system to which the present disclosure can be applied.

[0022] Figure 11 FIG. 9 is a diagram for explaining an example of a DRU to which the present disclosure can be applied.

[0023] Figure 12 FIG. 10 is a diagram representing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0024] Figure 13 FIG. 11 is a diagram for explaining an example of a DRU tone plan-based PPDU reception method of a first STA according to the present disclosure.

[0025] Figure 14 FIG. 12 is a diagram for explaining an example of a DRU tone plan-based PPDU transmission method of a second STA according to the present disclosure.

[0026] Figure 15 FIG. 13 is a diagram for explaining a PPDU transmission and reception procedure between a transmitting STA and a receiving STA according to an example of the present disclosure. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed through the accompanying drawings is to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure can be implemented. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure can be practiced without these specific details.

[0028] In some cases, known structures and devices can be omitted or can be shown in block diagram form, based on a core function thereof, in order to facilitate the understanding of the present disclosure, rather than to show every specific detail of the present disclosure.

[0029] In the present disclosure, when an element is referred to as being "connected", "combined", or "linked" to another element, it can include an indirect connection relationship between the other element and the element through another element therebetween as well as a direct connection relationship. Also, in the present disclosure, the term "comprising" or "having" specifies the existence of the mentioned features, steps, operations, components, and / or elements, but does not exclude the existence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0030] In the present disclosure, terms such as "first", "second", and the like are used only to distinguish one element from another element, and are not used to limit the elements, unless otherwise specified, and do not limit the order or importance between the elements, etc. Therefore, within the scope of the present disclosure, a first element in an embodiment can be referred to as a second element in another embodiment, and likewise, a second element in an embodiment can be referred to as a first element in another embodiment.

[0031] The terms used in the present disclosure are to describe specific embodiments, and are not intended to limit the claims. As used in the description of the embodiments and the appended claims, the singular form is intended to include the plural forms, unless the context clearly dictates otherwise. The term "and / or" used in the present disclosure can refer to one of the relevant listed items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise specified, " / " and "and / or" between words in the present disclosure have the same meaning.

[0032] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to wireless LAN systems. For example, examples of the present disclosure can be applied to wireless LANs based on IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to wireless LANs based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to wireless LANs based on the IEEE802.11be version 2 standard corresponding to the additional enhanced technology of the IEEE 802.11be version 1 standard. In addition, examples of the present disclosure can be applied to wireless LANs based on the next generation standard after IEEE 802.11be. In addition, examples of the present disclosure can be applied to cellular wireless communication systems. For example, it can be applied to cellular wireless communication systems based on long term evolution (LTE) technology and 5G new radio (NR) technology based on the third generation partnership project (3GPP) standard.

[0033] Hereinafter, technical features of examples to which the present disclosure can be applied will be described.

[0034] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0035] Figure 1 The first device 100 and the second device 200 illustrated in the example may be replaced with various terms such as terminal, wireless device, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), user terminal (UT), mobile subscriber station (MSS), mobile subscriber unit (MSU), subscriber station (SS), advanced mobile station (AMS), wireless terminal (WT), or simply user. In addition, the first device 100 and the second device 200 include an access point (AP), a base station (BS), a fixed station, a node B, a base transceiver system (BTS), and a network. It may be replaced with various terms such as an artificial intelligence (AI) system, a roadside unit (RSU), a repeater, a router, a relay, and a gateway.

[0036] Figure 1 The devices 100 and 200 illustrated in FIG. 1 may be referred to as stations (STAs). Figure 1The apparatuses 100 and 200 exemplified can be referred to with various terms such as a transmitting apparatus, a receiving apparatus, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 can perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 can perform the functions of an AP and / or a non-AP. When the STAs 110 and 200 perform the AP function, they can be simply referred to as an AP, and when the STAs 110 and 200 perform the non-AP function, they can be simply referred to as a STA. In addition, in the present disclosure, the AP can also be indicated as an AP STA.

[0037] Referring to Figure 1 The first apparatus 100 and the second apparatus 200 can transmit and receive radio signals through various wireless LAN technologies (for example, IEEE 802.11 series). The first apparatus 100 and the second apparatus 200 can include an interface for a medium access control (MAC) layer and a physical layer (PHY) to comply with the IEEE 802.11 standard.

[0038] In addition, the first apparatus 100 and the second apparatus 200 can additionally support various communication standard (for example, 3GPP LTE series, 5G NR series standards, etc.) technologies in addition to the wireless LAN technology. In addition, the apparatuses of the present disclosure can be implemented in various apparatuses such as a mobile phone, a vehicle, a personal computer, an augmented reality (AR) apparatus, and a virtual reality (VR) apparatus, etc. In addition, the STAs of the present specification can support various communication services such as a voice call, a video call, data communication, autonomous driving, machine type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), IoT (Internet of Things), etc.

[0039] The first apparatus 100 can include one or more processors 102 and one or more memories 104, and can additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 can control the memory 104 and / or the transceiver 106, and can be configured to implement descriptions, functions, procedures, suggestions, methods and / or operational flowcharts included in the present disclosure. For example, the processor 102 can generate first information / signal by processing information in the memory 104, and then transmit a wireless signal including the first information / signal through the transceiver 106. Also, the processor 102 can receive a wireless signal including second information / signal through the transceiver 106, and then store information obtained by processing a signal of the second information / signal in the memory 104. The memory 104 can be connected to the processor 102 and can store a variety of information related to operations of the processor 102. For example, the memory 104 can store software code including instructions for performing all or a part of processes controlled by the processor 102 or for performing descriptions, functions, procedures, suggestions, methods and / or operational flowcharts included in the present disclosure. Here, the processor 102 and the memory 104 can be a part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 106 can be connected to the processor 102 and can transmit and / or receive a wireless signal through the one or more antennas 108. The transceiver 106 can include a transmitter and / or a receiver. The transceiver 106 can be used together with an RF (Radio Frequency) unit. In the present disclosure, a wireless device can mean a communication modem / circuit / chip.

[0040] The second device 200 can include one or more processors 202 and one or more memories 204, and can additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 can control the memory 204 and / or the transceiver 206, and can be configured to implement descriptions, functions, procedures, suggestions, methods and / or operational flowcharts included in the present disclosure. For example, the processor 202 can generate third information / signal by processing information in the memory 204, and then transmit a wireless signal including the third information / signal through the transceiver 206. In addition, the processor 202 can receive a wireless signal including fourth information / signal through the transceiver 206, and then store information obtained by signal processing through the fourth information / signal in the memory 204. The memory 204 can be connected to the processor 202 and can store a variety of information related to operations of the processor 202. For example, the memory 204 can store software code including instructions for performing all or part of processes controlled by the processor 202 or for performing descriptions, functions, procedures, suggestions, methods and / or operational flowcharts included in the present disclosure. Here, the processor 202 and the memory 204 can be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 206 can be connected to the processor 202 and can transmit and / or receive a wireless signal through the one or more antennas 208. The transceiver 206 can include a transmitter and / or a receiver. The transceiver 206 can be used together with an RF unit. In the present disclosure, a device can mean a communication modem / circuit / chip.

[0041] Hereinafter, the hardware elements of the apparatuses 100, 200 will be described in more detail. Without limitation, one or more protocol layers can be implemented by the one or more processors 102, 202. For example, the one or more processors 102, 202 can implement one or more layers (e.g., functional layers such as PHY, MAC). The one or more processors 102, 202 can generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. The one or more processors 102, 202 can generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. The one or more processors 102, 202 can generate signals (e.g., baseband signals) including the PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed in the present disclosure to provide the same 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 according to the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts included in the present disclosure, and obtain the PDUs, SDUs, messages, control information, data, or information.

[0042] The one or more processors 102, 202 can be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102, 202 can be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processors Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) can be included in the one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts included in the present disclosure can be implemented by using firmware or software, and the firmware or software can be implemented as including modules, procedures, functions, etc. The firmware or software configured to perform the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts included in the present disclosure can be included in the one or more processors 102, 202, or can be stored in the one or more memories 104, 204 and driven by the one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts included in the present disclosure can be implemented by using firmware or software in the form of codes, instructions, and / or instruction sets.

[0043] One or more memories 104, 204 can be connected to one or more processors 102, 202 and can store data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. One or more memories 104, 204 can be configured with ROM, RAM, EPROM, flash memory, hard drives, registers, cache memories, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 can be located internal and / or external to one or more processors 102, 202. In addition, one or more memories 104, 204 can be connected to one or more processors 102, 202 by various technologies such as wired or wireless connections.

[0044] The one or more transceivers 106, 206 can transmit user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operational flowcharts, etc. of the disclosure to one or more other apparatuses. The one or more transceivers 106, 206 can receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods and / or operational flowcharts, etc. included in the disclosure from one or more other apparatuses. For example, the one or more transceivers 106, 206 can be connected to the one or more processors 102, 202 and can transmit and receive wireless signals. For example, the one or more processors 102, 202 can control the one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other apparatuses. In addition, the one or more processors 102, 202 can control the one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other apparatuses. In addition, the one or more transceivers 106, 206 can be connected to the one or more antennas 108, 208, and the one or more transceivers 106, 206 can be configured to transmit and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods and / or operational flowcharts, etc. included in the disclosure through the one or more antennas 108, 208. In the disclosure, the one or more antennas can be a plurality of physical antennas or a plurality of logical antennas (for example, antenna ports). The one or more transceivers 106, 206 can convert received wireless signals / channels, etc. from RF band signals to baseband signals to process received user data, control information, wireless signals / channels, etc. by using the one or more processors 102, 202. The one or more transceivers 106, 206 can convert user data, control information, wireless signals / channels, etc. processed by using the one or more processors 102, 202 from baseband signals to RF band signals. Accordingly, the one or more transceivers 106, 206 can include (analog) oscillators and / or filters.

[0045] For example, one of the STAs 100 and 200 can perform the intended operation of an AP, and the other of the STAs 100 and 200 can perform the intended operation of a non-AP STA. For example, Figure 1 The transceivers 106 and 206 of the STA 100 and 200 can perform transmission and reception operations of signals (for example, packets or physical layer protocol data units (PPDUs) conforming to IEEE 802.11a / b / g / n / ac / ax / be / bn). In addition, in the disclosure, operations in which various STAs generate transmission / reception signals or perform data processing or calculation in advance for transmission / reception signals can be performed by the one or more processors 102, 202. Figure 1The operations of generating a transmission / reception signal or performing data processing or calculation in advance for the operations of the transmission / reception signal can include, for example, 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of a field (a signal (SIG), a short training field (STF), a long training field (LTF), data, etc.) included in a PPDU, 2) determining / configuring / acquiring a time resource or a frequency resource (e.g., a subcarrier resource) for a field (a SIG, an STF, an LTF, data, etc.) included in a PPDU, 3) determining / configuring / acquiring a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an additional sequence applied to a SIG) for a field (a SIG, an STF, an LTF, data, etc.) included in a PPDU action, 4) a power control operation and / or a power saving operation applied to a STA, 5) an operation related to an ACK signal determination / acquisition / configuration / calculation / decoding / encoding, etc. In addition, in the following examples, various information (e.g., information related to a field / subfield / control field / parameter / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode a transmission signal and a reception signal can be stored in the memories 104 and 204 of the processors 102 and 202. Figure 1

[0046] Hereinafter, a downlink (DL) can mean a link for communication from an AP STA to a non-AP STA, and a DL PPDU / packet / signal can be transmitted and received through the DL. In the DL communication, a transmitter can be a part of the AP STA, and a receiver can be a part of the non-AP STA. An uplink (UL) can mean a link for communication from a non-AP STA to an AP STA, and a UL PPDU / packet / signal can be transmitted and received through the UL. In the UL communication, a transmitter can be a part of the non-AP STA, and a receiver can be a part of the AP STA.

[0047] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0048] The structure of the wireless LAN system can be composed of a plurality of components. The wireless LAN supporting mobility transparent to an upper layer can be provided through the interaction of the plurality of components. A basic service set (BSS) corresponds to a basic building block of the wireless LAN. Figure 2 Exemplarily, it is shown that there are two BSSs (BSS1 and BSS2), and two STAs (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2) are included as members of each BSS. Figure 2 ​The ellipse representing the BSS can also be understood to represent a coverage area in which the STAs included in the corresponding BSS maintain communication. This area can be referred to as a basic service area (BSA). When a STA moves outside the BSA, it cannot directly communicate with other STAs within the BSA.

[0049] If the DS shown in FIG. 1 is not considered Figure 2 The most basic BSS type in a wireless LAN is an independent BSS (IBSS) if the DS shown in FIG. 1 is not considered. For example, an IBSS can have a minimum form including only two STAs. For example, assuming that other components are omitted, a BSS 1 including only STA 1 and STA 2 or a BSS 2 including only STA 3 and STA 4 can correspond to representative examples of an IBSS, respectively. This configuration is possible when STAs can directly communicate without an AP. In addition, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since the IBSS does not include an AP, there is no centralized management entity. That is, in the IBSS, STAs are managed in a distributed manner. In the IBSS, all STAs can consist of mobile STAs, and access to a distribution system (DS) is not allowed, thereby forming a self-contained network.

[0050] Membership of STAs in a BSS can be dynamically changed by turning on or off the STAs, entering or exiting the BSS area, etc. In order to become a member of a BSS, a STA can join the BSS using a synchronization process. In order to access all services of the BSS infrastructure, a STA should be associated with the BSS. The association can be dynamically established, and can include use of a distribution system service (DSS).

[0051] A direct STA-to-STA distance in a wireless LAN can be limited by PHY performance. In some cases, this distance limitation can be sufficient, but in some cases, communication between STAs at a longer distance can be required. A distribution system (DS) can be configured to support extended coverage.

[0052] The DS means a structure for interconnecting BSSs. Specifically, as Figure 2As shown, the BSS can exist as an extended form of a network composed of a plurality of BSSs. The DS is a logical concept, and can be specified by the characteristics of a distributed system medium (DSM). In this regard, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for a different purpose, and is used by a different component. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of the wireless LAN structure (DS structure or other network structure) can be interpreted as the plurality of media being logically different. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be independently specified by the physical characteristics of each implementation.

[0053] The DS can support mobile devices by providing seamless integration of a plurality of BSSs and providing logical services necessary for addressing addresses leading to destinations. In addition, the DS can also include a component called a portal, which is used as a bridge for a connection between the wireless LAN and other networks (for example, IEEE 802.X).

[0054] The AP enables access to the DS through the WM for an associated non-AP STA, and means an entity that also has the function of a STA. Data movement between the BSS and the DS can be performed through the AP. For example, Figure 2 The STAs 2 and 3 shown in FIG. 1 have the function of a STA, and provide a function that allows an associated non-AP STA (STAs 1 and 4) to access the DS. In addition, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP to communicate on the WM is not necessarily the same as the address used by the AP to communicate on the DSM. A BSS composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0055] Data transmitted from one of the STAs associated with the AP to the STA address of the corresponding AP can always be received at an uncontrolled port, and can be processed by an IEEE 802.1X port access entity. In addition, when the controlled port is authenticated, the transmitted data (or frame) can be delivered to the DS.

[0056] In addition to the structure of the DS described above, an extended service set (ESS) can also be configured to provide a wide coverage range.

[0057] The ESS means a network composed of DSs and BSSs with arbitrary size and complexity. The ESS can correspond to a set of BSSs connected to one DS. However, the ESS does not include the DS. The ESS network is characterized as IBSS in the logical link control (LLC) layer. STAs included in the ESS can communicate with each other, and a mobile STA can move from one BSS to another BSS (within the same ESS) transparently to the LLC. The APs included in one ESS can have the same service set identification (SSID). The SSID is distinguished from the BSSID which is an identifier of the BSS.

[0058] The wireless LAN system does not assume anything about the relative physical locations of BSSs, and all of the following forms are possible. The BSSs can partially overlap, which is a form commonly used to provide continuous coverage. In addition, the BSSs can not be physically connected, and logically, there is no limit to the distance between the BSSs. In addition, the BSSs can be physically located at the same place, which can be used to provide redundancy. In addition, one (or more than one) IBSS or ESS network can physically exist in the same space as one (or more than one) ESS network. This can correspond to a form of the ESS network when an ad hoc network operates in a place where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same place, or the like.

[0059] Figure 3 is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0060] In order for a STA to establish a link with respect to a network and transmit / receive data, it first discovers the network, performs authentication, establishes association, and needs to perform an authentication process for security. The link establishment process can also be referred to as a session initiation process or a session establishment process. In addition, the discovery, authentication, association, and security establishment processes of the link establishment process can be collectively referred to as an association process.

[0061] In step S310, the STA can perform a network discovery operation. The network discovery operation can include a scanning operation of the STA. That is, in order for the STA to access a network, it needs to find a network that it can participate in. The STA should identify a compatible network before participating in a wireless network, and the process of identifying a network present in a specific area is referred to as scanning.

[0062] The scanning scheme includes active scanning and passive scanning. Figure 3A network discovery operation including an active scan process is exemplarily illustrated. In the active scan, the STA performing the scan transmits a probe request frame to discover what APs exist around it while the channel moves and waits for a response thereto. The responder transmits a probe response frame as a response to the probe request frame to the STA having transmitted the probe request frame. Here, the responder can be the STA which last transmitted a beacon frame in the BSS of the channel being scanned. In the BSS, since the AP transmits the beacon frame, the AP becomes the responder, and in the IBSS, the STAs in the IBSS rotate to transmit the beacon frame, so the responder is not constant. For example, the STA which transmits the probe request frame on channel 1 and receives the probe response frame on channel 1 can store the BSS-related information included in the received probe response frame, and can move to the next channel (e.g., channel 2) and perform the scan in the same manner (i.e., transmission and reception of the probe request / response on channel 2).

[0063] Although not shown in Figure 3 , a scan operation can be performed in a passive scan manner. In the passive scan, the STA performing the scan waits for a beacon frame while the channel moves. The beacon frame is one of the management frames defined in IEEE 802.11, and is periodically transmitted to notify of the existence of a wireless network, and to allow the STA performing the scan to find the wireless network and participate in the wireless network. In the BSS, the AP is used to periodically transmit the beacon frame, and in the IBSS, the STAs within the IBSS rotate to transmit the beacon frame. When the STA performing the scan receives the beacon frame, the STA stores the information of the BSS included in the beacon frame, and records the beacon frame information in each channel while moving to another channel. The STA receiving the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform the scan in the next channel in the same manner. Comparing the active scan with the passive scan, the active scan has an advantage in that it has less delay and less power consumption than the passive scan.

[0064] After the STA discovers the network, an authentication process can be performed at step S320. In order to clearly distinguish from a security establishment operation of step S340 which will be described later, the authentication process can be referred to as a first authentication process.

[0065] The authentication process includes a process in which the STA transmits an authentication request frame to the AP, and in response thereto, the AP transmits an authentication response frame to the STA. The authentication frame for the authentication request / response corresponds to a management frame.

[0066] The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), and a finite cyclic group, and the like. This corresponds to some examples of information that can be included in an authentication request / response frame, and can be replaced with other information, or additional information can also be included.

[0067] The STA can transmit an authentication request frame to the AP. The AP can determine whether to allow authentication of the corresponding STA based on information included in the received authentication request frame. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0068] After the STA is successfully authenticated, an association process can be performed at step S330. The association process includes the following processing: the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA.

[0069] For example, the association request frame can include information related to 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 (TIM broadcast request), interworking service capabilities, and the like. For example, the association response frame can include information related to various capabilities, a status code, an association ID (AID), supported rates, an enhanced distributed channel access (EDCA) parameter set, a received channel power indicator (RCPI), a received signal to noise indicator (RSNI), a mobility domain, a super interval (e.g., an association recovery time), an overlapping BSS scan parameter, a TIM broadcast response, a quality of service (QoS) map, and the like. This corresponds to some examples of information that can be included in an association request / response frame, and can be replaced with other information, or additional information can also be included.

[0070] After the STA is successfully associated with the network, a security establishment process can be performed at step S340. The security establishment process of step S340 can be referred to as an authentication process through a robust security network association (RSNA) request / response, the authentication process of step S320 is referred to as a first authentication process, and the security establishment process of step S340 can also be simply referred to as an authentication process.

[0071] The security establishment process of step S340 can include, for example, a process of establishing a private key through an extensible authentication protocol over LAN (EAPOL) frame using a four-way handshake. In addition, the security establishment process can be performed according to a security scheme that is not defined in the IEEE 802.11 standard.

[0072] Figure 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0073] In a wireless LAN system, a basic access mechanism of a medium access control (MAC) is a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also referred to as a distributed coordination function (DCF) of IEEE 802.11 MAC, and basically adopts a "listen before talk" access mechanism. According to this type of access mechanism, an AP and / or a STA can perform an explicit channel assessment (CCA) of sensing a wireless channel or medium during a predetermined time interval (e.g., a DCF interframe space (DIFS)) before starting transmission. As a result of sensing, if it is determined that the medium is in an idle state, a frame transmission is started by the corresponding medium. On the other hand, if it is detected that the medium is occupied or busy, the corresponding AP and / or STA does not start its own transmission, and can set a delay period (e.g., a random backoff period) for medium access and attempt frame transmission after waiting. By applying the random backoff period, since a plurality of STAs are expected to attempt frame transmission after waiting for different time periods, a collision can be minimized.

[0074] In addition, the IEEE 802.11 MAC protocol provides a hybrid coordination function (HCF). The HCF is based on the DCF and a point coordination function (PCF). The PCF is a polling-based synchronous access method, and refers to a method in which all receiving APs and / or STAs are periodically polled to receive data frames. In addition, the HCF has an enhanced distributed channel access (EDCA) and an HCF controlled channel access (HCCA). The EDCA is a contention-based access method that provides data frames to a plurality of users, and the HCCA uses a non-contention-based channel access method using a polling mechanism. In addition, the HCF includes a medium access mechanism for improving QoS (quality of service) of a wireless LAN, and can transmit QoS data in a contention period (CP) and a contention free period (CFP).

[0075] Referring to Figure 4An operation based on a random backoff period will be described. When the occupied / busy medium becomes an idle state, a plurality of STAs can attempt to transmit data (or a frame). As a method of minimizing collisions, each of the STAs can respectively select a random backoff count, and attempt transmission after waiting for a corresponding slot time. The random backoff count has a pseudo-random integer value, and can be determined as one of values ranging from 0 to CW. Here, CW is a contention window parameter value. The CW parameter is given a CWmin as an initial value, but can take a value twice as large in the case of transmission failure (for example, when an ACK is not received for a transmitted frame). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and when data transmission is successful, the CWmin value is reset. The values of CW, CWmin, and CWmax are preferably set to 2n-1 (n=0, 1, 2,...).

[0076] When the random backoff process starts, the STA continuously monitors the medium according to the determined backoff count value for the backoff slot countdown. When monitoring the medium for occupation, it stops the countdown and waits, and when the medium becomes idle, it restarts the remaining portion of the countdown.

[0077] In the example of FIG. 3, Figure 4 When a packet to be transmitted arrives at the MAC of STA 3, STA 3 can transmit a frame immediately after confirming that the medium is idle for DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. Meanwhile, data to be transmitted can also occur in each of STA 1, STA 2, and STA 5, and when the medium is monitored to be idle, each STA waits for DIFS, and then can perform countdown of a backoff slot according to a random backoff count value selected by each STA. It is assumed that STA 2 selects the minimum backoff count value, and STA 1 selects the maximum backoff count value. That is, a case is exemplified in which the remaining backoff time of STA 5 is shorter than that of STA 1 when STA 2 completes the backoff count and starts frame transmission. STA 1 and STA 5 temporarily stop the countdown, and wait while STA 2 occupies the medium. When the occupation of STA 2 ends and the medium becomes idle again, STA 1 and STA 5 wait for DIFS and restart the stopped backoff count. That is, frame transmission can start after countdown of the remaining backoff slot for the remaining backoff time. Since the remaining backoff time of STA 5 is shorter than that of STA 1, STA 5 starts frame transmission. Data to be transmitted can also occur in STA 4 while STA 2 occupies the medium. From the perspective of STA 4, when the medium becomes idle, STA 4 can wait for DIFS, and then can perform countdown according to a random backoff count value selected by STA 4, and start transmitting a frame. Figure 4The example shows a situation where STA5's remaining backoff time accidentally conflicts with STA4's random backoff count value. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, and data transmission fails. In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. While the medium is occupied by STA4 and STA5's transmissions, STA1 waits. When the medium becomes idle, STA1 waits DIFS and then begins frame transmission after the remaining backoff time has elapsed.

[0078] As in Figure 4 In the example, a data frame is a frame used to transmit data forwarded to a higher layer and can be transmitted after a backoff is performed after a DIFS period has elapsed since the medium became idle. Furthermore, a management frame is a frame used to exchange management information that is not forwarded to a higher layer and is transmitted after a backoff is performed after an IFS period, such as a DIFS period or a Point Coordination Function (PIFS). Subtypes of management frames include beacons, association requests / responses, reassociation requests / responses, probe requests / responses, and authentication requests / responses. Control frames are frames used to control access to the medium. Subtypes of control frames include request to send (RTS), clear to send (CTS), acknowledgement (ACK), power save poll (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), null data packet announcement (NDP announcement), and triggers. If a control frame is not a response frame to the previous frame, it is transmitted after a backoff is performed after a DIFS period has elapsed. If it is a response frame to the previous frame, it is transmitted without a backoff after a short IFS period (SIFS). The type and subtype of a frame may be identified by the type field and subtype field in the frame control (FC) field.

[0079] A Quality of Service (QoS) STA can perform a backoff after the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs (i.e., AIFS (where i is a value determined by the AC)) and then transmit the frame. Here, frames that can use AIFS may be data frames, management frames, or control frames, rather than response frames.

[0080] Figure 5 is a diagram for explaining a frame transmission operation based on CSMA / CA to which the present disclosure can be applied.

[0081] As described above, in addition to the physical carrier sensing in which the STA directly senses the medium, the CSMA / CA mechanism includes virtual carrier sensing. The virtual carrier sensing aims to compensate for problems that can occur in medium access such as the hidden node problem. For the virtual carrier sensing, the MAC of the STA can use a network allocation vector (NAV). The NAV is a value indicating to other STAs the remaining time until the medium is available for use by the currently using or entitled STA. Thus, the value set to the NAV corresponds to the period for which the STA transmitting the frame plans to use the medium, and during the corresponding period, the STA receiving the NAV value is prohibited from accessing the medium. The NAV can be configured, for example, based on the value of the "Duration" field of the MAC header of the frame.

[0082] In Figure 5 the example, it is assumed that STA1 intends to transmit data to STA2, and STA3 is in a position capable of overhearing some or all of the frames transmitted and received between STA1 and STA2.

[0083] To reduce the likelihood of transmission collision of multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames can be applied. In Figure 5 the example, when the transmission of STA1 is being performed, it can be determined that the medium is in an idle state as a result of the carrier sensing of STA3. That is, STA1 can correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 the example, it can be determined that the medium is in an idle state as a result of the carrier sensing of STA3 when the transmission of STA2 is being performed. That is, STA2 can correspond to a hidden node with respect to STA3. By exchanging the RTS / CTS frames before the data transmission and reception between STA1 and STA2, STAs outside the transmission range of one of STA1 or STA2 or STAs outside the carrier sensing range of the transmission of STA1 or STA3 can not attempt to occupy the channel during the data transmission and reception between STA1 and STA2.

[0084] Specifically, STA1 can determine whether the channel is being used through carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy level or signal correlation detected in the channel. In addition, in terms of virtual carrier sensing, STA1 can determine the channel occupancy state using a network allocation vector (NAV) timer.

[0085] When the channel is in an idle state during DIFS, STA1 can transmit an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 can transmit a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0086] If the STA 3 cannot eavesdrop on the CTS frame from the STA 2 but can eavesdrop on the RTS frame from the STA 1, the STA 3 can set the NAV timer for the frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) thereafter using the duration information included in the RTS frame. Alternatively, if the STA 3 can eavesdrop on the CTS frame from the STA 2, the STA 3 can set the NAV timer for the frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame) thereafter using the duration information included in the CTS frame, although the STA 3 cannot eavesdrop on the RTS frame from the STA 1. That is, if the STA 3 can eavesdrop on one or more of the RTS frame or the CTS frame from one or more of the STA 1 or the STA 2, the STA 3 can set the NAV accordingly. When the STA 3 receives a new frame before the NAV timer expires, the STA 3 can update the NAV timer using the duration information included in the new frame. The STA 3 does not attempt channel access until the NAV timer expires.

[0087] When the STA 1 receives the CTS frame from the STA 2, the STA 1 can transmit a data frame to the STA 2 after SIFS from the time point at which reception of the CTS frame is completed. When the STA 2 successfully receives the data frame, the STA 2 can transmit an ACK frame to the STA 1 after SIFS as a response to the data frame. When the NAV timer expires, the STA 3 can determine whether the channel is being used through carrier sensing. When the STA 3 determines that the channel is not being used by other terminals during DIFS after the NAV timer expires, the STA 3 can attempt channel access after a contention window (CW) according to random backoff has passed.

[0088] Figure 6 FIG. 1 is a diagram for explaining an example of a frame structure used in a WLAN system to which the disclosure can be applied.

[0089] The PHY layer can prepare a MAC PDU (MPDU) to be transmitted by means of an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when a command requesting the PHY layer to start transmission is received from the MAC layer, the PHY layer switches to a transmission mode, and configures information (e.g., data) provided from the MAC layer in the form of a frame and transmits it. In addition, when the PHY layer detects a valid preamble of a received frame, the PHY layer monitors a header of the preamble, and transmits a command informing the MAC layer of the start of reception of the PHY layer.

[0090] In this way, information transmission / reception in a wireless LAN system is performed in the form of a frame, and for this purpose, a PHY layer protocol data unit (PPDU) format is defined.

[0091] A basic PPDU can include a short training field (STF), a long training field (LTF), a signal (SIG) field, and a data (Data) field. The most basic PPDU format (e.g., non-HT (high throughput)) shown in FIG. 1A can consist of only a legacy-STF (L-STF), a legacy-LTF (L-LTF), a legacy-SIG (L-SIG) field, and a data field. In addition, depending on the type of PPDU format (e.g., HT mixed format PPDU, HT greenfield format PPDU, VHT (very high throughput) PPDU, etc.), an additional (or different type of) 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.)) can be included between the L-SIG field and the data field. Figure 7

[0092] The STF is a signal for signal detection, automatic gain control (AGC), diversity selection, accurate time synchronization, etc., and the LTF is a signal for channel estimation and frequency error estimation. The STF and the LTF can be referred to as signals for synchronization and channel estimation of an OFDM physical layer.

[0093] The SIG field can include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits, and the L-SIG field can include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity check field, and a 6-bit tail field. The RATE field can include information about the modulation and coding rate of data. For example, the 12-bit length field can include information about the length or duration of the PPDU. For example, the value of the 12-bit length field can be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field can be determined as a multiple of 3. For example, for HE PPDUs, the value of the length field can be determined as a multiple of 3+1 or a multiple of 3+2.

[0094] ​The data field can include a SERVICE field, a physical layer service data unit (PSDU), and a PPDU tail bit, and if necessary, a padding bit. Some bits of the SERVICE field can be used for synchronization of a descrambler at a receiving end. The PSDU corresponds to a MAC PDU defined in a MAC layer, and can include data generated / used in an upper layer. The PPDU tail bit can be used to return an encoder to a 0 state. The padding bit can be used to adjust the length of the data field by a predetermined unit.

[0095] The MAC PDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a frame check sequence (FCS). The MAC frame can consist of a MAC PDU and be transmitted / received through a PSDU of a data part of a PPDU format.

[0096] The MAC header includes a frame control field, a duration / ID field, an address field, and the like. The frame control field can include control information required for transmission / reception of a frame. The duration / ID field can be set to a time for transmitting a corresponding frame or the like. For details of sequence control, QoS control, and HT control subfields of the MAC header, refer to IEEE 802.11 standard documents.

[0097] The null data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, the NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and additional non-legacy SIG, non-legacy STF, non-legacy LTF (if present)) of a general PPDU format and does not include a remaining part (i.e., a data field).

[0098] Figure 7 is a diagram illustrating an example of a PPDU defined in an IEEE 802.11 standard to which the disclosure can be applied.

[0099] In standards such as IEEE 802.11a / g / n / ac / ax, various types of PPDUs have been used. A basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and a data field. The basic PPDU format can also be referred to as a non-HT PPDU format (as shown in (a) of Figure 7

[0100] The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields, compared to the basic PPDU format. Figure 7 ​The HT PPDU format shown in (b) can be referred to as the HT mixed format. In addition, an HT greenfield format PPDU can be defined, and this corresponds to a format (not shown) consisting of an HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a data field, excluding L-STF, L-LTF, and L-SIG.

[0101] An example of a VHT PPDU format (IEEE 802.11ac) additionally includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (as shown in (c)) compared to the basic PPDU format. Figure 7

[0102] An example of a HE PPDU format (IEEE 802.11ax) additionally includes a repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, a packet extension (PE) field (as shown in (d)) compared to the basic PPDU format. Some fields can be excluded, or their length can vary depending on the detailed example of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and HE-SIG-B is not included in the HE PPDU format for single-user (SU). In addition, the HE trigger-based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field can vary to 8 μβ. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary to 16 μβ. For example, the RL-SIG can be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, a receiving STA can know that the received PPDU is a HE PPDU or an EHT PPDU, which will be described later. Figure 7

[0103] The EHT PPDU format can include Figure 7 EHT MU (multi-user) in (e) of Figure 7 EHT TB (trigger-based) PPDU in (f) of. The EHT PPDU format is similar to the HE PPDU format in that it includes the RL-SIG following the L-SIG, but can include the U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0104] Figure 7 ​​The EHT MU PPDU in (e) corresponds to a PPDU carrying one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0105] In comparison with the EHT MU PPDU, Figure 7 The EHT TB PPDU in (f) omits the EHT-SIG. The STA receiving the trigger for UL MU transmission (e.g., a trigger frame or a triggered response schedule (TRS)) can perform the UL transmission based on the EHT TB PPDU format.

[0106] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), EHT-SIG fields can be encoded and modulated such that even legacy STAs can attempt to demodulate and decode, and can be mapped based on the determined subcarrier frequency spacing (e.g., 312.5 kHz). These can be referred to as pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, data, PE fields can be encoded and modulated to be demodulated and decoded by STAs that successfully decoded the non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information included in the field, and can be mapped based on the determined subcarrier frequency spacing (e.g., 78.125 kHz). These can be referred to as EHT modulation fields.

[0107] 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. In addition, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields can be referred to as VHT modulation fields.

[0108] The EHT-SIG field included in Figure 7The U-SIG in the EHT PPDU format can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 ps, and the U-SIG can have a total duration of 8 ps. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0109] The U-SIG can be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG can be duplicated. That is, the same 4 U-SIGs can be included in the 80 MHz PPDU. A PPDU that exceeds the 80 MHz bandwidth can include different U-SIGs.

[0110] For example, A unencoded bits can be transmitted through the U-SIG, a first symbol of the U-SIG (e.g., U-SIG-1 symbol) can transmit a first X bits of information out of a total of A bits of information, and a second symbol of the U-SIG (e.g., U-SIG-2 symbol) can transmit a remaining Y bits of information out of the total of A bits of information. The A bits of information (e.g., 52 unencoded bits) can include a CRC field (e.g., 4-bit long field) and a tail field (e.g., 6-bit long field). For example, the tail field can be used to terminate a trellis structure of a convolutional decoder and can be set to 0.

[0111] The bits of information transmitted through the U-SIG can be divided into version-independent bits and version-dependent bits. For example, the U-SIG can be included in a new PPDU format (e.g., UHR PPDU format) not shown in Figure 7 The version-independent bits can be the same, and some or all of the version-dependent bits can be different, 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.

[0112] For example, the size of the version-independent bits of the U-SIG can be fixed or variable. The version-independent bits can be assigned to only the U-SIG-1 symbol, or to both the U-SIG-1 symbol and the U-SIG-2 symbol. The version-independent bits and the version-dependent bits can be referred to by various names, such as first control bits and second control bits.

[0113] For example, the version-independent bits of the U-SIG can include a 3-bit physical layer version identifier (PHY version identifier), and this information can indicate a PHY version (e.g., EHT, UHR, etc.) of a transmitted / received PPDU. The version-independent bits of the U-SIG can include a 1-bit UL / DL flag field. A first value of the 1-bit UL / DL flag field is related to UL communication, and a second value of the UL / DL flag field is related to DL communication. The version-independent bits of the U-SIG can include information on a length of a transmit opportunity (TXOP) and information on a BSS color ID.

[0114] For example, the version-dependent bits of the U-SIG can include information directly or indirectly indicating a type of the PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0115] Information required for PPDU transmission and reception can be included in the U-SIG. For example, the U-SIG can further include information on a bandwidth, information on an MCS technique applied to a non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether a DCM (Dual Carrier Modulation) technique (e.g., a technique for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information on a number of symbols used for the non-legacy SIG, information on whether the non-legacy SIG is generated across the entire frequency band.

[0116] Some of the information required for PPDU transmission and reception can be included in the U-SIG and / or a non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information on a type of a non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information on a length of a non-legacy LTF and a CP (Cyclic Prefix) length, information on a GI (Guard Interval) applicable to a non-legacy LTF, information on preamble puncturing applicable to a PPDU, information on resource unit (RU) allocation, etc. can be included only in the U-SIG, only in the non-legacy SIG, or can be indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0117] Preamble puncturing can denote transmission of a PPDU in which there is no signal in one or more frequency units among a bandwidth of the PPDU. For example, a size of a frequency unit (or resolution of preamble puncturing) can be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing can be applied to a PPDU bandwidth of a predetermined size or more.

[0118] In Figure 7In an example of the HE-SIG-B and the EHT-SIG, a non-legacy SIG such as the HE-SIG-B and the EHT-SIG can include control information for a receiving STA. The non-legacy SIG can be transmitted over at least one symbol, and one symbol can have a length of 4 µs. Information about a number of symbols for the EHT-SIG can be included in a previous SIG (e.g., the HE-SIG-A, the U-SIG, etc.).

[0119] The non-legacy SIG such as the HE-SIG-B and the EHT-SIG can include a common field and a user-specific field. The common field and the user-specific field can be encoded separately.

[0120] In some cases, the common field can be omitted. For example, in a compressed mode in which non-orthogonal frequency division multiple access (OFDMA) is applied, the common field can be omitted, and a plurality of STAs can receive a PPDU (e.g., a data field of the PPDU) through the same frequency band. In a non-compressed mode in which OFDMA is applied, a plurality of users can receive a PPDU (e.g., a data field of the PPDU) through different frequency bands.

[0121] A number of user-specific fields can be determined based on a number of users. One user block field can include up to two user fields. Each user field can be associated with a MU-MIMO allocation, or can be associated with a non-MU-MIMO allocation.

[0122] The common field can include a CRC bit and a tail bit, and a length of the CRC bit can be determined as 4 bits, and a length of the tail bit can be determined as 6 bits and set to 000000. The common field can include RU allocation information. The RU allocation information can include information about locations of RUs to which a plurality of users (i.e., a plurality of receiving STAs) are assigned.

[0123] An RU can include a plurality of subcarriers (or tones). The RU can be used when a signal is transmitted to a plurality of STAs based on an OFDMA technique. In addition, the RU can be defined even when a signal is transmitted to one STA. A non-legacy STF, a non-legacy LTF, and a data field can be allocated resources in units of the RU.

[0124] An RU of an applicable size can be defined according to a PPDU bandwidth. An RU can be defined identically or differently for an applied PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU layout of an HE PPDU and an EHT PPDU can be different. The applicable RU size per PPDU bandwidth, the number and location of RUs, the location and number of DC (direct current) subcarriers, the location and number of null subcarriers, the location and number of guard subcarriers, etc. can be referred to as a tone plan. For example, a tone plan for a high bandwidth can be defined in the form of multiple iterations of a low bandwidth tone plan.

[0125] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2x996-tone RUs, 3x996-tone RUs, etc. An MRU (multi-RU) is different from a plurality of individual RUs and corresponds to a group of subcarriers consisting of a plurality of RUs. For example, one MRU can be defined as 52+26-tone, 106+26-tone, 484+242-tone, 996+484-tone, 996+484+242-tone, 2x996+484-tone, 3x996-tone, or 3x996+484-tone. In addition, the plurality of RUs constituting one MRU can be continuous or can not be continuous in the frequency domain.

[0126] A specific size of an RU can be reduced or expanded. Accordingly, the specific size (i.e., the number of corresponding tones) of each RU in the present disclosure is not restrictive but illustrative. In addition, in the present disclosure, the number of RUs can vary according to the RU size within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz,...).

[0127] Figure 7 The names of each field in the PPDU format of are exemplary, and the scope of the present disclosure is not limited by the names. In addition, examples of the present disclosure can be applied to the PPDU format shown in and a new PPDU format that excludes some fields and / or adds some fields based on the PPDU format of Figure 7 . Resource unit

[0128] Figures 8 to 10

[0129] Figures 8 to 10 is a diagram for explaining an example of a resource unit of a WLAN system to which the present disclosure can be applied.

[0130] Referring to Figures 8 to 10 ​A resource unit (RU) defined in a wireless LAN system will be described. The RU can include a plurality of subcarriers (or tones). The RU can be used when a signal is transmitted to a plurality of STAs based on an OFDMA scheme. Also, the RU can be defined even when a signal is transmitted to one STA. The RU can be used for a data field of a PPDU, an STF, an LTF, etc.

[0131] As shown in Figure 8 Corresponding to different numbers of tones (i.e., subcarriers), RUs are used to construct some fields of a 20MHz, 40MHz, or 80MHz X-PPDU (X is HE, EHT, etc.). For example, resources can be allocated in the RU units shown for X-STF, X-LTF, and a data field.

[0132] Figure 8 is a diagram illustrating an exemplary allocation of resource units (RUs) used on a 20MHz band.

[0133] As shown at the top of Figure 8 26-units (i.e., units corresponding to 26 tones) can be allocated. 6 tones can be used as a guard band in the leftmost band of the 20MHz band, and 5 tones can be used as a guard band in the rightmost band of the 20MHz band. Also, 7 DC tones are inserted in the center band (that is, the DC band), and 26-units corresponding to each of the 13 tones can exist on the left and right of the DC band. Also, 26-units, 52-units, and 106-units can be allocated to other bands. Each unit can be allocated to a STA or a user.

[0134] Figure 8 The RU allocation of Figure 8 The RU allocation of

[0135] In the example of Figure 9 In the example of Figure 10 and / or Figure 8In the example, the fact that the size and / or number of RUs can vary is related to Figure 9 Same as the example.

[0136] Figure 8 is a diagram illustrating an exemplary allocation of resource units (RUs) used on a 40 MHz frequency band.

[0137] As in Figure 9 As in the example using various RU sizes, you can also Figure 10 In the example of , 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. are used. In addition, 5 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.

[0138] Additionally, as shown, when used for a single user, 484-RU may be used.

[0139] Figure 8 is a diagram illustrating an exemplary allocation of resource units (RUs) used on an 80 MHz frequency band.

[0140] As in Figure 9 and Figure 10 As in the example using various RU sizes, you can also Figure 10 In the example of , 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc. are used. In addition, in the case of 80MHz PPDU, the RU allocation of HE PPDU and EHT PPDU can be different, and Figure 10 The example of FIG. 1 shows an example of RU allocation for an 80 MHz EHT PPDU. Figure 10 The scheme in which 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 is the same in the HE PPDU and EHT PPDU. Unlike the HE PPDU, in which 7 DC tones are inserted in the DC band and one 26-RU corresponding to each of the 13 tones exists on the left and right sides of the DC band, in the EHT PPDU, 23 DC tones are inserted in the DC band and one 26-RU exists on the left and right sides of the DC band. Unlike the HE PPDU, in which one null subcarrier exists between 242-RUs instead of in the center band, the EHT PPDU has five null subcarriers. In the HE PPDU, one 484-RU does not include any null subcarriers, but in the EHT PPDU, one 484-RU includes five null subcarriers.

[0141] In addition, as illustrated, 996-RU can be used when used for single user, and in this case, 5 DC tones are inserted as with HE PPDU and EHT PPDU.

[0142] In Figure 10 , an EHT PPDU on 160 MHz can be configured with multiple 80 MHz sub-blocks. RU allocation for each 80 MHz sub-block can be the same as that of an 80 MHz EHT PPDU of Figure 10 . If an 80 MHz sub-block of a 160 MHz or 320 MHz EHT PPDU is not punctured and the entire 80 MHz sub-block is used as part of an RU or multiple RUs (MRU), the 80 MHz sub-block can use Distributed resource unit 996-RU of

[0143] Here, the MRU corresponds to a group of subcarriers (or tones) consisting of multiple RUs, and the multiple RUs constituting the MRU can be RUs having the same size or RUs having different sizes. For example, a single MRU can be defined as 52+26-tone, 106+26-tone, 484+242-tone, 996+484-tone, 996+484+242-tone, 2x996+484-tone, 3x996-tone, or 3x996+484-tone. Here, the multiple RUs constituting one MRU can correspond to small size (e.g., 26, 52, or 106) RUs or large size (e.g., 242, 484, or 996) RUs. That is, one MRU including small size RUs and large size RUs can not be configured / defined. In addition, the multiple RUs constituting one MRU can be continuous in the frequency domain, or can not be continuous.

[0144] When the 80 MHz sub-block includes an RU smaller than 996 tones or a part of the 80 MHz sub-block is punctured, the 80 MHz sub-block can use an RU allocation other than the 996-tone RU.

[0145] The RU of the present disclosure can be used for uplink (UL) and / or downlink (DL) communication. For example, when trigger-based UL-MU communication is performed, the STA that sends the trigger (e.g., the AP) can allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the first STA through trigger information (e.g., a trigger frame or a trigger response schedule (TRS)) and allocate a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the second STA. Thereafter, the first STA can send a first trigger-based (TB) PPDU based on the first RU, and the second STA can send a second TB PPDU based on the second RU. The first / second TB PPDUs can be sent to the AP within the same time period.

[0146] For example, when configuring a DL MU PPDU, the STA (e.g., AP) transmitting the DL MU PPDU may allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the second STA. In other words, the transmitting STA (e.g., AP) may transmit the X-STF (e.g., X is HE, EHT, etc.), X-LTF, and data fields for the first STA via the first RU within a MU PPDU, and may transmit the X-STF, X-LTF, and data fields for the second STA via the second RU. Information regarding the RU arrangement may be signaled via the X-SIG (e.g., X is HE, EHT, U) field in the X-PPDU format.

[0147] Figure 11

[0148] Due to regulations in various regions, power spectral density (PSD) limits may apply in frequency bands below 7 GHz (e.g., 6 GHz). For non-AP STAs in the low-power indoor (LPI) band, 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.

[0149] Furthermore, different 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. For existing 52-tone RUs, the maximum Tx power may be approximately 17 dBm. If PSD limits can be avoided in the 5 GHz band, the transmit power can be increased. For example, the maximum transmit power for existing 52-tone RUs is 24 dBm, which is still 6 dBm lower than the maximum allowed effective isotropically radiated power of 30 dBm.

[0150] When the PSD limit is overcome, the transmission power can be increased, thereby improving spectral efficiency or extending range.

[0151] Considering that the PSD limit is defined per MHz for each STA, when the tones of a small RU are distributed over a wide bandwidth, the tones for each STA are non-continuous, and thus each tone can be transmitted with high power. An RU including tones distributed in this manner is referred to as a distributed RU (DRU), and in order to distinguish it, an RU including continuous tones defined in existing WLAN systems (e.g., systems according to IEEE 802.11ax, 11be, etc.) can be referred to as a regular RU (RRU).

[0152] A STA transmitting a DRU can use high power compared to a STA transmitting an existing RRU. For example, a 52-tone DRU across 80 MHz has only one tone per MHz, whereas for a 52-tone RRU, there are approximately 13 tones per MHz. When a PSD limit of -1 dBm / MHz is assumed in a 6 GHz LPI band, for a 52-tone RU, the transmission power can be increased by approximately 11 dB when using a DRU. When the transmission power is increased in this manner, a higher MCS can be applied and a longer range can be supported.

[0153] Figure 11 is a diagram for explaining an example in which a DRU of the disclosure can be applied.

[0154] 20 MHz bandwidth An example of illustrates that STA1 performs transmission on DRU1, STA2 performs transmission on DRU2, and STA3 performs transmission on DRU3. Each STA can apply a transmission power boost by using a DRU. Higher transmission power is applied to all tones in the DRU compared to when the same size RRU is used, and thus spectral efficiency can be greatly improved. In this way, a DRU can be usefully applied, in particular, in UL OFDMA.

[0155] In the case of an AP, a DRU can also be utilized. In some cases, the AP can perform DL-OFDMA transmission to STAs by using only some of DRU1, DRU2, and DRU3, and in this case, a transmission power boost due to the use of a DRU can be applied.

[0156] To maximize the power boost, the tones within a DRU can be distributed as far apart as possible. For example, a DRU that includes one tone per MHz can be considered a preferred example. The size of the DRU (or the number of usable tones included in one DRU (i.e., the number of remaining tones excluding unusable tones such as null tones, guard tones, DC tones, etc.)) can be defined to be the same as the size of the RRU (or the number of usable tones included in one RRU). Thus, the impact on various techniques previously defined based on RRU can be minimized. The table below shows an example of achievable power boost (in dB) for various DRUs distributed over different bandwidths. The example in the table below assumes a 6 GHz LPI band, and power boost can also be obtained in the 2.4 GHz band and 5 GHz band in other regions. For example, in an 80 MHz UL-OFDMA transmission by 8 users, when each user uses a 106-tone DRU, the overall performance can be boosted by approximately 8.13 dB compared to when each user uses a 106-tone RRU. In this way, DRUs can be used to overcome PSD limitations and obtain significant benefits.

[0157] [Table 1]

[0158] 40 MHz bandwidth 80 MHz bandwidth 26-tone RU 52-tone RU 8.13 11.14 11.14 106-tone RU 6.37 8.13 11.14 242-tone RU 3.36 6.37 8.13 Not applicable 484-tone RU 2.69 5.12 Not applicable Not applicable Trigger frame 2.69

[0159] Figure 12

[0160] Figure 12 is a diagram representing an example format of a trigger frame to which the present disclosure can be applied.

[0161] The trigger frame can allocate resources and request TB PPDU transmission for at least one TB PPDU. The trigger frame can also include other information required for STAs to transmit the TB PPDU in response thereto. The trigger frame can include a common info and a user info list field in a frame body.

[0162] The common info field can include information commonly applied to at least one TB PPDU transmission requested by the trigger frame, for example, a trigger type, an UL length, whether there is a subsequent trigger frame (e.g., more TF), whether channel sensing (CS) is required, an UL bandwidth (BW), etc. Figure 12 An EHT variant common info field format is exemplarily shown.

[0163] The 4-bit size Trigger Type subfield can have values of 0-15. Among them, values 0, 1, 2, 3, 4, 5, 6, and 7 of the Trigger Type subfield are defined to correspond to Basic, BFRP (Beamforming Report Poll), MU-BAR (Multi-User-Block Ack Request), MU-RTS (Multi-User-Request to Send), BSRP (Buffer Status Report Poll), GCR (Groupcast with Retries) MU-BAR, BQRP (Bandwidth Query Report Poll), and NFRP (NDP Feedback Report Poll), and values 8-15 are defined to be reserved.

[0164] Among the common information, the Trigger-related Common Information subfield can include information selectively included based on the Trigger Type.

[0165] A Special User Info field can 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.

[0166] The User Info List includes at least 0 User Info fields. Transmission and reception based on DRU tone plan An EHT variant User Info field format is exemplarily shown.

[0167] The AID12 subfield basically indicates that it is a User Info field for a STA having a corresponding AID. In addition, when the AID12 field has a predetermined specific value, it can be used for other purposes, such as allocating a Random Access (RA)-RU or configuring in the form of a Special User Info field. The Special User Info field is a User Info field that does not include user-specific information but includes extended common information not provided in the common information field. For example, the Special User Info field can be identified by an AID12 value 2007, and a Special User Info field flag subfield in the common information field can indicate whether the Special User Info field is included.

[0168] The RU Allocation subfield can indicate the size and location of the RU / MRU. For this purpose, the RU Allocation subfield can be interpreted together with the PS160 (Primary / Secondary 160 MHz) subfield of the User Info field, the UL BW subfield of the common information field, etc.

[0169] For example, as in Table 2 below, the mapping of B7-B1 of the RU Allocation subfield can be defined together with the settings of B0 and the PS160 subfield of the User Info field. Table 2 shows an example of the encoding of the PS160 subfield of the EHT variant User Info field and the RU Allocation subfield.

[0170] [Table 2]

[0171]

[0172]

[0173] When B0 of the RU allocation subfield is set to 0, it can indicate that RU / MRU allocation is applied to the primary 80 MHz channel, and when the value is set to 1, it can indicate that RU allocation is applied 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 RU / MRU allocation is applied to the low 80 MHz of the secondary 160 MHz, and when the value is set to 1, it can indicate that RU allocation is applied to the high 80 MHz of the secondary 160 MHz.

[0174] In the trigger frame RU allocation table of Table 2, the parameter N can be calculated based on the equation N = 2*X1+X0. For a bandwidth less than or equal to 80 MHz, the values of PS160, B0, X0, and X1 can be set to 0. For 160 MHz bandwidth and 320 MHz bandwidth, the values of PS160, B0, X0, and X1 can be set as shown in Table 3. This configuration indicates the absolute frequency order for primary and secondary 80 MHz and 160 MHz channels. The order from left to right indicates the order from low frequency to high frequency. The primary 80 MHz channel is indicated as P80, the secondary 80 MHz channel is indicated as S80, and the secondary 160 MHz channel is indicated as S160.

[0175] [Table 3]

[0176]

[0177] Figure 8

[0178] As described above, in order to overcome the PSD limitation and improve power gain, DRU using distributed tones / subcarriers can be applied instead of RRU using contiguous tones / subcarriers.

[0179] In the present disclosure, the definition of DRU tone plans of various sizes and the transmission / reception method based thereon are described for DRU-based transmission / reception of a PPDU in a bandwidth including a 20 MHz channel.

[0180] The tone plan for a 20 MHz bandwidth can include existing RRU supporting various sizes according to the present disclosure (e.g., Figure 13Examples of the 26-tone DRU and various sizes of DRUs. In a tone plan applied for a DRU, 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 location of each tone / subcarrier in the frequency domain can be defined differently. For example, a tone plan supporting 26-tone, 52-tone, and 106-tone DRUs for a 20MHz bandwidth can be defined, but a 242-tone DRU can not support the tone / subcarrier distribution, so it is not included in the examples of the present disclosure.

[0181] In this regard, specifically, the present disclosure proposes a method of utilizing the existing defined pilot subcarriers (e.g., pilot subcarriers defined in IEEE 802.11be) as when transmitting and receiving based on a DRU tone plan in a bandwidth including a 20MHz channel. That is, in the examples of the present disclosure, it is assumed that the location of the pilot subcarriers in the DRU tone plan for a 20MHz bandwidth is the same as the location of the pilot subcarriers in the RRU tone plan for a 20MHz bandwidth.

[0182] For example, for a 20MHz channel or a 40MHz channel, the indices of the pilot subcarriers transmitted for a 26-tone RRU can be defined as in Table 4, the indices of the pilot subcarriers transmitted for a 52-tone RRU can be defined as in Table 5, the indices of the pilot subcarriers transmitted for a 106-tone RRU can be defined as in Table 6, and the indices of the pilot subcarriers transmitted for a 242-tone RRU can be defined as in Table 7.

[0183] [Table 4]

[0184]

[0185] [Table 5]

[0186]

[0187] [Table 6]

[0188]

[0189] [Table 7]

[0190]

[0191] In addition, in the examples of the present disclosure, it is assumed that the number and location of DC subcarriers, null subcarriers, and guard subcarriers in the DRU tone plan for a 20MHz bandwidth are the same as those in the RRU tone plan for a 20MHz bandwidth.

[0192] For example, among 256 subcarriers within a 20MHz bandwidth, the DC subcarrier can correspond to the middle 7 subcarriers of the 20MHz bandwidth, and the guard subcarriers can correspond to the leftmost 6 subcarriers and the rightmost 5 subcarriers of the 20MHz bandwidth. The null subcarriers correspond to four positions (subcarrier indices -122, -69, 69, 122) for 26-tone DRUs and 52-tone DRUs, and for 106-tone DRUs, no null subcarriers are applied (i.e., the four null subcarrier positions considered in 26-tone DRUs and 52-tone DRUs are used as available subcarriers in 106-tone DRUs).

[0193] In the following description, subcarriers within a bandwidth except for DC subcarriers, null subcarriers, guard subcarriers, and pilot subcarriers can be referred to as available subcarriers.

[0194] In the present disclosure, data tone indices in available subcarriers are defined, and a method for selecting pilot subcarriers / tones is proposed.

[0195] In this regard, when a large size DRU tone plan is configured through a combination of small size DRU tone plans, the following scenarios can be assumed to define the indices of data subcarriers: a form before pilot subcarriers are incorporated in the small size DRU tone plans and / or a form before some pilot subcarriers are converted into data subcarriers are combined. At this time, a scenario in which null subcarriers are incorporated into data subcarriers in the small size DRU tone plans can be considered. Thereafter, by defining the indices of pilot subcarriers and considering a scenario in which some pilot subcarriers are changed into data subcarriers, a final DRU, i.e., a DRU tone plan, can be formed / defined.

[0196] Figure 13 FIG. 1 is a diagram for explaining an example of a DRU tone plan-based PPDU reception method of a first STA according to the present disclosure.

[0197] In S1310, the first STA can generate a PPDU including at least one field mapped on at least one DRU.

[0198] For example, the at least one field can include a data field. In other words, a data field of a PPDU can be generated by being mapped on at least one DRU of various sizes.

[0199] If the one or more DRUs include 26-tone DRUs, the 26-tone DRUs can be one of 9 predefined 26-tone DRUs. Here, an nth(n=l, 2,..., 9) 26-tone DRU can include an nth lowest subcarrier among available subcarriers within a 20 MHz channel. Further, the nth(n=l, 2,..., 9) 26-tone DRU can include every 9th subcarrier based on the nth lowest subcarrier.

[0200] In this regard, the available subcarriers can be subcarriers excluding 7 direct current (DC) subcarriers, 4 null subcarriers, 11 guard subcarriers, and 18 pilot subcarriers among 256 subcarriers within the 20 MHz channel.

[0201] For example, a first 26-tone DRU may include subcarrier indices {-121, -111, -101, -92, -82, -72, -61, -52, -42, -32, -23, -13, 4, 14, 24, 33, 43, 53, 63, 73, 83, 93, 103, 112}. A second 26-tone DRU may include subcarrier indices {-120, -110, -100, -91, -81, -71, -60, -51, -41, -31, -21, -12, 5, 15, 25, 34, 44, 54, 64, 74, 84, 94, 104, 113}. A third 26-tone DRU may include subcarrier indices {-119, -109, -99, -89, -80, -70, -59, -50, -40, -30, -20, -11, 6, 16, 26, 35, 45, 55, 65, 75, 85, 95, 105, 114}. A fourth 26-tone DRU may include subcarrier indices {-118, -108, -98, -88, -79, -68, -58, -49, -39, -29, -19, -9, 7, 17, 27, 37, 46, 56, 66, 77, 86, 96, 106, 115}. The fifth 26-tone DRU may include subcarrier indices {-117, -107, -97, -87, -78, -67, -57, -47, -38, -28, -18, -8, 8, 18, 28, 38, 47, 57, 67, 78, 87, 97, 107, 117}. The sixth 26-tone DRU may include subcarrier indices {-115, -106, -96, -86, -77, -66, -56, -46, -37, -27, -17, -7, 9, 19, 29, 39, 49, 58, 68, 79, 88, 98, 108, 118}. The seventh 26-tone DRU may include subcarrier indices {-114, -105, -95, -85, -75, -65, -55, -45, -35, -26, -16, -6, 11, 20, 30, 40, 50, 59, 70, 80, 89, 99, 109, 119}. The eighth 26-tone DRU may include subcarrier indices {-113, -104, -94, -84, -74, -64, -54, -44, -34, -25, -15, -5, 12, 21, 31, 41, 51, 60, 71, 81, 91, 100, 110, 120}. A ninth 26-tone DRU may include subcarrier indices {-112, -103, -93, -83, -73, -63, -53, -43, -33, -24, -14, -4, 13, 23, 32, 42, 52, 61, 72, 82, 92, 101, 111, 121}.

[0202] In this regard, two pilot subcarriers can be allocated for the nth 26-tone DRU. Here, the two pilot subcarriers can correspond to {nth subcarrier index, n+9th subcarrier index} among the subcarrier indices included in the first subcarrier index group {-116, -102, -90, -76, -62, -48, -36, -22, 22, 36, 48, 62, 76, 90, 102, 116} (e.g., pilot subcarrier indices defined for 26-tone RRUs, see Table 4) or the second subcarrier index group {-116, -102, -90, -76, -62, -48, -36, 22, 36, 48, 62, 76, 90, 102, 116} (e.g., pilot subcarrier indices defined for 52-tone RRUs, see Table 5).

[0203] At this time, when a mapping relationship between 9 predefined 26-tone DRUs and 9 26-tone RRUs is defined, the two pilot subcarriers allocated for the nth 26-tone DRU can correspond to two pilot subcarriers defined for a 26-tone RU among the 9 26-tone RRUs mapped to the nth 26-tone DRU. Here, the two pilot subcarriers defined for the 26-tone RU can be one of {-116, -102}, {-90, 76}, {-62, -48}, {-36, -22}, {-10, 10}, {22, 36}, {48, 62}, {76, 90}, or {102, 116}.

[0204] Additionally or alternatively, the two pilot subcarriers can correspond to {nth subcarrier index, n+9th subcarrier index} among the subcarrier indices included in the first subcarrier index group.

[0205] Additionally or alternatively, considering that a first pilot subcarrier index group {-116, -90, -48, -22} is defined for a predefined first 106-tone RU and a second pilot subcarrier index group {22, 48, 90, 116} is defined for a predefined second 106-tone RU (e.g., see Table 6), the pilot subcarriers for the 9 26-tone DRUs can be defined / allocated.

[0206] Specifically, for the first 26-tone DRU to the fourth 26-tone DRU, the subcarrier indices included in the first subcarrier index group and included in the first pilot subcarrier index group (e.g., subcarrier indices {-116, -90, -48, -22}) are each allocated as a pilot subcarrier, and the subcarrier indices included in the first subcarrier index group and used as data subcarriers for the predefined second 106-tone RU (that is, not included in the second pilot subcarrier index group) (e.g., subcarrier indices {36, 62, 76, 102}) are each allocated as a pilot subcarrier. In addition, for the sixth 26-tone DRU to the ninth 26-tone DRU, the subcarrier indices included in the first subcarrier index group and included in the second pilot subcarrier index group (e.g., subcarrier indices {22, 48, 90, 116}) are each allocated as a pilot subcarrier, and the subcarrier indices included in the first subcarrier index group and used as data subcarriers for the predefined first 106-tone RU (that is, not included in the first pilot subcarrier index group) (e.g., subcarrier indices {-102, -76, -62, -36}) are each allocated as a pilot subcarrier. In addition, for the fifth 26-tone DRU, the remaining subcarrier indices included in the first subcarrier index group and not allocated (that is, subcarrier indices not allocated for the first 26-tone DRU to the fourth 26-tone DRU and the sixth 26-tone DRU to the ninth 26-tone DRU) (e.g., subcarrier indices {-10, 10}) can be allocated as pilot subcarriers.

[0207] Based on the at least one DRU including any one of the 52-tone DRUs, the corresponding 52-tone DRU can be one of the 4 predefined 52-tone DRUs.

[0208] For example, the first 52-tone DRU can include subcarriers included in the first 26-tone DRU and the sixth 26-tone DRU. The second 52-tone DRU can include subcarriers included in the second 26-tone DRU and the seventh 26-tone DRU. The third 52-tone DRU can include subcarriers included in the third 26-tone DRU and the eighth 26-tone DRU. The fourth 52-tone DRU can include subcarriers included in the fourth 26-tone DRU and the ninth 26-tone DRU.

[0209] In this regard, four pilot subcarriers can be allocated for each of the four predefined 52-tone DRUs. Here, the four pilot subcarriers can be based on four subcarrier indices included in one of a first subcarrier index set {-116, -102, -90, -76, -62, -48, -36, -22, -10, 10, 22, 36, 48, 62, 76, 90, 102, 116} (e.g., pilot subcarrier indices defined for 26-tone RRUs, see Table 4) or a second subcarrier index set {-116, -102, -90, -76, -62, -48, -36, -22, 22, 36, 48, 62, 76, 90, 102, 116} (e.g., pilot subcarrier indices defined for 52-tone RRUs, see Table 5).

[0210] In this case, when the mapping relationship between the four predefined 52-tone DRUs and the four 52-tone RRUs is defined, the four pilot subcarriers can correspond to the four pilot subcarriers defined for the mapped 52-tone RRUs among the four 52-tone RRUs. Here, the four pilot subcarriers defined for the 52-tone RRUs can be one of pilot subcarrier indices {-116, -102, -90, 76}, {-62, -48, -36, -22}, {22, 36, 48, 62}, or {76, 90, 102, 116}.

[0211] Additionally or alternatively, the four pilot subcarriers can correspond to the four pilot subcarriers allocated for configuring two 26-tone DRUs for the 52-tone DRU.

[0212] Based on the at least one DRU including any one 106-tone DRU, the corresponding 106-tone DRU can be one of 2 predefined 106-tone DRUs.

[0213] For example, a first 106-tone DRU can include a first group corresponding to two of the four null subcarriers, and subcarriers included in the first 52-tone DRU and the third 52-tone DRU. A second 106-tone DRU can include a second group corresponding to the other two of the four null subcarriers, and subcarriers included in the second 52-tone DRU and the fourth 52-tone DRU.

[0214] Here, when indices of the four null subcarriers are -122, -69, 69, and 122, the first group can include subcarrier indices -122 and 69, and the second group can include subcarrier indices -69 and 122. Alternatively, the first group can include subcarrier indices -69 and 122, and the second group can include subcarrier indices -122 and 69.

[0215] In this regard, four pilot subcarriers and four additional data subcarriers may be allocated for each of the two predefined 106-tone RRUs. Here, the four pilot subcarriers and the four additional data subcarriers may be based on eight subcarrier indices included in one of the first subcarrier index group {-116, -102, -90, -76, -62, -48, -36, -22, -10, 10, 22, 36, 48, 62, 76, 90, 102, 116} (e.g., pilot subcarrier indices defined for a 26-tone RRU, see Table 4) or the second subcarrier index group {-116, -102, -90, -76, -62, -48, -36, -22, 22, 36, 48, 62, 76, 90, 102, 116} (e.g., pilot subcarrier indices defined for a 52-tone RRU, see Table 5). At this time, if two pilot subcarrier index groups are defined for the two predefined 106-tone RUs, the indexes of the above four pilot subcarriers may be defined as belonging to at least one of the two pilot subcarrier index groups.

[0216] The DRU tone plans are exemplary, and the tones / subcarriers included in the 26-tone DRU, 52-tone DRU, and 106-tone DRU may be defined according to various other examples described below.

[0217] In S1320 , the first STA may send a PPDU to at least one second STA over a bandwidth including a 20 MHz channel.

[0218] The at least one DRU may be indicated based on RU allocation information included in the corresponding PPDU. For example, the corresponding PPDU may be a downlink PPDU (or DL-OFDMA PPDU).

[0219] Alternatively, at least one DRU may be indicated based on RU allocation information included in a trigger frame that triggers the transmission of a corresponding PPDU. For example, the corresponding PPDU may be a TB PPDU (or an uplink UL-OFDM APPDU).

[0220] Figure 1 The method described in the example can be used by Figure 1 The first device 100 executes. For example, Figure 13 The at least one processor 102 of the first device 100 may be configured to generate a PPDU including at least one field mapped on at least one DRU and transmit the PPDU to at least one second STA over a bandwidth including a 20 MHz channel. In addition, the at least one memory 104 of the first device 100 may store instructions for executing the instructions when executed by the at least one processor 102. Figure 14 Examples or instructions of the methods described in the examples described below.

[0221] Figure 13 is a diagram for explaining an example of a DRU tone plan based PPDU transmission method of a second STA according to the disclosure.

[0222] In S1410, the second STA can receive, from the first STA, a PPDU including at least one field on a bandwidth including a 20 MHz channel.

[0223] In S1420, the second STA can decode the at least one field mapped on the at least one DRU.

[0224] For example, the second STA can determine the number and location of tones / subcarriers of the at least one DRU to which at least one field (e.g., data field) in the PPDU transmitted by the first STA is mapped based on RU allocation information included in the corresponding PPDU or based on RU allocation information included in a trigger frame triggering transmission of the corresponding PPDU. Based on this, the second STA can decode the at least one field mapped to the at least one DRU.

[0225] Various sizes (or numbers of tones / subcarriers) and locations of one or more DRUs, and configuration / definition of pilot subcarriers are described in the examples of Figure 14 are the same as those described in the examples of

[0226] In Figure 1 the examples described in Figure 1 may be performed by the second apparatus 200 in Figure 14 For example, the at least one processor 202 of the second apparatus 200 according to the disclosure can be configured to receive, from the first STA, a PPDU including at least one field on a bandwidth including a 20 MHz channel, and decode the at least one field mapped on the at least one DRU. In addition, the at least one memory 204 of the second apparatus 200 can store instructions for executing the method described in the examples of Figure 13 the examples described in the examples of

[0227] Figure 14 and Figure 13 may correspond to some of various examples of the disclosure. Hereinafter, various examples of the disclosure including Figure 14 and Embodiment 1 will be described in more detail.

[0228] In the embodiments described below, a DRU index (i.e., DRU-n) or nth DRU can correspond to a location in the frequency domain, or can be assigned without considering a location in the frequency domain. In the embodiments described below, for the sake of clarity of description, it is described by assuming that a relatively low DRU index includes a relatively low tone / subcarrier, but the scope of the present disclosure is not limited thereto, and the DRU index can be assigned in various ways to distinguish different DRUs.

[0229] Further, in the following description, a subcarrier index assumes that an index of a DC subcarrier is 0 and corresponds to a location in the frequency domain, and the term subcarrier can be replaced with tone.

[0230] Further, in the following description, an expression a:b:c for a subcarrier index refers to every b subcarrier indices from subcarrier index a to subcarrier index c. Further, in the following description, +-{a:b:c} refers to {-a:b:-c, a:b:c}.

[0231] Embodiment 1-1

[0232] In this embodiment, various examples of subcarrier indices of a 26-tone DRU and a pilot subcarrier related thereto are described.

[0233] Embodiment 1-2

[0234] Embodiment 1-1 describes a method of assigning one subcarrier to each of 9 26-tone DRUs in order from the lowest available subcarrier to the highest available subcarrier. For example, each of the 9 26-tone DRUs can include the following subcarriers.

[0235] 26-tone DRU-1: -121, -111, -101, -92, -82, -72, -61, -52, -42, -32, -23, -13, 4, 14, 24, 33, 43, 53, 63, 73, 83, 93, 103, 112

[0236] 26-tone DRU-2: -120, -110, -100, -91, -81, -71, -60, -51, -41, -31, -21, -12, 5, 15, 25, 34, 44, 54, 64, 74, 84, 94, 104, 113

[0237] 26-tone DRU-3: -119, -109, -99, -89, -80, -70, -59, -50, -40, -30, -20, -11, 6, 16, 26, 35, 45, 55, 65, 75, 85, 95, 105, 114

[0238] 26-tone DRU-4: -118, -108, -98, -88, -79, -68, -58, -49, -39, -29, -19, -9, 7, 17, 27, 37, 46, 56, 66, 77, 86, 96, 106, 115

[0239] 26-tone DRU-5: -117, -107, -97, -87, -78, -67, -57, -47, -38, -28, -18, -8, 8, 18, 28, 38, 47, 57, 67, 78, 87, 97, 107, 117

[0240] 26-tone DRU-6: -115, -106, -96, -86, -77, -66, -56, -46, -37, -27, -17, -7, 9, 19, 29, 39, 49, 58, 68, 79, 88, 98, 108, 118

[0241] 26-tone DRU-7: -114, -105, -95, -85, -75, -65, -55, -45, -35, -26, -16, -6, 11, 20, 30, 40, 50, 59, 70, 80, 89, 99, 109, 119

[0242] 26-tone DRU-8: -113, -104, -94, -84, -74, -64, -54, -44, -34, -25, -15, -5, 12, 21, 31, 41, 51, 60, 71, 81, 91, 100, 110, 120

[0243] 26-tone DRU-9: -112, -103, -93, -83, -73, -63, -53, -43, -33, -24, -14, -4, 13, 23, 32, 42, 52, 61, 72, 82, 92, 101, 111, 121

[0244] Embodiment 1-3

[0245] Implementation 1-2 is a method of assigning one subcarrier to each of 9 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 assigning to the 26-tone DRU including the assigned subcarrier a corresponding subcarrier (i.e., subcarriers with positive indices) that is mirror-symmetric about the assigned subcarrier and the DC subcarrier. For example, each of the 9 26-tone DRUs can include the following subcarriers:

[0246] 26-tone DRU-1: +- {121, 111, 101, 92, 82, 72, 61, 52, 42, 32, 23, 13}

[0247] 26-tone DRU-2: +- {120, 110, 100, 91, 81, 71, 60, 51, 41, 31, 21, 12}

[0248] 26-tone DRU-3: +- {119, 109, 99, 89, 80, 70, 59, 50, 40, 30, 20, 11}

[0249] 26-tone DRU-4: +- {118, 108, 98, 88, 79, 68, 58, 49, 39, 29, 19, 9}

[0250] 26-tone DRU-5: +- {117, 107, 97, 87, 78, 67, 57, 47, 38, 28, 18, 8}

[0251] 26-tone DRU-6: +- {115, 106, 96, 86, 77, 66, 56, 46, 37, 27, 17, 7}

[0252] 26-tone DRU-7: +- {114, 105, 95, 85, 75, 65, 55, 45, 35, 26, 16, 6}

[0253] 26-tone DRU-8: +- {113, 104, 94, 84, 74, 64, 54, 44, 34, 25, 15, 5}

[0254] 26-tone DRU-9: +- {112, 103, 93, 83, 73, 63, 53, 43, 33, 24, 14, 4}

[0255] In the above examples, implementation 1-1 and implementation 1-2 can be advantageous in terms of power gain because they include subcarriers that are uniformly distributed within the DRU. Furthermore, in implementation 1-1, because the spacing between subcarriers within each DRU remains constant compared to implementation 1-2, it can be advantageous in terms of channel estimation performance because of the ease of applying interpolation schemes, etc. Furthermore, implementation 1-2 can provide better performance depending on the application because the subcarrier spacing is symmetric with respect to the DC compared to implementation 1-1.

[0256] In addition to the subcarrier indices included in the 26-tone DRU, such as in the above examples of Embodiment 1-1 and Embodiment 1-2, the subcarrier indices can be allocated to the 26-tone DRU in another way. For example, the above examples assume that the available subcarriers do not include guard subcarriers, null subcarriers, DC subcarriers, and pilot subcarriers, but the subcarrier indices included in each 26-tone DRU can be defined under the assumption that the available subcarriers include one or more of the guard subcarriers, null subcarriers, DC subcarriers, or pilot subcarriers.

[0257] Additionally or alternatively, for a first bandwidth and / or a first BSS color (COLOR), the 26-tone DRU including the subcarrier indices according to the above examples of Embodiment 1-1 and Embodiment 1-2 can be applied, and for a second bandwidth and / or a second BSS color, the 26-tone DRU including the subcarrier indices in another way can be applied.

[0258] Embodiment 2

[0259] Embodiment 1-3 relates to a method for defining pilot subcarriers for a 26-tone DRU (a method based on Embodiment 1-1 or Embodiment 1-2).

[0260] Specifically, a method for allocating 18 pilot subcarriers within a 20MHz bandwidth to 9 26-tone DRUs is proposed. In this regard, for each DRU, two pilot subcarriers can be selected and used among the pilot subcarriers defined in the 26-tone RRU or 52-tone RRU (see, for example, Table 4, Table 5). In this case, the pilot subcarriers between the respective DRUs can not overlap.

[0261] The allocation / definition of the pilot subcarriers for the 26-tone DRU can be based on one or more of the following methods.

[0262] (Method 1)

[0263] Assuming that a mapping relationship between the existing RRU indices and the newly defined DRU indices is predefined, the pilot subcarriers of the DRU can be allocated / defined based on the pilot subcarriers of the RRU mapped to the DRU.

[0264] For example, a DRU can be indicated by reusing an existing signaling method by defining an additional subfield (e.g., information indicating whether it is a DRU, etc.) in an existing RU allocation subfield (e.g., included in a PPDU / trigger frame, etc.). In this case, a DRU can be defined to use the same pilot subcarriers as a RRU mapped through the above mapping relationship. As a specific example, when an xth26-tone RRU within a 20 MHz channel is mapped to a yth26-tone DRU, the pilot subcarrier indices defined for the xth26-tone RRU (e.g., see Table 4) can be assigned to the yth26-tone DRU.

[0265] (Method 2)

[0266] For 9 26-tone DRUs within a 20 MHz channel, a pilot subcarrier having a fixed spacing can be assigned / defined for each 26-tone DRU.

[0267] For example, since there are 18 pilot subcarriers within a 20 MHz channel, two pilot subcarriers spaced by 9 pilot subcarriers can be assigned to each DRU. As a specific example, when the indices of the 18 pilot subcarriers within a 20 MHz channel are set / defined as pilot subcarrier indices 1 through 18, pilot subcarrier indices {1, 10} can be assigned to a 26-tone DRU-1, pilot subcarrier indices {2, 11} can be assigned to a 26-tone DRU-2,..., and pilot subcarrier indices {9, 18} can be assigned to a 26-tone DRU-9.

[0268] (Method 3)

[0269] Considering a case where another size of DRU (e.g., 52-tone DRU, 106-tone DRU) is configured / generated by combining smaller size DRUs (e.g., 26-tone DRU, 52-tone DRU), a pilot subcarrier of each 26-tone DRU within a 20 MHz channel can be assigned / defined.

[0270] For example, for the remaining 8 26-tone DRUs excluding the 26-tone DRU (e.g., 26-tone DRU-5) not used to generate the 52-tone DRU, among the 18 pilot subcarriers, the subcarriers used as pilot subcarriers in the 106-tone RRU can be allocated as pilots for each of the 26-tone DRUs, and the subcarriers used as pilot subcarriers in the 26-tone RRU and / or 52-tone RRU but used as data subcarriers in the 106-tone RRU can be allocated as pilots for each of the 26-tone DRUs. In this case, among the 18 pilot subcarriers, the remaining pilot subcarriers not allocated to the 8 26-tone DRUs can be allocated to the 26-tone DRU not used to generate the 52-tone DRU.

[0271] As a specific example, for the 26-tone DRU-1 to 26-tone DRU-4, the subcarriers used as pilot subcarriers in the 106-tone RRU-1 can be sequentially allocated one by one as pilots, and the subcarriers used as pilot subcarriers in the 26-tone RRU and / or 52-tone RRU but used as data subcarriers in the 106-tone RRU-2 can be sequentially allocated one by one as pilots. Also, for the 26-tone DRU-6 to 26-tone DRU-9, the subcarriers used as pilot subcarriers in the 106-tone RRU-2 can be sequentially allocated one by one as pilots, and the subcarriers used as pilot subcarriers in the 26-tone RRU and / or 52-tone RRU but used as data subcarriers in the 106-tone RRU-1 can be sequentially allocated one by one as pilots. The remaining pilot subcarriers (i.e., among the 18 pilot subcarriers present within the 20 MHz channel, those not allocated to the 26-tone DRU-1 to 26-tone DRU-4 and 26-tone DRU-6 to 26-tone DRU-9) can be allocated to the 26-tone DRU-5.

[0272] Additionally or alternatively, a method of selecting and allocating pilot subcarriers with less or no overlap with STF subcarriers to DRUs with less or no overlap with STF subcarriers can be applied. For example, for the 26-tone DRU-5 in embodiment 1-1, the pilot subcarrier indices {+48, -48} can be allocated.

[0273] Embodiment 2-1

[0274] In this embodiment, various examples of configuring the subcarrier indices of the 52-tone DRU and the pilot subcarriers related thereto will be described.

[0275] Embodiment 2-2

[0276] Embodiment 2-1 relates to a method for configuring one 52-tone DRU by combining two 26-tone DRUs.

[0277] For example, four 52-tone DRUs can be defined within a 20MHz bandwidth, and one 52-tone DRU can correspond to a combination of two 26-tone DRUs. For example, two 26-tone DRUs can correspond to two of the nine 26-tone DRUs defined in Embodiment 1 described above. If 26-tone DRU-5 is not used as a basis for a 52-tone DRU, then a combination of two 26-tone DRUs among the eight 26-tone DRUs can correspond to one 52-tone DRU.

[0278] The two 26-tone DRUs corresponding to one 52-tone DRU can correspond to those DRUs spaced apart as far as possible in the frequency domain and distributing subcarriers uniformly to the 52-tone DRU. Four 52-tone DRUs can be defined as follows.

[0279] 52-tone DRU-1: 26-tone DRU-1 and 26-tone DRU-6

[0280] 52-tone DRU-2: 26-tone DRU-2 and 26-tone DRU-7

[0281] 52-tone DRU-3: 26-tone DRU-3 and 26-tone DRU-8

[0282] 52-tone DRU-4: 26-tone DRU-4 and 26-tone DRU-9

[0283] Here, each 52-tone DRU can be defined as a set of subcarrier indices corresponding to the 26-tone DRU indices defined in Embodiment 1-1 or 1-2.

[0284] Embodiment 3

[0285] Embodiment 2-2 relates to a method for defining pilot subcarriers for 52-tone DRUs (based on the method of Embodiment 2-1).

[0286] Specifically, with respect to the four 52-tone DRUs within a 20MHz bandwidth, four pilot subcarriers can be allocated / defined for each DRU.

[0287] In this regard, for each DRU, four pilot subcarriers can be selected and used among the pilot subcarriers defined in the 26-tone RRU or the 52-tone RRU (see, for example, Table 4, Table 5). In this case, the pilot subcarriers can not overlap between the corresponding DRUs.

[0288] For example, the pilot subcarriers of the 26-tone DRU used in the combination for configuring the 52-tone DRU can be used as the pilot subcarriers of the corresponding 52-tone DRU.

[0289] As another example, similar to the case of the 26-tone DRU, assuming that a mapping relationship between the existing RRU index and the newly defined DRU index is predefined, the pilot subcarriers of the DRU can be allocated / defined based on the pilot subcarriers of the RRU mapped to the DRU. As one example, the DRU can be defined to use the same pilot subcarriers as the pilot subcarriers of the RRU mapped by the above mapping relationship.

[0290] As yet another example, the following method can be applied: selecting and allocating the pilot subcarriers overlapping or having less overlap with the STF subcarriers for the DRU not overlapping or having less overlap with the STF subcarriers.

[0291] Embodiment 3-1

[0292] In this embodiment, various examples of subcarrier indices of the 106-tone DRU and the pilot subcarriers related thereto will be described.

[0293] For example, two 106-tone DRUs can be defined within a 20MHz bandwidth. The subcarrier indices included in one 106-tone DRU can correspond to a set of subcarrier indices included in one of the two 52-tone DRUs and two additional subcarrier indices. Further, the subcarriers included in each 106-tone DRU can be defined to be as distributed as possible.

[0294] Embodiment 3-2

[0295] The two additional subcarriers included in the 106-tone DRU can be two of the four null subcarriers (e.g., -122, -69, 69, 122) not used in the 26-tone DRU and the 52-tone DRU. In other words, some of the null subcarriers in the 26-tone DRU and the 52-tone DRU can be included in the available subcarriers for the 106-tone DRU. Further, the two additional subcarrier indices included in different 106-tone DRUs can not overlap with each other.

[0296] For example, assuming that a mapping relationship between an existing RRU index and a newly defined DRU index is predefined, a 106-tone DRU can be defined to use null subcarriers used in a 106-tone RRU mapped to the 106-tone DRU. That is, in the case where an additional subcarrier index (i.e., a null subcarrier in a 26-tone RRU / DRU or a 52-tone RRU / DRU) is included in a specific 106-tone RRU index, the same additional subcarrier index can be defined to be included in a 106-tone DRU index mapped to the corresponding 106-tone RRU index.

[0297] As another example, among four null subcarriers, two different combinations can be selected so that they do not overlap between different 106-tone DRUs. Specifically, among four null subcarriers (e.g., -122, -69, 69, 122), a combination of odd subcarriers (e.g., {-122, 69}) and a combination of even subcarriers (e.g., {-69, 122}) can be defined to be included in different 106-tone DRUs.

[0298] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-3, and a combination of two null subcarriers.

[0299] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-4, and a combination of two null subcarriers.

[0300] Embodiment 4

[0301] Embodiment 3-2 relates to a method for defining pilot subcarriers for a 106-tone DRU (based on the method of Embodiment 3-1).

[0302] Specifically, with respect to two 106-tone DRUs within a 20 MHz bandwidth, four pilot subcarriers can be allocated / defined for each DRU.

[0303] In this regard, for each DRU, eight pilot subcarriers can be selected from among pilot subcarriers defined in a 26-tone RRU or a 52-tone RRU (see, for example, Table 4, Table 5), of which four can be used as data subcarriers and the remaining four can be used as pilot subcarriers. In this case, when the pilot subcarriers are selected, the four pilot subcarriers and four data subcarriers defined in the 106-tone RRU can be preferably selected.

[0304] For example, among the pilot subcarriers of the 52-tone DRU constituting the 106-tone DRU, the subcarriers defined as data subcarriers in the existing 106-tone RRU can be converted to data subcarriers for the 106-tone DRU, and the subcarriers defined as pilot subcarriers in the existing 106-tone RRU can be used as pilot subcarriers for the 106-tone DRU.

[0305] As another example, assuming that a mapping relationship between the existing RRU index and the newly defined DRU index is predefined, among the subcarriers used in the 106-tone RRU mapped to the 106-tone DRU, the subcarriers that are pilot subcarriers in the 26-tone RRU or the 52-tone RRU but are used as data subcarriers can be included / as data subcarriers for the corresponding 106-tone DRU. In addition, the pilot subcarriers used in the 106-tone RRU mapped to the 106-tone DRU can be pilot subcarriers for the 106-tone DRU.

[0306] As still another example, for a DRU that does not overlap or has less overlap with the STF subcarriers, the pilot subcarriers defined in the 26-tone RRU and / or the 52-tone RRU that overlap with the STF subcarriers can be selected and allocated such that four of them are used as data subcarriers, and the rest are used as pilot subcarriers. In this case, when the pilot subcarriers are selected, the four pilot subcarriers defined in the 106-tone RRU and the four data subcarriers can be preferably selected.

[0307] According to the DRU tone plan defined in the various examples of the present disclosure described above, DRUs of the same / different sizes can be allocated to different STAs.

[0308] For example, when a specific RU index is indicated by an RU allocation field included in a SIG (e.g., U-SIG and / or UHR-SIG) field in a DL OFDMA transmission, the STA receiving the PPDU can interpret that a data field within the corresponding PPDU is mapped on subcarriers included in a DRU corresponding to the indicated RU index, and can decode the data field accordingly. Alternatively, when a specific RU index is indicated by an RU allocation subfield within a trigger frame, the STA receiving the trigger frame can transmit a TB PPDU to which a data field is mapped on subcarriers included in a DRU corresponding to the indicated RU index. Here, the DRU corresponding to the indicated RU index can be determined based on a mapping rule between the RRU and the DRU.

[0309] Embodiment 5

[0310] Instead of pre-defining the 52-tone DRU in Embodiment 2 above to include a fixed combination of two 26-tone DRUs, a method can be applied to dynamically signal to include subcarriers of two 26-tone DRUs in any combination. Here, the 26-tone DRU can be the DRU defined in Embodiment 1, or can be defined in another way.

[0311] Additionally or alternatively, instead of pre-defining the 106-tone DRU in Embodiment 3 to include a fixed combination of two 52-tone DRUs (or a fixed combination of four 26-tone DRUs), a dynamic signaling scheme can be applied to include subcarriers of two 52-tone DRUs in any combination (or four 26-tone DRUs in any combination). Here, the 26-tone DRU / 52-tone DRU can be defined as in Embodiment 1 / Embodiment 2, or can be defined in another way. Furthermore, the combination of the two additional subcarriers included in the 106-tone DRU can be defined as described in Embodiment 3.

[0312] Even when a dynamic signaling scheme as described above is applied, the combination of pilot subcarriers for 26-tone DRUs, pilot subcarriers for 52-tone DRUs, and additional data subcarriers (e.g., four additional data subcarriers) for 106-tone DRUs can be configured based on Embodiment 1, Embodiment 2, and Embodiment 3.

[0313] When per-symbol shifted DRUs are applied to obtain diversity gain (e.g., when the subcarrier index in a particular DRU index included in a first symbol is different from the subcarrier index in the same particular DRU index included in a second symbol), the method for dynamically signaling subcarriers included in 52-tone DRUs and / or 106-tone DRUs in this way can be usefully applied.

[0314] When the DRU index allocated to the STA is signaled by using the existing RU allocation information (e.g., the SIG (e.g., U-SIG and / or UHR-SIG) field for the DL OFDMA PPDU), a predefined mapping rule between the 26-tone RRU index and the 26-tone DRU index can be applied. For example, the mapping rule can map the DRU index-1 including the lowest subcarrier to the RRU-1 including the lowest subcarrier, and map the DRU including the next lowest subcarrier in ascending order of the RRU index. When the RRC to DRU mapping rule is defined in this way, a plurality of 26-tone RRU indexes can be indicated to the STA to allocate the 52-tone DRU or the 106-tone DRU, and thus, the STA can determine the subcarriers included in the 26-tone DRUs included in the 52-tone DRU or the 106-tone DRU allocated to it.

[0315] For example, 2 / 4 26-tone RRU indexes corresponding to 2 / 4 26-tone DRUs corresponding to the 52-tone DRU / 106-tone DRU can be indicated to one STA through the RU allocation information, and the STA ID value included in the user information (e.g., the user field of the U-SIG / UHR-SIG field of the DL OFDMA PPDU (e.g., MU PPDU) or the UHR variant user information field of the trigger frame) corresponding to such 2 / 4 26-tone RRUs can be set to the same value as the ID of the corresponding STA. In addition, information indicating that the DRU is allocated and / or information indicating whether it is the last index among a plurality of 26-tone RRU indexes corresponding to the DRU allocated to the corresponding STA can be defined within the user information (e.g., the user field of the U-SIG / UHR-SIG field of the DL OFDMA PPDU (e.g., MU PPDU) or the UHR variant user information field of the trigger frame).

[0316] Figure 15

[0317] As in Embodiment 2 described above, the predefined 52-tone DRU includes the subcarriers of two 26-tone DRUs in a fixed combination, and as in Embodiment 3 described above, the predefined 106-tone DRU includes the subcarriers of two 52-tone DRUs (or four 26-tone DRUs) in a fixed combination, but the DRU index can be generalized and mapped to each RRU index, thereby flexibly configuring the 26-tone DRU / 52-tone DRU corresponding to a specific 52-tone DRU / 106-tone DRU.

[0318] For example, 26-tone DRU-a / b / c / d / e / f / g / h / i can be defined to correspond to 26-tone DRU-1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 in any manner (e.g., the indices a to i and the indices 1 to 9 are one-to-one corresponding, but the numerical indices corresponding to each letter index are determined in ascending order or in any order). Here, for the positions of the subcarriers included in the 26-tone DRU, the example of embodiment 1 can be applied or another method can be applied. Based on this, 52-tone DRU-a / b / c / d and 106-tone-DRU-a / b can be defined to correspond to the combination of the DRU indices of lower sizes, as in the following examples.

[0319] 52-tone DRU-a: 26-tone DRU-a and 26-tone DRU-f

[0320] 52-tone DRU-b: 26-tone DRU-b and 26-tone DRU-g

[0321] 52-tone DRU-c: 26-tone DRU-c and 26-tone DRU-h

[0322] 52-tone DRU-d = 26-tone DRU-d and 26-tone DRU-i

[0323] 106-tone DRU-a: 52-tone DRU-a, 52-tone DRU-c, and two additional subcarriers

[0324] 106-tone DRU-b: 52-tone DRU-b, 52-tone DRU-d, and two additional subcarriers

[0325] Here, the two additional subcarriers for the 106-tone DRU can be defined as described in embodiment 3.

[0326] Additionally or alternatively, a gap between a plurality of DRU indices of lower sizes corresponding to one DRU index of higher size can be used. The value of the gap can be explicitly signaled to the STA or can be implicitly signaled based on other information (e.g., bandwidth information, BSS color information, etc.) without separate signaling. For example, 52-tone DRU and 106-tone DRU can include the subcarriers of the lower size DRUs as follows.

[0327] 52-tone DRU-a: 26-tone DRU-a, 26-tone DRU-(a+gap)

[0328] 52-tone DRU-b: 26-tone DRU-b, 26-tone DRU-(b+gap)

[0329] 52-tone DRU-c: 26-tone DRU-c, 26-tone DRU-(c+gap)

[0330] 52-tone DRU-d: 26-tone DRU-d, 26-tone DRU-(d+gap)

[0331] 106-tone DRU-a: 52-tone DRU-a, 52-tone DRU-(a+gap), and two additional subcarriers

[0332] 106-tone DRU-b: 52-tone DRU-b, 52-tone DRU-(b+gap), and two additional subcarriers

[0333] Here, the two additional subcarriers for the 106-tone DRU can be defined as described in Embodiment 3.

[0334] In the above examples, the order of the letter indices of the DRUs and the order of the locations in the frequency domain can be irrelevant. Also, even when the letter indices of the DRUs of different sizes are the same, it does not mean that the order within the same size DRU index is the same.

[0335] In the above examples, the value of the gap can have the same / different values for each DRU size. For example, the value of the gap can have independent values for each DRU size, or can have associated values.

[0336] Figure 15 is a diagram for explaining a PPDU transmission and reception procedure between a transmitting STA and a receiving STA according to an embodiment of the disclosure. Some of the steps shown in ​ may be omitted depending on the situation and / or setting. The transmitting apparatus and the receiving STA can be an AP and / or a non-AP STA.

[0337] The transmitting STA can acquire control information related to the above-described tone plan (or RU / DRU) (S105). The control information related to the tone plan can include information for the size and location of the RU, control information related to the RU, information for a frequency band in which the RU is included, and information for a STA that receives the RU.

[0338] The transmitting STA can construct / generate a PPDU based on the acquired control information (S110). The construction / generation of the PPDU can mean the construction / generation of each field of the PPDU. That is, the step of constructing / generating the PPDU can include a step of constructing / configuring an EHT-SIG-A / B / C field including control information for the tone plan.

[0339] That is, the step of constructing / generating the PPDU can include a step of constructing / configuring a field including control information (e.g., an N-bit map) indicating the size / location of the RU and / or a step of constructing / configuring a field including an identifier (e.g., an AID) of the STA receiving the RU.

[0340] In addition, the step of constructing / generating the PPDU can include a step of generating an STF / LTF sequence transmitted through the specific RU. The STF / LTF sequence can be generated based on a preconfigured STF generation sequence / LTF generation sequence.

[0341] In addition, the step of constructing / generating the PPDU can include a step of generating a data field (i.e., MPDU) transmitted through the specific RU.

[0342] The transmitting STA can transmit the constructed / generated PPDU to the receiving STA (S115).

[0343] Specifically, the transmitting STA can perform at least one of a cyclic shift diversity (CSD), a spatial mapping, an inverse discrete Fourier transform (IDFT) / inverse fast Fourier transform (IFFT) operation, and a guard interval (GI) insertion operation.

[0344] The receiving STA can decode the PPDU and acquire control information related to the tone plan (or RU) (S120).

[0345] Specifically, the receiving STA can decode the L-SIG and the EHT-SIG of the PPDU based on the L-STF / LTF and acquire information included in the L-SIG and the EHT-SIG field. Information for various tone plans (i.e., RUs) of the present disclosure can be included in the EHT SIG (EHT-SIG-A / B / C, etc.), and the receiving STA can acquire information for the tone plan (i.e., RU) through the EHT-SIG.

[0346] The receiving STA can decode the remaining portion of the PPDU based on the acquired information for the tone plan (i.e., RU) (S125). For example, the receiving STA can decode the STF / LTF field of the PPDU based on the information for the tone plan (i.e., RU). In addition, the receiving STA can decode the data field of the PPDU based on the information for the tone plan (i.e., RU) and acquire the MPDU included in the data field.

[0347] The receiving STA can also perform a processing operation of delivering the decoded data to a higher layer (e.g., a MAC layer). In addition, when a signal generation is indicated from the higher layer to the PHY layer in response to the data delivered to the higher layer, the receiving STA can perform a subsequent operation.

[0348] Unlike the existing WLAN system in which only the RRU is applied, according to the disclosure, when the application of the DRU is supported, it is possible to improve the efficiency of resource utilization by transmitting / receiving at least one field of the PPDU based on various sizes of the DRU tone plan applicable to the PPDU of the 20 MHz bandwidth.

[0349] The above-described embodiments are combinations of elements and features of the present disclosure in a predetermined form. Each of the elements or features should be considered selectively unless explicitly mentioned otherwise. Each of the elements or features can be implemented in a form not combined with other elements or features. Also, the embodiments of the present disclosure can include a combination of some elements and / or features. The order of operations described in the embodiments of the present disclosure can be changed. Some elements or features of one embodiment can be included in other embodiments, or can be replaced with corresponding elements or features of other embodiments. It is obvious that the embodiments can include a claim not explicitly cited in relation to other claims, or can be included as a new claim by modification after the application.

[0350] It will be apparent to those skilled in the art that the disclosure can be implemented in other specific forms without departing from the essential characteristics of the disclosure. Therefore, the above detailed description should not be construed in a limiting sense on every aspect, but should be considered as illustrative. The scope of the disclosure should be determined by reasonable interpretation of the appended claims, and variations within the scope of the disclosure are included in the scope of the disclosure.

[0351] The scope of the disclosure includes software or machine-executable commands (e.g., operating systems, application programs, firmware, programs, etc.) that perform operations according to the methods of various embodiments in an apparatus or computer, and a non-transitory computer-readable medium that causes the software or commands, etc. to be stored and executable in the apparatus or computer. Commands that can be used to program processing systems to perform the features described in the disclosure can be stored in storage media or computer-readable storage media, and the features described in the disclosure can be implemented by using a computer program product including such storage media. The storage media can include a high-speed random access memory such as a DRAM, SRAM, DDR RAM, or other random access solid state storage device, but is not limited thereto, and it can include a non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory optionally includes one or more storage devices that are located remotely from the processor. The memory, or alternatively the non-volatile memory device in the memory, includes a non-transitory computer-readable storage medium. The features described in the disclosure can be stored in any one of machine-readable media to control the hardware of the processing system, and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms with results from the embodiments of the disclosure. Such software or firmware can include application code, device drivers, operating systems, and execution environments / containers, but is not limited thereto.

[0352] Industrial applicability

[0353] The method proposed by the disclosure is mainly described based on an example applied to an IEEE 802.11-based system (5G system), but can be applied to various WLANs or wireless communication systems other than the IEEE 802.11-based system.

Claims

1. A method performed by a first station (STA) in a wireless local area network (WLAN) system, the method comprising the following steps: generating a physical layer protocol data unit (PPDU) comprising one or more fields, wherein the one or more fields are mapped on one or more distributed resource units (DRUs); as well as sending the PPDU to one or more second STAs over a bandwidth including a 20 MHz channel, wherein, based on the one or more DRUs comprising a 26-tone DRU, the 26-tone DRU is one of nine predefined 26-tone DRUs, wherein the nth 26-tone DRU includes the nth lowest subcarrier among the available subcarriers in the 20 MHz channel and is defined as every 9th subcarrier starting from the nth lowest subcarrier, n=1, 2, ..., 9, and The available subcarriers are subcarriers excluding 7 DC subcarriers, 4 null subcarriers, 11 protection subcarriers and 18 pilot subcarriers from the 256 subcarriers in the 20 MHz channel.

2. The method according to claim 1, wherein Allocate two pilot subcarriers for the nth 26-tone DRU, and The two pilot subcarriers are based on two subcarrier indices included in one of the first subcarrier index group {-116, -102, -90, -76, -62, -48, -36, -22, -10, 10, 22, 36, 48, 62, 76, 90, 102, 116} or the second subcarrier index group {-116, -102, -90, -76, -62, -48, -36, -22, 22, 36, 48, 62, 76, 90, 102, 116}.

3. The method according to claim 2, wherein: Based on defining a mapping relationship between the 9 predefined 26-tone DRUs and the 9 26-tone RUs, The two pilot subcarriers allocated for the nth 26-tone DRU correspond to the two pilot subcarriers defined for the 26-tone RU mapped to the nth 26-tone DRU among the nine 26-tone RUs, and The two pilot subcarriers defined for the 26-tone RU are one of the following pilot subcarrier indices: {-116, -102}, {-90, 76}, {-62, -48}, {-36, -22}, {-10, 10}, {22, 36}, {48, 62}, {76, 90}, or {102, 116}.

4. The method according to claim 2, wherein: The two pilot subcarriers correspond to {nth subcarrier index, (n+9th)th subcarrier index} among the subcarrier indices included in the first subcarrier index group.

5. The method according to claim 2, wherein: Based on defining a first pilot subcarrier index group of {-116, -90, -48, -22} for a predefined first 106-tone RU and defining a second pilot subcarrier index group of {22, 48, 90, 116} for a predefined second 106-tone RU, For the first 26-tone DRU to the fourth 26-tone DRU, Subcarrier indices {-116, -90, -48, -22} included in the first subcarrier index group and included in the first pilot subcarrier index group are each allocated as a pilot subcarrier, and The subcarrier indices {36, 62, 76, 102} included in the first subcarrier index group and used as data subcarriers for the predefined second 106-tone RU are each allocated as a pilot subcarrier, and For the sixth to ninth 26-tone DRUs, The subcarrier indices {22, 48, 90, 116} included in the first subcarrier index group and included in the second pilot subcarrier index group are each allocated as a pilot subcarrier, and The subcarrier indices {-102, -76, -62, -36} included in the first subcarrier index group and used as data subcarriers for the predefined first 106-tone RU are each allocated as a pilot subcarrier, and For the fifth 26-tone DRU, the remaining subcarrier indices included in the first subcarrier index group and not allocated are allocated as pilot subcarriers.

6. The method according to claim 1, wherein The first 26-tone DRU includes subcarrier indices {-121,-111,-101,-92,-82,-72,-61,-52,-42,-32,-23,-13,4,14,24,33,43,53,63,73,83,93,103,112}, The second 26-tone DRU includes subcarrier indices {-120,-110,-100,-91,-81,-71,-60,-51,-41,-31,-21,-12,5,15,25,34,44,54,64,74,84,94,104,113}, The third 26-tone DRU includes subcarrier indices {-119,-109,-99,-89,-80,-70,-59,-50,-40,-30,-20,-11,6,16,26,35,45,55,65,75,85,95,105,114}, The fourth 26-tone DRU includes subcarrier indices {-118,-108,-98,-88,-79,-68,-58,-49,-39,-29,-19,-9,7,17,27,37,46,56,66,77,86,96,106,115}, The fifth 26-tone DRU includes subcarrier indices {-117,-107,-97,-87,-78,-67,-57,-47,-38,-28,-18,-8,8,18,28,38,47,57,67,78,87,97,107,117}, The sixth 26-tone DRU includes subcarrier indices {-115,-106,-96,-86,-77,-66,-56,-46,-37,-27,-17,-7,9,19,29,39,49,58,68,79,88,98,108,118}, The seventh 26-tone DRU includes subcarrier indices {-114,-105,-95,-85,-75,-65,-55,-45,-35,-26,-16,-6,11,20,30,40,50,59,70,80,89,99,109,119}, an eighth 26-tone DRU includes subcarrier indices {-113,-104,-94,-84,-74,-64,-54,-44,-34,-25,-15,-5,12,21,31,41,51,60,71,81,91,100,110,120}, and The ninth 26-tone DRU includes subcarrier indices {-112, -103, -93, -83, -73, -63, -53, -43, -33, -24, -14, -4, 13, 23, 32, 42, 52, 61, 72, 82, 92, 101, 111, 121}.

7. The method according to claim 6, wherein: Based on the one or more DRUs comprising a 52-tone DRU, the 52-tone DRU is one of four predefined 52-tone DRUs, a first 52-tone DRU including subcarriers included in the first 26-tone DRU and the sixth 26-tone DRU, a second 52-tone DRU including subcarriers included in said second 26-tone DRU and said seventh 26-tone DRU, A third 52-tone DRU includes subcarriers included in the third 26-tone DRU and the eighth 26-tone DRU, and The fourth 52-tone DRU includes subcarriers included in the fourth 26-tone DRU and the ninth 26-tone DRU.

8. The method according to claim 7, wherein: Allocate four pilot subcarriers to each of the four predefined 52-tone DRUs, and The four pilot subcarriers are based on four subcarrier indices included in one of the first subcarrier index group {-116, -102, -90, -76, -62, -48, -36, -22, -10, 10, 22, 36, 48, 62, 76, 90, 102, 116} or the second subcarrier index group {-116, -102, -90, -76, -62, -48, -36, -22, 22, 36, 48, 62, 76, 90, 102, 116}.

9. The method according to claim 8, wherein Based on defining a mapping relationship between the four predefined 52-tone DRUs and the four 52-tone RUs, The four pilot subcarriers correspond to the four pilot subcarriers defined for the mapped 52-tone RU among the four 52-tone RUs, and The four pilot subcarriers defined for the 52-tone RU are one of the following pilot subcarrier indices: {-116, -102, -90, 76}, {-62, -48, -36, -22}, {22, 36, 48, 62}, or {76, 90, 102, 116}.

10. The method according to claim 8, wherein The four pilot subcarriers correspond to the four pilot subcarriers allocated for the two 26-tone DRUs used to configure the 52-tone DRU.

11. The method according to claim 7, wherein: Based on the one or more DRUs comprising a 106-tone DRU, the 106-tone DRU being one of two predefined 106-tone DRUs, A first 106-tone DRU includes subcarriers included in the first 52-tone DRU and the third 52-tone DRU, and a first group corresponding to two of the four null subcarriers, and The second 106-tone DRU includes the subcarriers included in the second 52-tone DRU and the fourth 52-tone DRU, and a second group corresponding to two additional null subcarriers of the four null subcarriers.

12. The method according to claim 11, wherein Based on the indexes of the four null subcarriers being -122, -69, 69 and 122, The first group includes subcarrier indices -122 and 69, and the second group includes subcarrier indices -69 and 122, or The first group includes subcarrier indices -69 and 122, and the second group includes subcarrier indices -122 and 69.

13. The method according to claim 11, wherein Allocating four pilot subcarriers and four additional data subcarriers to each of the two predefined 106-tone DRUs, and The four pilot subcarriers and the four additional data subcarriers are based on eight subcarrier indices included in any one of the first subcarrier index group {-116, -102, -90, -76, -62, -48, -36, -22, -10, 10, 22, 36, 48, 62, 76, 90, 102, 116} or the second subcarrier index group {-116, -102, -90, -76, -62, -48, -36, -22, 22, 36, 48, 62, 76, 90, 102, 116}.

14. The method according to claim 13, wherein Based on defining two pilot subcarrier index groups for two predefined 106-tone RUs, The four pilot subcarrier indexes belong to at least one of the two pilot subcarrier index groups.

15. The method according to claim 1, wherein The one or more DRUs are indicated based on resource unit RU allocation information included in the PPDU, or The one or more DRUs are indicated based on RU allocation information included in a trigger frame for triggering transmission of the PPDU.

16. A first station (STA) device in a wireless local area network (WLAN) system, the device comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: generating a physical layer protocol data unit (PPDU) comprising one or more fields, the one or more fields being mapped on one or more distributed resource units (DRUs); and sending the PPDU to one or more second STAs over a bandwidth including a 20 MHz channel, wherein, based on the one or more DRUs comprising a 26-tone DRU, the 26-tone DRU is one of nine predefined 26-tone DRUs, wherein the nth 26-tone DRU includes the nth lowest subcarrier among the available subcarriers in the 20 MHz channel and is defined as every 9th subcarrier starting from the nth lowest subcarrier, n=1, 2, ..., 9, and The available subcarriers are subcarriers excluding 7 DC subcarriers, 4 null subcarriers, 11 protection subcarriers and 18 pilot subcarriers from the 256 subcarriers in the 20 MHz channel.

17. A method performed by a second station (STA) in a wireless local area network (WLAN) system, the method comprising the following steps: receiving a physical layer protocol data unit (PPDU) including one or more fields from a first STA over a bandwidth including a 20 MHz channel, decoding the one or more fields mapped on one or more distributed resource units DRU, wherein, based on the one or more DRUs comprising a 26-tone DRU, the 26-tone DRU is one of nine predefined 26-tone DRUs, wherein the nth 26-tone DRU includes the nth lowest subcarrier among the available subcarriers in the 20 MHz channel and is defined as every 9th subcarrier starting from the nth lowest subcarrier, n=1, 2, ..., 9, and The available subcarriers are subcarriers excluding 7 DC subcarriers, 4 null subcarriers, 11 protection subcarriers and 18 pilot subcarriers from the 256 subcarriers in the 20 MHz channel.

18. A second station (STA) device in a wireless local area network (WLAN) system, the device comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: receiving a physical layer protocol data unit (PPDU) including one or more fields from a first STA over a bandwidth including a 20 MHz channel, and decoding the one or more fields mapped on one or more distributed resource units DRU, wherein, based on the one or more DRUs comprising a 26-tone DRU, the 26-tone DRU is one of nine predefined 26-tone DRUs, wherein the nth 26-tone DRU includes the nth lowest subcarrier among the available subcarriers in the 20 MHz channel and is defined as every 9th subcarrier starting from the nth lowest subcarrier, n=1, 2, ..., 9, and The available subcarriers are subcarriers excluding 7 DC subcarriers, 4 null subcarriers, 11 protection subcarriers and 18 pilot subcarriers from the 256 subcarriers in the 20 MHz channel.

19. A processing device configured to control a station (STA) in a wireless local area network (WLAN) system, the processing device comprising: at least one processor; as well as At least one computer memory operatively connected to the at least one processor, the at least one computer memory storing instructions for performing the method according to any one of claims 1 to 15 upon execution by the at least one processor.

20. At least one non-transitory computer-readable medium storing at least one instruction, wherein: The at least one instruction is executed by at least one processor to control a device to execute the method according to any one of claims 1 to 15 in a wireless local area network (WLAN) system.

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