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

Abstract

Disclosed are a transmission and reception method and apparatus based on a restricted distributed resource unit tone plan in a wireless LAN system. A method performed by a first station (STA) in a wireless local area network (WLAN) system according to an embodiment of the present disclosure may comprise the steps of: generating a physical layer protocol data unit (PPDU) including one or more fields, where the one or more fields are mapped onto one or more distributed resource units (DRUs); and transmitting the PPDU to the one or more second STAs over a bandwidth including the 20 MHz channel. Regarding the PPDU related to the downlink transmission, based on the at least one or more DRUs including a 26-tone DRU, the 26-tone DRU may be one of eight predefined 26-tone DRUs related to a first short training field (STF) tone, excluding a specific 26-tone DRU, among nine predefined 26-tone DRUs.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for transmitting or receiving a tone plan based on a restricted distributed resource unit in a wireless local area network (WLAN) system. Background Art

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

[0003] To provide a more advanced wireless communication environment, improved technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for MIMO and multi-access point (AP) coordination that support increased bandwidth, efficient utilization of multiple frequency bands, and increased spatial streams are being studied. Specifically, various technologies are being studied to support low-latency or real-time services. Furthermore, new technologies are being discussed to support Ultra-High Reliability (UHR), including improvements or extensions to EHT technologies. Summary of the Invention

[0004] Technical issues

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

[0006] The technical objectives to be achieved by the present disclosure are not limited to the above-mentioned technical objectives, and those skilled in the art can clearly understand other technical objectives not described herein through the following description.

[0007] Technical Solution

[0008] According to one aspect of the present disclosure, a method performed by a first station (STA) in a wireless local area network (WLAN) system may include: generating a physical layer protocol data unit (PPDU) including at least one field, wherein the at least one field is mapped onto at least one distributed resource unit (DRU); and transmitting the PPDU to at least one second STA over a bandwidth including a 20 MHz channel. For a PPDU associated with downlink transmission, based on the at least one DRU including a 26-tone DRU, the 26-tone DRU may be one of eight predefined 26-tone DRUs associated with a first short training field (STF) tone, excluding a specific 26-tone DRU, among nine predefined 26-tone DRUs.

[0009] According to additional aspects of the present disclosure, a method performed by a second station (STA) in a wireless local area network (WLAN) system may include: receiving a physical layer protocol data unit (PPDU) including at least one field from a first STA over a bandwidth including a 20 MHz channel; and decoding the at least one field mapped to at least one distributed resource unit (DRU). For a PPDU associated with a downlink transmission, based on the at least one DRU including a 26-tone DRU, the 26-tone DRU may be one of eight predefined 26-tone DRUs associated with a first short training field (STF) tone, excluding a specific 26-tone DRU, among nine predefined 26-tone DRUs.

[0010] Technical Effects

[0011] According to the present disclosure, a method and apparatus for transmitting or receiving a tone plan based on a restricted distributed resource unit in a WLAN system may be provided.

[0012] Effects achievable by the present disclosure are not limited to the above-described effects, and other effects not described herein may be clearly understood by those skilled in the relevant art through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

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

[0019] Figure 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 7is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0021] 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.

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

[0023] Figure 12 is a diagram showing an exemplary format of a trigger frame to which the present disclosure may be applied.

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

[0025] Figure 14 is a diagram for explaining an example of a PPDU transmission method based on a restricted DRU tone schedule of a second STA according to the present disclosure. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure may be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art will appreciate that the present disclosure may be implemented without these specific details.

[0027] In some cases, well-known structures and devices may be omitted, or may be shown in the form of block diagrams based on the core functions of each structure and device in order to prevent ambiguity in the concepts of the present disclosure.

[0028] In the present disclosure, when an element is referred to as being "connected," "combined," or "linked" to another element, it may include an indirect connection relationship in which another element exists therebetween as well as a direct connection relationship. In addition, in the present disclosure, the terms "comprising" or "having" specify the presence of the mentioned features, steps, operations, components, and / or elements, but do not preclude the presence or addition of one or more other features, steps, operations, components, elements, and / or groups thereof.

[0029] In the present disclosure, terms such as "first," "second," etc. are used only to distinguish one element from another and are not used to limit the elements. Unless otherwise specified, they do not limit the order or importance of the elements. Therefore, within the scope of the present disclosure, the first element in one embodiment may be referred to as the second element in another embodiment, and similarly, the second element in one embodiment may be referred to as the first element in another embodiment.

[0030] The terms used in this disclosure are intended to describe specific embodiments and not to limit the claims. As used in the description of the embodiments and the appended claims, the singular is intended to include the plural, unless the context clearly indicates otherwise. The term "and / or" used in this disclosure may refer to one of the relevant enumerated items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise indicated, the " / " between words in this disclosure has the same meaning as "and / or".

[0031] 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.

[0032] Hereinafter, technical features of examples to which the present disclosure can be applied will be described.

[0033] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0034] Figure 1The 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.

[0035] Figure 1 The devices 100 and 200 illustrated in FIG. 1 may be referred to as stations (STAs). Figure 1 The devices 100 and 200 illustrated in the figure may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 may perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 may perform AP and / or non-AP functions. When the STAs 110 and 200 perform AP functions, they may be simply referred to as APs, and when the STAs 110 and 200 perform non-AP functions, they may be simply referred to as STAs. In addition, in the present disclosure, an AP may also be referred to as an AP STA.

[0036] Reference Figure 1 , the first device 100 and the second device 200 can transmit and receive radio signals through various wireless LAN technologies (e.g., IEEE 802.11 series). The first device 100 and the second device 200 can include interfaces for a media access control (MAC) layer and a physical layer (PHY) that conform to the IEEE 802.11 standard.

[0037] In addition to wireless LAN technology, the first device 100 and the second device 200 can also support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.). In addition, the device of the present disclosure can be implemented in various devices such as mobile phones, vehicles, personal computers, augmented reality (AR) devices, and virtual reality (VR) devices. In addition, the STA of this specification can support various communication services such as voice calls, video calls, data communications, autonomous driving, machine type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), IoT (Internet of Things), etc.

[0038] The first device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in this disclosure. For example, the processor 102 may generate first information / signals by processing information in the memory 104 and then transmit a wireless signal including the first information / signals via the transceiver 106. Alternatively, the processor 102 may receive a wireless signal including second information / signals via the transceiver 106 and then store information obtained through signal processing of the second information / signals in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for executing all or part of the processing controlled by the processor 102 or for executing the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in this disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used in conjunction with an RF (radio frequency) unit. In the present disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0039] The second device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in this disclosure. For example, the processor 202 may generate third information / signals by processing information in the memory 204, and then transmit a wireless signal including the third information / signals via the transceiver 206. Alternatively, the processor 202 may receive a wireless signal including fourth information / signals via the transceiver 206, and then store information obtained from signal processing of the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for executing all or part of the processing controlled by the processor 202 or for executing the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in this disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 206 may be connected to the processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used in conjunction with an RF unit. In the present disclosure, a device may refer to a communication modem / circuit / chip.

[0040] In the following, the hardware elements of the apparatus 100, 200 will be described in more detail. Without limitation, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors 102, 202 may generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors 102, 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors 102, 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, processes, suggestions, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106, 206. One or more processors 102, 202 may receive signals (e.g., baseband signals) from one or more transceivers 106, 206 and obtain PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, processes, suggestions, methods, and / or operational flow diagrams included in the present disclosure.

[0041] The one or more processors 102, 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in the one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in the present disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, functions, etc. The firmware or software configured to execute the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in the present disclosure may be included in the one or more processors 102, 202, or may be stored in one or more memories 104, 204 and driven by the one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods and / or operational flow diagrams included in the present disclosure may be implemented using firmware or software in the form of codes, instructions and / or instruction sets.

[0042] 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 drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 can be located internally and / or externally 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 via various technologies such as wired or wireless connections.

[0043] One or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc., as described in the methods and / or operational flowcharts, etc., of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc., as described, functions, processes, suggestions, methods, and / or operational flowcharts, etc., included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. In addition, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts, etc. included in the present disclosure through one or more antennas 108, 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert received wireless signals / channels, etc. from RF band signals into baseband signals to process the received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals into RF band signals. Thus, one or more transceivers 106 , 206 may include (analog) oscillators and / or filters.

[0044] For example, one of the STAs 100 and 200 may perform the intended operation of an AP, and the other of the STAs 100 and 200 may perform the intended operation of a non-AP STA. Figure 1 The transceivers 106 and 206 can perform signal transmission and reception operations (e.g., packets or physical layer protocol data units (PPDUs) compliant with IEEE 802.11a / b / g / n / ac / ax / be / bn). In addition, in the present disclosure, operations of various STAs generating transmission / reception signals or performing data processing or calculations on transmission / reception signals in advance can be performed by Figure 1The processors 102 and 202 of the STA may execute the operations of generating a transmit / receive signal or performing data processing or calculation for the transmit / receive signal in advance. For example, examples of operations of generating a transmit / receive signal or performing data processing or calculation for the transmit / receive signal in advance may include: 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signal (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / acquiring time resources or frequency resources (e.g., subcarrier resources) for fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / acquiring specific sequences (e.g., pilot sequences, STF / LTF sequences, additional sequences applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power saving operations applied to STAs; 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding of ACK signals, etc. In addition, in the following example, various information used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals (e.g., information related to fields / subfields / control fields / parameters / power, etc.) may be stored in Figure 1 in memories 104 and 204.

[0045] Hereinafter, the downlink (DL) may refer to a link used for communication from an AP STA to a non-AP STA, and DL PPDUs / packets / signals may be transmitted and received via the DL. In DL communication, the transmitter may be part of an AP STA, and the receiver may be part of a non-AP STA. The uplink (UL) may refer to a link used for communication from a non-AP STA to an AP STA, and UL PPDUs / packets / signals may be transmitted and received via the UL. In UL communication, the transmitter may be part of a non-AP STA, and the receiver may be part of an AP STA.

[0046] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0047] The structure of a wireless LAN system can be composed of multiple components. The interaction of multiple components can provide a wireless LAN that supports STA mobility that is transparent to upper layers. The basic service set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 It is exemplarily shown that two BSSs (BSS1 and BSS2) exist, and two STAs are included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2The ellipse representing the BSS in the figure can also be understood as representing the coverage area in which the STAs included in the corresponding BSS maintain communication. This area can be called the basic service area (BSA). When a STA moves outside the BSA, it cannot communicate directly with other STAs in the BSA.

[0048] If you don't consider Figure 2 , the most basic BSS type in a wireless LAN is an independent BSS (IBSS). For example, an IBSS may have a minimum form containing only two STAs. For example, assuming that other components are omitted, BSS1 containing only STA1 and STA2 or BSS2 containing only STA3 and STA4 may respectively correspond to representative examples of IBSSs. This configuration is possible when STAs can communicate directly 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 may 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 an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs may be composed of mobile STAs, and access to the distributed system (DS) is not allowed, thereby forming a self-contained network.

[0049] The membership of a STA in a BSS can be changed dynamically by turning the STA on or off, entering or exiting a BSS region, etc. To become a member of a BSS, a STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, a STA must associate with the BSS. This association can be established dynamically and can include the use of a distributed system service (DSS).

[0050] The direct STA-to-STA distance in a wireless LAN may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in some cases, communication between STAs at longer distances may be required. A distributed system (DS) can be configured to support extended coverage.

[0051] DS refers to the structure of BSS interconnection. Specifically, Figure 2As shown, the BSS can exist as an extended form of a network composed of multiple BSSs. DS is a logical concept and can be specified by the characteristics of the distributed system medium (DSM). At this point, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for a different purpose and is used by different components. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of the wireless LAN structure (DS structure or other network structure) can be interpreted as multiple 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 embodiment.

[0052] DS can support mobile devices by providing seamless integration of multiple BSSs and providing the logical services necessary to address the address leading to the destination. In addition, DS can also include a component called a portal, which is used as a bridge for connections between wireless LANs and other networks (e.g., IEEE 802.X).

[0053] The AP enables associated non-AP STAs to access the DS through the WM and means an entity that also has STA functionality. Data movement between the BSS and the DS can be performed through the AP. For example, Figure 2 STA2 and STA3 shown in the figure have STA functionality and provide functionality allowing associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs essentially correspond to STAs, all APs are addressable entities. The addresses used by APs for communication on the WM are not necessarily the same as the addresses used by APs for communication on the DSM. A BSS consisting of an AP and one or more STAs may be referred to as an infrastructure BSS.

[0054] Data sent from one of the STAs associated with the AP to the STA address of the corresponding AP can always be received at the uncontrolled port and can be processed by the IEEE 802.1X port access entity. In addition, when the controlled port is authenticated, the transmitted data (or frame) can be delivered to the DS.

[0055] In addition to the above-mentioned structure of the DS, an extended service set (ESS) can also be configured to provide wide coverage.

[0056] An ESS refers to a network of arbitrary size and complexity consisting of a DS and a BSS. An ESS may correspond to a set of BSSs connected to one DS. However, an ESS does not include a DS. An ESS network is characterized by being considered an IBSS in the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in an ESS may have the same service set identifier (SSID). The SSID is distinguished from the BSSID, which is an identifier of a BSS.

[0057] The wireless LAN system does not assume anything about the relative physical location of the BSSs, and all of the following forms are possible. BSSs can partially overlap, which is a form commonly used to provide continuous coverage. In addition, BSSs may not be physically connected, and logically, there is no limit on the distance between BSSs. In addition, BSSs can be physically located in the same location, which can be used to provide redundancy. In addition, one (or more than one) IBSS or ESS networks can physically exist in the same space as one (or more than one) ESS networks. When an ad hoc network operates in a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location, this can correspond to the form of an ESS network, etc.

[0058] Figure 3 is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0059] In order for a STA to establish a link with the network and send / receive data, it first discovers the network, performs authentication, establishes an association, and, for security reasons, performs authentication processing. The link establishment process may also be referred to as the session initiation process or the session establishment process. Furthermore, the discovery, authentication, association, and security establishment processes of the link establishment process may be collectively referred to as the association process.

[0060] In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation by the STA. In other words, in order for the STA to access the network, it needs to find a network it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying networks existing in a specific area is called scanning.

[0061] Scanning schemes include active scanning and passive scanning. Figure 3The network discovery operation including the active scanning process is exemplarily illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs exist around it while moving through the channel and waits for responses thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that has sent the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the channel being scanned. In the BSS, since the AP sends a beacon frame, the AP becomes the responder, and in the IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, a STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information included in the received probe response frame, and can move to the next channel (e.g., channel 2) and perform scanning in the same manner (i.e., sending and receiving probe requests / responses on channel 2).

[0062] Although not in Figure 3 Although not shown in FIG, a scanning operation can be performed in a passive scanning manner. In passive scanning, a scanning STA waits for a beacon frame while moving across channels. A beacon frame is one of the management frames defined in IEEE 802.11 and is periodically transmitted to notify the existence of a wireless network and allow a scanning STA to find and participate in the wireless network. In a BSS, an AP is used to periodically transmit beacon frames, and in an IBSS, STAs within the IBSS rotate to transmit beacon frames. When a scanning STA receives a beacon frame, the STA stores the BSS information included in the beacon frame and, while moving to another channel, records the beacon frame information in each channel. The STA that receives the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel in the same manner. Comparing active scanning with passive scanning, the advantage of active scanning is that it has less latency and consumes less power than passive scanning.

[0063] After the STA discovers the network, an authentication process may be performed at step S320. In order to clearly distinguish it from the security establishment operation of step S340 to be described later, this authentication process may be referred to as a first authentication process.

[0064] The authentication process includes the following process: the STA sends an authentication request frame to the AP, and in response thereto, the AP sends an authentication response frame to the STA. The authentication frame used for authentication request / response corresponds to a management frame.

[0065] The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), a limited cycle group, etc. This corresponds to some examples of information that can be included in the authentication request / response frame, and can be replaced with other information, or additional information can be included.

[0066] The STA can send an authentication request frame to the AP. The AP can determine whether to allow authentication of the corresponding STA based on the information included in the received authentication request frame. The AP can provide the result of the authentication process to the STA via an authentication response frame.

[0067] After the STA is successfully authenticated, an association process may be performed at step S330. The association process includes the following processes: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0068] For example, the association request frame may include information related to various capabilities, a beacon listening interval, a service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operation categories, a traffic indication map broadcast request (TIM broadcast request), interworking service capabilities, etc. For example, the association response frame may include information related to various capabilities, a status code, an association ID (AID), supported rates, an enhanced distributed channel access (EDCA) parameter set, a received channel power indicator (RCPI), a received signal-to-noise ratio indicator (RSNI), mobility domain, a timeout interval (e.g., association recovery time), overlapping BSS scan parameters, a TIM broadcast response, a quality of service (QoS) map, etc. This corresponds to some examples of information that may be included in the association request / response frame and may be replaced with other information or may further include additional information.

[0069] After the STA successfully associates with the network, a security establishment process may be performed at step S340. The security establishment process at step S340 may be referred to as an authentication process through a Robust Security Network Association (RSNA) request / response, the authentication process at step S320 may be referred to as a first authentication process, and the security establishment process at step S340 may also be referred to simply as an authentication process.

[0070] The security establishment process of step S340 may include, for example, a process of establishing a private key using a four-way handshake through an Extensible Authentication Protocol over LAN (EAPOL) frame. Alternatively, the security establishment process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0071] Figure 4 It is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0072] In wireless LAN systems, the basic access mechanism for medium access control (MAC) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC and essentially employs a "listen before talk" access mechanism. According to this type of access mechanism, before starting transmission, the AP and / or STA may perform Explicit Channel Assessment (CCA) to sense the radio channel or medium during a predetermined time interval (e.g., the DCF Interframe Space (DIFS)). As a result of this sensing, if the medium is determined to be idle, frame transmission is initiated via the corresponding medium. On the other hand, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not initiate its own transmission and may set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after the wait. By applying a random backoff period, collisions can be minimized because multiple STAs are expected to attempt frame transmission after waiting for different time periods.

[0073] In addition, the IEEE 802.11 MAC protocol provides a hybrid coordination function (HCF). HCF is based on DCF and point coordination function (PCF). PCF is a synchronous access method based on polling, and refers to a method in which all receiving APs and / or STAs periodically poll to receive data frames. In addition, HCF has enhanced distributed channel access (EDCA) and HCF controlled channel access (HCCA). EDCA is a contention-based access method that provides data frames to multiple users in a direction, and HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, HCF includes a medium access mechanism for improving the QoS (quality of service) of a wireless LAN, and QoS data can be sent in a contention period (CP) and a contention-free period (CFP).

[0074] Reference Figure 4, the operation based on the random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs may attempt to send data (or frames). As a method of minimizing collisions, each of the STAs may select a random backoff count respectively and attempt to send after waiting for the corresponding time slot time. The random backoff count has a pseudo-random integer value and may be determined as one of the values ​​ranging from 0 to CW. Here, CW is the contention window parameter value. The CW parameter is assigned CWmin as an initial value, but may take a value twice as large in the event of a transmission failure (for example, when an ACK for the transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission may be attempted while maintaining the CWmax value until the data transmission is successful, and when the data transmission is successful, the CWmin value is reset. The values ​​of CW, CWmin, and CWmax are preferably set to 2n-1 (n=0, 1, 2, ...).

[0075] When the random backoff process starts, the STA continuously monitors the medium during the backoff slot countdown according to the determined backoff count value. When the medium is monitored for occupancy, it stops the countdown and waits, and restarts the remaining countdown when the medium becomes idle.

[0076] exist Figure 4 In the example shown, when a packet to be transmitted arrives at STA3's MAC, STA3 can immediately transmit a frame after confirming that the medium has been idle for DIFS. The remaining STAs monitor and wait for the medium to become occupied / busy. Meanwhile, data to be transmitted can also occur at each of STA1, STA2, and STA5. When the medium is detected as idle, each STA waits for DIFS and then begins counting down the backoff slot based on a random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. This example illustrates a situation where, when STA2 completes the backoff count and begins frame transmission, STA5's remaining backoff time is shorter than STA1's. STA1 and STA5 temporarily stop the countdown and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and restart the backoff count where they left off. This means that frame transmission can begin after counting down the remaining backoff slots for the remaining backoff time. Since STA5's remaining backoff time is shorter than STA1's, STA5 begins frame transmission. While STA2 is occupying the medium, data transmission can also occur in STA4. From STA4's perspective, when the medium becomes idle, STA4 can wait for DIFS, then perform a countdown based on a random backoff count value selected by STA4 and begin frame transmission. 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.

[0077] 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.

[0078] 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.

[0079] Figure 5 is a diagram for explaining a frame transmission operation based on CSMA / CA to which the present disclosure can be applied.

[0080] As described above, in addition to physical carrier sensing in which STAs directly sense the medium, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing is intended to compensate for problems such as hidden node problems that may occur in medium access. For virtual carrier sensing, the STA's MAC can use a network allocation vector (NAV). NAV is a value that indicates to other STAs the remaining time until the medium is available for use by STAs that are currently using or have the right to use the medium. Therefore, the value set to NAV corresponds to the period during which the STA sending the frame plans to use the medium, and during the corresponding period, the STA receiving the NAV value is prohibited from accessing the medium. For example, NAV can be configured based on the value of the "Duration" field of the MAC header of the frame.

[0081] exist Figure 5 In the example of FIG, it is assumed that STA1 intends to send data to STA2, and STA3 is in a position to be able to eavesdrop on some or all frames sent and received between STA1 and STA2.

[0082] In order to reduce the possibility of transmission collisions between multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example of , when STA1 is transmitting, as a result of STA3's carrier sensing, it can be determined that the medium is in an idle state. That is, STA1 may correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 In the example shown in FIG1 , it can be determined that the medium is idle based on STA3's carrier sensing result while STA2 is transmitting. In other words, STA2 may correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or outside the carrier sensing range of STA1 or STA3's transmission, can avoid attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0083] Specifically, STA1 can determine whether a channel is in use 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 use the network allocation vector (NAV) timer to determine the channel occupancy state.

[0084] When the channel is idle for DIFS, STA1 may send an RTS frame to STA2 after backoff. When STA2 receives the RTS frame, STA2 may send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0085] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the subsequent frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 can overhear a CTS frame from STA2, even if STA3 cannot overhear an RTS frame from STA1, STA3 can use the duration information included in the CTS frame to set the NAV timer for the subsequent frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame). In other words, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0086] When STA1 receives a CTS frame from STA2, STA1 can send a data frame to STA2 after SIFS, starting from the time the CTS frame is received. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 can determine whether the channel is in use through carrier sensing. If STA3 determines that the channel is not in use by other terminals during the DIFS period after the NAV timer expires, STA3 can attempt channel access after the contention window (CW) based on random backoff has expired.

[0087] Figure 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.

[0088] The PHY layer can prepare the MAC PDU (MPDU) to be transmitted with the help of instructions or primitives (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 transmit mode, configures the information provided by the MAC layer (e.g., data) 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 the header of the preamble and sends a command to the MAC layer to notify the PHY layer of the start of reception.

[0089] In this manner, information transmission / reception in the wireless LAN system is performed in the form of frames, and for this purpose, a PHY layer protocol data unit (PPDU) format is defined.

[0090] The basic PPDU may include a short training field (STF), a long training field (LTF), a signal (SIG) field, and a data (Data) field. Figure 7 The non-HT (high throughput) field shown in FIG may consist only of the legacy-STF (L-STF), legacy-LTF (L-LTF), legacy-SIG (L-SIG) field, and the 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) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the data field.

[0091] STF is a signal used for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., and LTF is a signal used for channel estimation and frequency error estimation. STF and LTF can be called signals for synchronization and channel estimation of the OFDM physical layer.

[0092] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits and may include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity field, and a 6-bit tail field. The RATE field may include information about the modulation and coding rate of the data. For example, the 12-bit length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit length field may be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field may be determined as a multiple of 3. For example, for HE PPDUs, the value of the length field may be determined as a multiple of 3+1 or 3+2.

[0093] The data field may include a service (SERVICE) field, a physical layer service data unit (PSDU), and PPDU tail bits, and may also include padding bits if necessary. Some bits of the service field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in upper layers. The PPDU tail bits may be used to return the encoder to the 0 state. The padding bits may be used to adjust the length of the data field in predetermined units.

[0094] 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). A MAC frame can be composed of MAC PDUs and transmitted / received through PSDU of the data portion of the PPDU format.

[0095] The MAC header includes a frame control field, a duration / ID field, an address field, and other fields. The frame control field may include control information required for frame transmission / reception. The duration / ID field may be set to the time for transmitting the corresponding frame, etc. For details on the sequence control, QoS control, and HT control subfields of the MAC header, refer to the IEEE 802.11 standard.

[0096] The Null Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, the NDP refers to a frame format that includes the PPDU preamble of the general PPDU format (i.e., the L-STF, L-LTF, L-SIG fields, and additional non-legacy SIG, non-legacy STF, and non-legacy LTF (if present)) and does not include the remaining portion (i.e., the data field).

[0097] Figure 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0098] In standards such as IEEE 802.11a / g / n / ac / ax, various types of PPDUs have been used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and data fields. The basic PPDU format may also be referred to as a non-HT PPDU format (e.g., Figure 7 (as shown in (a)).

[0099] Compared to the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields. Figure 7The HT PPDU format shown in (b) may be referred to as an HT mixed format. Furthermore, an HT greenfield format PPDU may be defined, and this corresponds to a format 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 (not shown).

[0100] Compared to the basic PPDU format, an example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHTSIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (e.g., Figure 7 (as shown in (c)).

[0101] Compared to the basic PPDU format, an example of the HE PPDU format (IEEE 802.11ax) additionally includes a repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, a packet extension (PE) field (such as Figure 7 (d) of FIG). Some fields may be excluded or their lengths may vary according to the detailed example of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single user (SU). In addition, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary up to 8 μs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary up to 16 μs. For example, the RL-SIG may be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA may know whether the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0102] The EHT PPDU format may include Figure 7 (e) EHT MU (Multi-User) and Figure 7 The EHT TB (trigger-based) PPDU in (f) of FIG. The EHT PPDU format is similar to the HE PPDU format in that it includes the RL-SIG following the L-SIG, but may include the U (Universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0103] Figure 7The EHT MU PPDU in (e) corresponds to a PPDU that carries 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.

[0104] Compared with EHT MU PPDU, Figure 7 The EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for UL MU transmission (eg, a trigger frame or a triggered response schedule (TRS)) may perform UL transmission based on the EHT TB PPDU format.

[0105] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), and EHT-SIG fields may be coded and modulated so that even legacy STAs can attempt demodulation and decoding, and may be mapped based on a determined subcarrier frequency spacing (e.g., 312.5 kHz). These may be referred to as pre-EHT modulation fields. Subsequently, the EHT-STF, EHT-LTF, data, and PE fields may be coded and modulated so that STAs that successfully decode non-legacy SIGs (e.g., U-SIG and / or EHT-SIG) and obtain the information included in these fields may be demodulated and decoded, and may be mapped based on a determined subcarrier frequency spacing (e.g., 78.125 kHz). These may be referred to as EHT modulation fields.

[0106] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields may be referred to as HE modulation fields. Furthermore, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields may be referred to as VHT modulation fields.

[0107] Included in Figure 7The U-SIG in the EHT PPDU format may be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol used for the U-SIG (e.g., OFDM symbol) may have a duration of 4 μs, and the U-SIG may have a total duration of 8 μs. Each symbol of the U-SIG may be used to transmit 26 bits of information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0108] The U-SIG can be constructed in 20MHz units. For example, if an 80MHz PPDU is constructed, the U-SIG can be duplicated. That is, the same four U-SIGs can be included in the 80MHz PPDU. PPDUs with bandwidth exceeding 80MHz can include different U-SIGs.

[0109] For example, A uncoded bits may be transmitted via the U-SIG, the first symbol of the U-SIG (e.g., the U-SIG-1 symbol) may transmit the first X bits of information out of a total of A bits of information, and the second symbol of the U-SIG (e.g., the U-SIG-2 symbol) may transmit the remaining Y bits of information out of a total of A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit field). For example, the tail field may be used to terminate the trellis structure of the convolutional decoder and may be set to 0.

[0110] The bit information sent through U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in Figure 7 The U-SIG field format may be included in a new PPDU format (e.g., UHR PPDU format) not shown in the EHT PPDU format and may be included in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format. The version-independent bits may be the same, and some or all of the version-dependent bits may be different.

[0111] For example, the size of the version-independent bits of the U-SIG can be fixed or variable. The version-independent bits can be assigned only to the U-SIG-1 symbol, or 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 the first control bit and the second control bit.

[0112] For example, the version-independent bits of the U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version of the transmitted / received PPDU (e.g., EHT, UHR, etc.). The version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field is related to UL communication, and the second value of the UL / DL flag field is related to DL communication. The version-independent bits of the U-SIG may include information about the length of a transmit opportunity (TXOP) and information about a BSS color ID.

[0113] For example, the version-related bits of the U-SIG may include information directly or indirectly indicating the type of the PPDU (eg, SUPPDU, MU PPDU, TB PPDU, etc.).

[0114] Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may also include information about bandwidth, information about the MCS technology applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether the DCM (Dual Carrier Modulation) technology (e.g., a technology for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and information about whether the non-legacy SIG is generated across the entire frequency band.

[0115] Some of the information required for PPDU transmission and reception may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information on the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information on the length of the non-legacy LTF and the CP (Cyclic Prefix) length, information on the GI (Guard Interval) applicable to the non-legacy LTF, information on preamble puncturing applicable to the PPDU, information on resource unit (RU) allocation, etc. may be included only in the U-SIG, only in the non-legacy SIG, or may be indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0116] Preamble puncturing may indicate transmission of a PPDU in which no signal exists in one or more frequency bins within the PPDU's bandwidth. For example, the size of a frequency bin (or the resolution of preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or greater.

[0117] exist Figure 7In the example of [ ], non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for receiving STAs. A non-legacy SIG may be transmitted over at least one symbol, and one symbol may be 4 μs long. Information regarding the number of symbols used for the EHT-SIG may be included in a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0118] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include common fields and user-specific fields. The common fields and user-specific fields may be encoded separately.

[0119] In some cases, the common field can be omitted. For example, in compressed mode without OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive the PPDU (e.g., the data field of the PPDU) on the same frequency band. In non-compressed mode with OFDMA, multiple users can receive the PPDU (e.g., the data field of the PPDU) on different frequency bands.

[0120] The number of user-specific fields may be determined based on the number of users. A user block field may include up to two user fields. Each user field may be associated with a MU-MIMO allocation or may be associated with a non-MU-MIMO allocation.

[0121] The common field may include CRC bits and tail bits, and the length of the CRC bits may be determined to be 4 bits, while the length of the tail bits may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the positions of the RUs to which multiple users (i.e., multiple receiving STAs) are assigned.

[0122] A RU can include multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA technology. In addition, RUs can be defined even when transmitting signals to a single STA. Resources can be allocated for non-legacy STFs, non-legacy LTFs, and data fields in units of RUs.

[0123] The applicable RU size can be defined based on the PPDU bandwidth. The RU can be defined identically or differently for the applied PPDU format (e.g., HEPPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU layout of the HEPPDU and EHT PPDU can be different. The applicable RU size, the number of RUs and RU positions, the DC (direct current) subcarrier position and number, the null subcarrier position and number, the guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, a tone plan for high bandwidth can be defined in the form of multiple iterations of a low bandwidth tone plan.

[0124] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, and the like. An MRU (Multi-RU) is different from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs. For example, an MRU can be defined as 52+26-tones, 106+26-tones, 484+242-tones, 996+484-tones, 996+484+242-tones, 2×996+484-tones, 3×996-tones, or 3×996+484-tones. In addition, the multiple RUs that make up an MRU may or may not be contiguous in the frequency domain.

[0125] The specific size of an RU can be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not restrictive but illustrative. In addition, in this disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, etc.), the number of RUs can vary depending on the RU size.

[0126] Figure 7 The names of each field in the PPDU format are exemplary, and the scope of the present disclosure is not limited by these names. In addition, the examples of the present disclosure can be applied to Figure 7 The PPDU format shown in Figure 7 A new PPDU format that excludes some fields and / or adds some fields to the existing PPDU format.

[0127] Resource Unit

[0128] 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.

[0129] Reference Figures 8 to 10In this article, we will describe the resource unit (RU) defined in the wireless LAN system. A RU can include multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on the OFDMA scheme. In addition, RUs can be defined even when a signal is transmitted to a single STA. RUs can be used for the data field, STF, LTF, etc. of a PPDU.

[0130] like Figures 8 to 10 As shown in , RUs corresponding to different numbers of tones (i.e., subcarriers) are used to construct some fields of a 20 MHz, 40 MHz, or 80 MHz X-PPDU (X is HE, EHT, etc.). For example, resources can be allocated in RU units as shown for the X-STF, X-LTF, and data fields.

[0131] Figure 8 is a diagram illustrating an exemplary allocation of resource units (RUs) used on a 20 MHz frequency band.

[0132] like Figure 8 As shown at the top of the figure, 26 units (i.e., units corresponding to 26 tones) can be allocated. Six tones can be used as a guard band in the leftmost band of the 20 MHz band, and five tones can be used as a guard band in the rightmost band of the 20 MHz band. In addition, seven DC tones are inserted into the center band (i.e., the DC band), and 26 units corresponding to each of the 13 tones can exist on the left and right sides of the DC band. Furthermore, 26 units, 52 units, and 106 units can be allocated to other bands. Each unit can be allocated for either an STA or a user.

[0133] Figure 8 The RU allocation is used not only for the multi-user (MU) case but also for the single-user (SU) case, and in this case, a 242-unit can be used, such as Figure 8 In this case, three DC tones can be inserted.

[0134] exist Figure 8 In the examples, various sizes of RUs are illustrated, that is, 26-RU, 52-RU, 106-RU, 242-RU, etc., but the specific sizes of these RUs can be reduced or expanded. Therefore, in the present disclosure, the specific size of each RU (i.e., the number of corresponding tones) is exemplary and not restrictive. In addition, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, ...) in the present disclosure, the number of RUs can vary depending on the size of the RU. In the following description, Figure 9 and / or Figure 10In the example, the fact that the size and / or number of RUs can vary is related to Figure 8 Same as the example.

[0135] Figure 9 is a diagram illustrating an exemplary allocation of resource units (RUs) used on a 40 MHz frequency band.

[0136] As in Figure 8 As in the example using various RU sizes, you can also Figure 9 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.

[0137] Additionally, as shown, when used for a single user, 484-RU may be used.

[0138] Figure 10 is a diagram illustrating an exemplary allocation of resource units (RUs) used on an 80 MHz frequency band.

[0139] As in Figure 8 and 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, 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 is present on the left and right sides of the DC band, the EHT PPDU has 23 DC tones inserted in the DC band and one 26-RU on the left and right sides of the DC band. Unlike the HE PPDU, in which one null subcarrier is present 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.

[0140] Additionally, as shown, when used for a single user, 996-RU may be used, and in this case, 5 DC tones are inserted as with HEPPDU and EHT PPDU.

[0141] exist Figure 10 In the 160MHz EHT PPDU, multiple 80MHz sub-blocks can be configured. The RU allocation for each 80MHz sub-block can be the same as Figure 10 If the 80 MHz sub-block of a 160 MHz or 320 MHz EHT PPDU is not punctured and the entire 80 MHz sub-block is used as a RU or part of a multiple RU (MRU), the 80 MHz sub-block can be used. Figure 10 996-RU.

[0142] Here, an MRU corresponds to a group of subcarriers (or tones) consisting of multiple RUs, and the multiple RUs constituting the MRU may be RUs of the same size or RUs of different sizes. For example, a single MRU may be defined as 52+26-tones, 106+26-tones, 484+242-tones, 996+484-tones, 996+484+242-tones, 2×996+484-tones, 3×996-tones, or 3×996+484-tones. Here, the multiple RUs constituting one MRU may correspond to a small size (e.g., 26, 52, or 106) RU or a large size (e.g., 242, 484, or 996) RU. That is, one MRU including small size RUs and large size RUs may not be configured / defined. In addition, the multiple RUs constituting one MRU may be continuous or non-contiguous in the frequency domain.

[0143] When an 80 MHz sub-block includes an RU that is less than 996 tones or a portion of the 80 MHz sub-block is punctured, the 80 MHz sub-block may use RU allocations other than the 996-tone RU.

[0144] 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.

[0145] 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.

[0146] Distributed resource unit

[0147] 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.

[0148] 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.

[0149] When the PSD limitation is overcome, the transmit power can be increased, thereby improving spectral efficiency or extending range.

[0150] Given 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-contiguous, so each tone can be transmitted at high power. RUs that include tones distributed in this manner are called distributed RUs (DRUs), and to distinguish them from RUs that include contiguous tones defined in existing WLAN systems (e.g., systems according to IEEE 802.11ax, 11be, etc.) are referred to as regular RUs (RRUs).

[0151] Compared to STAs transmitting conventional RRUs, STAs transmitting DRUs can use higher power. For example, a 52-tone DRU across 80 MHz has only one tone per MHz, while a 52-tone RRU has approximately 13 tones per MHz. Assuming a PSD limit of -1 dBm / MHz in the 6 GHz LPI band, for a 52-tone RU, the transmit power can be increased by approximately 11 dB when using a DRU. Increasing transmit power in this way allows for higher MCSs and supports longer ranges.

[0152] Figure 11 is a diagram for explaining an example of a DRU to which the present disclosure can be applied.

[0153] Figure 11 The example illustratively shows STA1 transmitting on DRU1, STA2 transmitting on DRU2, and STA3 transmitting on DRU3. Each STA can apply a transmit power boost by using a DRU. Compared to using an RRU of the same size, higher transmit power is applied to all tones in the DRU, significantly improving spectral efficiency. In this way, DRUs can be usefully applied, particularly in UL OFDMA.

[0154] In the case of an AP, DRUs may also be utilized. In some cases, the AP may perform DL-OFDMA transmissions to STAs by using only some of DRU1, DRU2, and DRU3, and in this case, the transmission power boost due to the use of DRUs may be applied.

[0155] In order to maximize the power boost, the tones within a DRU can be distributed as far 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 available tones included in a DRU (i.e., the number of remaining tones excluding unavailable tones such as null tones, guard tones, DC tones)) can be defined to be the same as the size of the RRU (or the number of available tones included in an RRU). Therefore, the impact on various technologies previously defined based on RRUs can be minimized. The following table shows examples of achievable power boosts (in dB) for various DRUs distributed over different bandwidths. The examples in the table below assume the 6 GHz LPI band, and power boosts can also be obtained in other areas in the 2.4 GHz band and the 5 GHz band. For example, in an 80 MHz UL-OFDMA transmission performed by 8 users, when each user uses a 106-tone DRU, the overall performance can be improved by approximately 8.13 dB compared to when each user uses a 106-tone RRU. In this way, the DRU can be used to overcome PSD limitations and achieve significant benefits.

[0156] [Table 1]

[0157] 20MHz bandwidth 40MHz bandwidth 80MHz bandwidth 26-tone RU 8.13 11.14 11.14 52-tone RU 6.37 8.13 11.14 106-Tone RU 3.36 6.37 8.13 242-Tone RU not applicable 2.69 5.12 484-Tone RU not applicable not applicable 2.69

[0158] Trigger Frame

[0159] Figure 12 is a diagram showing an example format of a trigger frame to which the present disclosure may be applied.

[0160] The trigger frame can allocate resources for at least one TB PPDU and request TB PPDU transmission. The trigger frame can also include other information required by the STA to transmit the TB PPDU in response. The trigger frame can include common information and user information list fields in the frame body.

[0161] The common information field may include information that is commonly applied to at least one TB PPDU sent by a trigger frame request, such as trigger type, UL length, whether there are subsequent trigger frames (e.g., more TFs), whether channel sensing (CS) is required, UL bandwidth (BW), etc. Figure 12 The EHT variant common information field format is exemplarily shown.

[0162] The 4-bit Trigger Type subfield can have values ​​0 to 15. Among them, the 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 Acknowledgement Request), MU-RTS (Multi-User-Request to Send), BSRP (Buffer Status Report Poll), GCR (Multicast with Retry) MU-BAR, BQRP (Bandwidth Query Report Poll), and NFRP (NDP Feedback Report Poll), and the values ​​8 to 15 are defined as reserved.

[0163] Among the common information, the trigger-related common information subfield may include information selectively included based on the trigger type.

[0164] A special user information field may be included in the trigger frame. The special user information field does not include user-specific information, but includes extended common information that is not provided in the common information field.

[0165] The user information list includes at least 0 user information fields. Figure 12 The EHT variant user information field format is exemplarily shown.

[0166] The AID12 subfield essentially indicates that it is a user information field for the STA with the corresponding AID. Additionally, 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 it as a special user information field. A special user information field is a user information field that does not include user-specific information but includes extended public information not provided in the public information field. For example, the special user information field can be identified by the AID12 value 2007, and the special user information field flag subfield in the public information field can indicate whether the special user information field is included.

[0167] The RU allocation subfield may indicate the size and location of the RU / MRU. For this purpose, the RU allocation subfield may be interpreted together with the PS160 (primary / secondary 160 MHz) subfield of the user information field, the UL BW subfield of the common information field, etc.

[0168] For example, as shown in Table 2 below, the mapping of B7-B1 of the RU Allocation subfield can be defined together with the settings of B0 and PS160 subfields of the RU Allocation subfield. Table 2 shows an example of encoding of the PS160 subfield and the RU Allocation subfield of the EHT Variant User Information field.

[0169] [Table 2]

[0170]

[0171]

[0172] When B0 of the RU Allocation subfield is set to 0, it may indicate that RU / MRU allocation is applied to the primary 80 MHz channel, and when the value is set to 1, it may 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 may indicate that RU / MRU allocation is applied to the lower 80 MHz of the secondary 160 MHz, and when the value is set to 1, it may indicate that RU allocation is applied to the upper 80 MHz of the secondary 160 MHz.

[0173] In the trigger frame RU allocation table of Table 2, the parameter N can be calculated based on the formula N=2*X1+X0. For bandwidths 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 represents the absolute frequency order for the primary and secondary 80 MHz and 160 MHz channels. The order from left to right represents the order from 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.

[0174] [Table 3]

[0175]

[0176] Send and receive based on DRU tone plan

[0177] As described above, to overcome the PSD limitation and improve the power gain, a DRU using distributed tones / subcarriers may be applied instead of an RRU using continuous tones / subcarriers.

[0178] In the present disclosure, for DRU-based transmission / reception of PPDUs in a bandwidth including a 20 MHz channel, definitions of DRU tone plans of various sizes and a transmission / reception method based thereon are described.

[0179] The tone plan for 20 MHz bandwidth may include support for existing RRUs of various sizes according to the present disclosure (e.g., Figure 8) and examples of DRUs of various sizes. In a tone plan applied to 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 can be defined that supports 26-tone DRUs, 52-tone DRUs, and 106-tone DRUs for a 20 MHz bandwidth, but a 242-tone DRU may not support the tone / subcarrier distribution and is therefore not included in the examples of this disclosure.

[0180] In the examples of the present disclosure, it is assumed that the number and position of DC subcarriers, null subcarriers, and guard subcarriers in the DRU tone plan for 20 MHz bandwidth are the same as the number and position of DC subcarriers, null subcarriers, and guard subcarriers in the RRU tone plan for 20 MHz bandwidth. In other words, among the 256 subcarriers within the 20 MHz bandwidth, the DC subcarrier may correspond to the middle 7 subcarriers of the 20 MHz bandwidth, and the guard subcarriers may correspond to the leftmost 6 subcarriers and the rightmost 5 subcarriers of the 20 MHz bandwidth. The null subcarriers may correspond to four (subcarrier indices -122, -69, 69, 122) for 26-tone DRU and 52-tone DRU, and the null subcarriers shall not be used for 106-tone DRU (i.e., the four null subcarrier positions considered in the 26-tone DRU and 52-tone DRU are used as available subcarriers in the 106-tone DRU). In the following description, the remaining subcarriers excluding the DC subcarrier, the null subcarrier, and the guard subcarrier within the bandwidth may be referred to as available subcarriers.

[0181] In the embodiments described below, the DRU index (i.e., DRU-n) or the nth DRU may correspond to a position in the frequency domain, or may be assigned without regard to the position in the frequency domain. In the embodiments described below, for 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 may be assigned in various ways to distinguish different DRUs.

[0182] Furthermore, in the following description, the subcarrier index assumes that the DC subcarrier has an index of 0 and corresponds to a position in the frequency domain, and the term subcarrier may be replaced with tone.

[0183] In addition, in the following description, the expression a:b:c for subcarrier index refers to from subcarrier index a to subcarrier index c to every b subcarrier index. In addition, in the following description, +-{a:b:c} refers to {-a:b:-c,a:b:c}.

[0184] Implementation Method 1

[0185] In this embodiment, various examples of configuring subcarrier indices for a 26-tone DRU are described.

[0186] Implementation Method 1-1

[0187] This embodiment relates to a method for allocating one subcarrier to each of the nine 26-tone DRUs in order from the lowest available subcarrier to the highest available subcarrier.For example, each of the nine 26-tone DRUs may include the following subcarriers.

[0188] 26-tone DRU-1: -121:9:-76, -66:9:-12, 4:9:67, 77:9:113

[0189] 26-tone DRU-2: -120:9:-75, -65:9:-11, 5:9:68, 78:9:114

[0190] 26-tone DRU-3: -119:9:-74, -64:9:-10, 6:9:60, 70:9:115

[0191] 26-tone DRU-4: -118:9:-73, -63:9:-9, 7:9:61, 71:9:116

[0192] 26-tone DRU-5: -117:9:-72, -62:9:-8, 8:9:62, 72:9:117

[0193] 26-tone DRU-6: -116:9:-71, -61:9:-7, 9:9:63, 73:9:118

[0194] 26-tone DRU-7: -115:9:-70, -60:9:-6, 10:9:64, 74:9:119

[0195] 26-tone DRU-8: -114:9:-78, -68:9:-5, 11:9:65, 75:9:120

[0196] 26-tone DRU-9: -113:9:-77, -67:9:-4, 12:9:66, 76:9:121

[0197] Implementation 1-2

[0198] This embodiment relates to a method for allocating one subcarrier to each of the nine 26-tone DRUs in order from the lowest available subcarrier to the highest available subcarrier below the DC subcarrier (i.e., a negatively indexed subcarrier), and allocating corresponding subcarriers (i.e., positively indexed subcarriers) that are mirror-symmetric between the allocated subcarrier and the DC subcarrier to the 26-tone DRUs including the allocated subcarriers. For example, each of the nine 26-tone DRUs may include the following subcarriers.

[0199] 26-tone DRU-1: +-{12:9:66,76:9:121}

[0200] 26-tone DRU-2: +-{11:9:65,75:9:120}

[0201] 26-tone DRU-3: +-{10:9:64,74:9:119}

[0202] 26-tone DRU-4: +-{9:9:63,73:9:118}

[0203] 26-tone DRU-5: +-{8:9:62,72:9:117}

[0204] 26-tone DRU-6: +-{7:9:61,71:9:116}

[0205] 26-tone DRU-7: +-{6:9:60,70:9:115}

[0206] 26-tone DRU-8: +-{5:9:68,78:9:114}

[0207] 26-tone DRU-9: +-{4:9:67,77:9:113}

[0208] Implementation 1-3

[0209] This embodiment involves a method for transmitting the signal in a sequence from the lowest available subcarrier to the highest available subcarrier (excluding the subcarrier corresponding to the middle 26-tone RRU (refer to Figure 8 A method for allocating one subcarrier to each of eight 26-tone DRUs (referred to as a 26-tone RRU-5) is described. The 26-tone DRU-5 can use an existing 26-tone RRU-5 as is (in this case, the 26-tone DRU-5 can function as an RRU rather than a DRU, as it does not actually include distributed subcarriers). In this way, a total of nine 26-tone DRUs can be defined. For example, each of the nine 26-tone DRUs can include the following subcarriers.

[0210] 26-tone DRU-1: -121:8:-73, -64:8:-24, 17:8:65, 74:8:114

[0211] 26-tone DRU-2: -120:8:-72, -63:8:-23, 18:8:66, 75:8:115

[0212] 26-tone DRU-3: -119:8:-71, -62:8:-22, 19:8:67, 76:8:116

[0213] 26-tone DRU-4: -118:8:-70, -61:8:-21, 20:8:68, 77:8:117

[0214] 26-tone DRU-5: +-{4:1:16} (same as 26-tone RRU-5)

[0215] 26-tone DRU-6: -117:8:-77, -68:8:-20, 21:8:61, 70:8:118

[0216] 26-tone DRU-7: -116:8:-76, -67:8:-19, 22:8:62, 71:8:119

[0217] 26-tone DRU-8: -115:8:-75, -66:8:-18, 23:8:63, 72:8:120

[0218] 26-tone DRU-9: -114:8:-74, -65:8:-17, 24:8:64, 73:8:121

[0219] Implementation Methods 1-4

[0220] This embodiment involves a method for performing a multi-level ... Figure 8A method is used to allocate one subcarrier to each of the nine 26-tone DRUs (referred to as a 26-tone RRU-5) in the order of subcarriers, and to allocate corresponding subcarriers (i.e., positively indexed subcarriers) based on the mirror symmetry between the allocated subcarriers and the DC subcarrier to the 26-tone DRUs including the allocated subcarriers. The 26-tone DRU-5 can use the existing 26-tone RRU-5 as is (in this case, the 26-tone DRU-5 can be used as an RRU rather than a DRU because it does not actually include distributed subcarriers). In this way, a total of nine 26-tone DRUs can be defined. For example, each of the nine 26-tone DRUs can include the following subcarriers.

[0221] 26-tone DRU-1: +-{24:8:64,73:8:121}

[0222] 26-tone DRU-2: +-{23:8:63,72:8:120}

[0223] 26-tone DRU-3: +-{22:8:62,71:8:119}

[0224] 26-tone DRU-4: +-{21:8:61,70:8:118}

[0225] 26-tone DRU-5: +-{4:1:16} (same as 26-tone RRU-5)

[0226] 26-tone DRU-6: +-{20:8:68,77:8:117}

[0227] 26-tone DRU-7: +-{19:8:67,76:8:116}

[0228] 26-tone DRU-8: +-{18:8:66,75:8:115}

[0229] 26-tone DRU-9: +-{17:8:65,74:8:114}

[0230] In the above examples, Embodiments 1-1 and 1-2 include subcarriers that are more evenly distributed within each DRU than Embodiments 1-3 and 1-4, and therefore may be advantageous in terms of power gain. Furthermore, Embodiments 1-1 and 1-3 may be advantageous in terms of channel estimation performance because, compared to Embodiments 1-2 and 1-4, the spacing between subcarriers within each DRU is consistently maintained, making it easier to apply interpolation techniques, etc. Furthermore, Embodiments 1-2 and 1-4 may be expected to achieve better performance depending on the application because, compared to Embodiments 1-1 and 1-3, the subcarrier spacing is symmetrical around DC.

[0231] In addition to including subcarrier indices in the 26-tone DRU as in the examples of Embodiments 1-1 to 1-4 above, subcarrier indices may be assigned to the 26-tone DRU in various ways. For example, while the above examples assume that available subcarriers do not include guard subcarriers, null subcarriers, and DC subcarriers, it is also possible to assume that available subcarriers include at least one of guard subcarriers, null subcarriers, or DC subcarriers, and define subcarrier indices to be included in each 26-tone DRU.

[0232] Implementation Method 2

[0233] In this embodiment, various examples of configuring subcarrier indices for a 52-tone DRU are described.

[0234] For example, four 52-tone DRUs can be defined within a 20 MHz 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 above. If 26-tone DRU-5 is not used as the basis for a 52-tone DRU, a combination of two of the eight 26-tone DRUs can correspond to one 52-tone DRU.

[0235] The two 26-tone DRUs corresponding to one 52-tone DRU may correspond to those DRUs that are spaced as far apart as possible in the frequency domain and distribute the subcarriers evenly to the 52-tone DRUs.The four 52-tone DRUs may be defined as follows.

[0236] 52-Tone DRU-1: 26-Tone DRU-1 and 26-Tone DRU-6

[0237] 52-Tone DRU-2: 26-Tone DRU-2 and 26-Tone DRU-7

[0238] 52-Tone DRU-3: 26-Tone DRU-3 and 26-Tone DRU-8

[0239] 52-Tone DRU-4: 26-Tone DRU-4 and 26-Tone DRU-9

[0240] Here, each 52-tone DRU may be defined as a set of subcarrier indices corresponding to the 26-tone DRU indices defined in Embodiment 1-1, 1-2, 1-3, or 1-4.

[0241] Implementation 3

[0242] In this embodiment, various examples of configuring the subcarrier index of a 106-tone DRU are described.

[0243] For example, two 106-tone DRUs can be defined within a 20 MHz bandwidth. The subcarrier indices included in one 106-tone DRU can correspond to a set of subcarrier indices and two additional subcarrier indices included in two 52-tone DRUs. Furthermore, the subcarriers included in each 106-tone DRU can be defined to be as distributed as possible.

[0244] Implementation Method 3-1

[0245] The two additional subcarriers included in the 106-tone DRU may be two of the four null subcarriers (e.g., -122, -69, 69, 122) that are 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 may be included in the available subcarriers for the 106-tone DRU. Furthermore, the two additional subcarrier indices included in different 106-tone DRUs may not overlap with each other.

[0246] For example, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to embodiment 1-1 or 1-3, two 106-tone DRUs may be defined as follows.

[0247] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-3, and subcarrier index {-122,69}

[0248] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-4, and subcarrier index {-69,122}

[0249] Alternatively, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to embodiment 1-1 or 1-3, two 106-tone DRUs may be defined as follows.

[0250] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-3, and subcarrier index {-69,122}

[0251] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-4, and subcarrier index {-122,69}

[0252] Implementation Method 3-2

[0253] Similar to Embodiment 3-1, the two additional subcarriers included in the 106-tone DRU may be two of the four null subcarriers (eg, -122, -69, 69, 122) not used in the 26-tone DRU and the 52-tone DRU.

[0254] For example, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to embodiments 1-2 or 1-4, two 106-tone DRUs may be defined as follows.

[0255] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-3, and subcarrier index {-122,122}

[0256] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-4, and subcarrier index {-69,69}

[0257] Alternatively, when a 26-tone DRU corresponding to a 52-tone DRU is defined according to embodiments 1-2 or 1-4, two 106-tone DRUs may be defined as follows.

[0258] 106-tone DRU-1: 52-tone DRU-1, 52-tone DRU-3, and subcarrier index {-69,69}

[0259] 106-tone DRU-2: 52-tone DRU-2, 52-tone DRU-4, and subcarrier index {-122,122}

[0260] According to the DRU tone plan defined in various examples of the present disclosure described above, DRUs of the same / different sizes may be allocated to different STAs.

[0261] For example, when a specific RU index is indicated by the RU allocation field included in the SIG (e.g., U-SIG and / or UHR-SIG) field in DL OFDMA transmission, the STA receiving the PPDU can interpret that the data field in the corresponding PPDU is mapped on the subcarriers included in the DRU corresponding to the indicated RU index, and can decode the data field accordingly. Alternatively, when a specific RU index is indicated by the RU allocation subfield in the trigger frame, the STA receiving the trigger frame can send the TB PPDU to which the data field is mapped on the subcarriers included in the DRU corresponding to the indicated RU index. Here, the DRU corresponding to the indicated RU index can be determined based on the mapping rule between the RRU and the DRU.

[0262] Send and receive based on restricted DRU tone plan

[0263] Among the various DRU tone plans defined for 20 MHz bandwidth in the above example, the following describes a DRU tone plan that is limited by considering the tone position used in the STF field included in the PPDU that supports DRU (for example, the examples of the present disclosure can be applied to STF fields with other names, not limited to the names of UHR-STF and UHR).

[0264] The STF field may include a predetermined sequence mapped to a specific tone position. For example, the predetermined sequence may be M sequences defined as {-1,-1,-1,1,1,1,-1,1,1,-1,1,1,-1,1}.

[0265] For example, for 20 MHz transmission, the frequency domain sequence for PPDUs other than uplink TB PPDUs (eg, downlink PPDUs) may be defined as UHRS -112:16:112 ={M}*(1+j) / root(2). The value of the UHR-STF sequence for the null tone index 0 may be defined as 0. Here, UHRS a:b:c It means the coefficient of the UHR-STF on every b (or every b-th) subcarrier index from subcarrier index a to subcarrier index c, and the coefficients on other subcarrier indices are set to 0.

[0266] For example, for 20 MHz transmission, the frequency domain sequence for the uplink TB PPDU can be defined as UHRS -120:8:120 ={M,0,-M}*(1+j) / root(2).

[0267] In the present disclosure, the tone to which the UHR-STF sequence for a downlink PPDU is mapped is referred to as the first STF tone (e.g., 1x STF tone), and the tone to which the UHR-STF sequence for an uplink TB PPDU is mapped is referred to as the second STF tone (e.g., 2x STF tone).

[0268] According to the present disclosure, among the various DRU tone plans for the aforementioned 20 MHz channel, some DRUs may include tone positions that do not overlap with tone positions (or subcarrier indices) used for STFs. Within a PPDU, for tone positions in a DRU that do not overlap with STFs, there is a problem that AGC, etc., performed based on the corresponding STF may not be performed at the DRU tone position (i.e., power measurement may not be performed at the corresponding tone position). Therefore, the use of DRUs that include tone positions that do not overlap with STFs can be restricted.

[0269] Figure 13 is a diagram for explaining an example of a PPDU reception method based on a restricted DRU tone plan of a first STA according to the present disclosure.

[0270] In S1310 , the first STA may generate a PPDU including at least one field mapped on at least one DRU.

[0271] For example, at least one field may include a data field. In other words, the data field of the PPDU may be generated by mapping on at least one DRU of various sizes. In addition, the PPDU may also include a UHR-STF field.

[0272] For a PPDU associated with a downlink transmission, when at least one DRU includes any 26-tone DRU, the corresponding 26-tone DRU may be one of eight predefined 26-tone DRUs associated with a first STF tone, excluding a particular 26-tone DRU, among nine predefined 26-tone DRUs. Here, the nth (n=1, 2, ..., 9) 26-tone DRU may include the nth lowest subcarrier among available subcarriers in a 20 MHz channel. Furthermore, the nth (n=1, 2, ..., 9) 26-tone DRU may include every ninth subcarrier within each of at least one range, and one of the subcarriers may correspond to the nth lowest subcarrier. Among them, the first, second, third, fourth, sixth, seventh, eighth, and ninth 26-tone DRUs, excluding the fifth 26-tone DRU, may correspond to the eight predefined 26-tone DRUs associated with the first STF tone. For example, each of the eight predefined 26-tone DRUs may include a first STF tone for a 20 MHz channel. For example, a first STF tone (e.g., a 1x STF tone) for a 20 MHz channel may include every 16th subcarrier index in the range of subcarrier index -112 to subcarrier index 112.

[0273] For a PPDU associated with an uplink TB transmission, based on at least one DRU including any 26-tone DRU, the corresponding 26-tone DRU may be one of nine predefined 26-tone DRUs associated with a second STF tone. In other words, for uplink TB PPDU transmission, DRU restrictions based on STF considerations may not apply. For example, each of the nine predefined 26-tone DRUs may include a second STF tone for a 20 MHz channel. For example, the second STF tone for a 20 MHz channel (e.g., a 2x STF tone) may include every eighth subcarrier index in the range from subcarrier index -120 to subcarrier index 120.

[0274] Furthermore, when any one of the at least one range is from subcarrier index x to subcarrier index z, every 9th subcarrier index in such a range may be indicated as x:9:z.

[0275] For example, a first 26-tone DRU may include -121:9:-76, -66:9:-12, 4:9:67, and 77:9:113. A second 26-tone DRU may include -120:9:-75, -65:9:-11, 5:9:68, and 78:9:114. A third 26-tone DRU may include -119:9:-74, -64:9:-10, 6:9:60, and 70:9:115. A fourth 26-tone DRU may include -118:9:-73, -63:9:-9, 7:9:61, and 71:9:116. A fifth 26-tone DRU may include -117:9:-72, -62:9:-8, 8:9:62, and 72:9:117. The sixth 26-tone DRU may include -116:9:-71, -61:9:-7, 9:9:63, and 73:9:118. The seventh 26-tone DRU may include -115:9:-70, -60:9:-6, 10:9:64, and 74:9:119. The eighth 26-tone DRU may include -114:9:-78, -68:9:-5, 11:9:65, and 75:9:120. The ninth 26-tone DRU may include -113:9:-77, -67:9:-4, 12:9:66, and 76:9:121.

[0276] Based on the at least one DRU including any one 52-tone DRU, the corresponding 52-tone DRU may be one of four predefined 52-tone DRUs.

[0277] For example, a first 52-tone DRU may include subcarriers included in the first 26-tone DRU and the sixth 26-tone DRU. A second 52-tone DRU may include subcarriers included in the second 26-tone DRU and the seventh 26-tone DRU. A third 52-tone DRU may include subcarriers included in the third 26-tone DRU and the eighth 26-tone DRU. A fourth 52-tone DRU may include subcarriers included in the fourth 26-tone DRU and the ninth 26-tone DRU.

[0278] Based on the at least one DRU including any one 106-tone DRU, the corresponding 106-tone DRU may be one of two predefined 106-tone DRUs.

[0279] For example, a first 106-tone DRU may include a first group of null subcarriers 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 may include a second group of null subcarriers 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.

[0280] Here, when the indices of the four null subcarriers are -122, -69, 69, and 122, the first group may include subcarrier indices -122 and 69, and the second group may include subcarrier indices -69 and 122. Alternatively, the first group may include subcarrier indices -69 and 122, and the second group may include subcarrier indices -122 and 69.

[0281] 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.

[0282] In S1320 , the first STA may send a PPDU to at least one second STA over a bandwidth including a 20 MHz channel.

[0283] 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).

[0284] 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).

[0285] Figure 13 The method described in the example can be used by Figure 1 The first device 100 executes. For example, Figure 1 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 13 Examples or instructions of the methods described in the examples described below.

[0286] Figure 14is a diagram for explaining an example of a PPDU transmission method based on a restricted DRU tone schedule of a second STA according to the present disclosure.

[0287] In S1410 , the second STA may receive a PPDU including at least one field from the first STA over a bandwidth including a 20 MHz channel.

[0288] In S1420 , the second STA may decode at least one field mapped on at least one DRU.

[0289] For example, the second STA may determine the number and position of tones / subcarriers of at least one DRU to which at least one field (e.g., a data field) in the PPDU transmitted by the first STA is mapped based on the RU allocation information included in the corresponding PPDU or the RU allocation information included in the trigger frame that triggers the transmission of the corresponding PPDU. Based on this, the second STA may decode the at least one field mapped to the at least one DRU.

[0290] Various sizes (or number of tones / subcarriers) and positions of at least one DRU Figure 13 The examples are the same as those described in , so overlapping descriptions are omitted.

[0291] exist Figure 14 The method described in the example can be used by Figure 1 The second device 200 executes. For example, Figure 1 The at least one processor 202 of the second device 200 may be configured to receive a PPDU including at least one field from the first STA over a bandwidth including a 20 MHz channel and decode at least one field mapped on at least one DRU. In addition, the at least one memory 204 of the second device 200 may store instructions for executing the instructions when executed by the at least one processor 202. Figure 14 Examples or instructions of the methods described in the examples described below.

[0292] Figure 13 and Figure 14 Examples of may correspond to some of the various examples of the present disclosure. In the following, the examples including Figure 13 and Figure 14 Various examples of the present disclosure including examples of .

[0293] Implementation 4

[0294] The present embodiment relates to STF-based DRU restriction for downlink OFDMA transmission.

[0295] The above 1x STF can be used for DL ​​OFDMA transmission. In other words, the UHR-STF field included in the PPDU transmitted based on DL OFDMA can be generated by mapping the predetermined sequence to the 1x STF tone position. For the DRU tone plan in various embodiments for 20MHz transmission described above, the use of the restricted DRU index (including the tone that does not overlap with the STF tone) is as follows:

[0296] -For implementation 1-1, 26-tone DRU-5 is restricted for use,

[0297] Among the 52-tone DRUs in Embodiment 2 including the combination of the 26-tone DRUs based on Embodiment 1-1, there is no DRU whose use is restricted (i.e., all 52-tone DRUs are available),

[0298] In the 106-tone DRU in Embodiment 3 (or the 52-tone DRU in Embodiment 2 based on Embodiment 1-1) including a combination of the 26-tone DRU in Embodiment 1-1, there is no DRU whose use is restricted (i.e., all 106-tone DRUs are available),

[0299] - For implementation 1-2, 26-tone DRU-2, 26-tone DRU-4, 26-tone DRU-5, 26-tone DRU-7, and 26-tone DRU-9 are restricted for use,

[0300] The 52-tone DRU-2 and 52-tone DRU-4 in Embodiment 2, which include a combination of the 26-tone DRU based on Embodiment 1-2, are limited in use, and

[0301] The 106-tone DRU-2 in Embodiment 3, which includes a combination of the 26-tone DRU based on Embodiment 1-2 (or the 52-tone DRU based thereon in Embodiment 2), is restricted in use;

[0302] - For embodiment 2-1, 26-tone DRU-3, 26-tone DRU-4, 26-tone DRU-6 and 26-tone DRU-7 are restricted in use,

[0303] Among the 52-tone DRUs including the combination of the 26-tone DRUs based on the embodiment 2-1 in embodiment 2, there is no DRU whose use is restricted (ie, all 52-tone DRUs are available),

[0304] Among the 106-tone DRUs in Embodiment 3 including the combination of the 26-tone DRU based on Embodiment 2-1 (or the 52-tone DRU based thereon in Embodiment 2), there is no DRU whose use is restricted (i.e., all 106-tone DRUs are available); and

[0305] - For embodiment 2-2, 26-tone DRU-3, 26-tone DRU-4, 26-tone DRU-6, 26-tone DRU-7, 26-tone DRU-8 and 26-tone DRU-9 are restricted in use,

[0306] The 52-tone DRU-3 and 52-tone DRU-4 in Embodiment 2, which include a combination of the 26-tone DRU based on Embodiment 2-2, are limited in use.

[0307] Among the 106-tone DRUs including the combination of the 26-tone DRU based on Embodiment 2-2 (or the 52-tone DRU based thereon in Embodiment 2) in Embodiment 3, there is no DRU whose use is restricted (ie, all 106-tone DRUs are available).

[0308] Implementation 5

[0309] This embodiment relates to STF-based DRU restriction for TB PPDU transmission.

[0310] The above 2x STF can be used for TB transmission. In other words, the UHR-STF field included in the PPDU transmitted based on the trigger frame can be generated by mapping the predetermined sequence to the 2x STF tone position. For the DRU tone plan in various embodiments for 20MHz transmission described above, the use of the restricted DRU index (including the tone that does not overlap with the STF tone) is as follows:

[0311] - In embodiment 1-1, there is no DRU whose usage is restricted among all 26-tone DRUs (i.e., all 26-tone DRUs are available),

[0312] Among the 52-tone DRUs in Embodiment 2 including the combination of the 26-tone DRUs based on Embodiment 1-1, there is no DRU whose use is restricted (i.e., all 52-tone DRUs are available),

[0313] Among the 106-tone DRUs including the combination of the 26-tone DRU based on Embodiment 1-1 (or the 52-tone DRU based thereon in Embodiment 2) in Embodiment 3, there is no DRU whose use is restricted (i.e., all 106-tone DRUs are available),

[0314] - For implementations 1-2, 26-tone DRU-4 is restricted for use,

[0315] Among the 52-tone DRUs in Embodiment 2 including the combination of 26-tone DRUs based on Embodiments 1-2, there is no DRU whose use is restricted (ie, all 52-tone DRUs are available).

[0316] Among the 106-tone DRUs including the combination of the 26-tone DRUs based on Embodiments 1-2 (or the 52-tone DRUs based on Embodiment 2 in Embodiment 2), there is no DRU whose use is restricted (i.e., all 106-tone DRUs are available).

[0317] - For embodiment 2-1, 26-tone DRU-3, 26-tone DRU-4, 26-tone DRU-6 and 26-tone DRU-7 are restricted in use,

[0318] Among the 52-tone DRUs including the combination of the 26-tone DRUs based on the embodiment 2-1 in embodiment 2, there is no DRU whose use is restricted (ie, all 52-tone DRUs are available),

[0319] Among the 106-tone DRUs in Embodiment 3 including the combination of the 26-tone DRU based on Embodiment 2-1 (or the 52-tone DRU based thereon in Embodiment 2), there is no DRU whose use is restricted (i.e., all 106-tone DRUs are available); and

[0320] - For embodiment 2-2, 26-tone DRU-3, 26-tone DRU-4, 26-tone DRU-6, 26-tone DRU-7, 26-tone DRU-8 and 26-tone DRU-9 are restricted in use,

[0321] The 52-tone DRU-3 and 52-tone DRU-4 in Embodiment 2, which include a combination of the 26-tone DRU based on Embodiment 2-2, are limited in use.

[0322] Among the 106-tone DRUs in Embodiment 3 including the combination of the 26-tone DRU based on Embodiment 2-2 (or the 52-tone DRU based thereon in Embodiment 2), there is no DRU whose use is restricted (i.e., all 106-tone DRUs are available),

[0323] In the above examples of tone plans whose usage is restricted by considering STF, embodiment 1-1 has the least number of DRU tone plans whose usage is restricted compared to other embodiments (i.e., only 26-tone DRU-5 is restricted and all remaining DRU tone plans are available for DL ​​OFDM transmission).

[0324] Unlike existing WLAN systems that only utilize RRUs, the present disclosure improves resource utilization efficiency when supporting the use of DRUs by scheduling transmission / reception of at least one field of a PPDU based on DRU tones of various sizes applicable to a 20 MHz bandwidth PPDU. Furthermore, by clearly defining the DRU and limiting its use based on its relationship to the STF tone, the results of power measurement using the STF, such as AGC, can be easily applied.

[0325] The above-mentioned embodiments are to combine the elements and features of the present disclosure in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be considered as optional. Each element or feature can be implemented in a form not combined with other elements or features. In addition, the embodiments of the present disclosure may include some elements and / or features of the combination. The order of the operations described in the embodiments of the present disclosure may be changed. Some elements or features of an embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. Obviously, the embodiments may include claims that do not have a clear reference relationship in the combined claims, or may be included as new claims through modification after application.

[0326] It is clear to those skilled in the relevant art that the present disclosure may be implemented in other specific forms within the scope of the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted restrictively in every aspect, but should be considered as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all variations within the scope of equivalents of the present disclosure are included within the scope of the present disclosure.

[0327] The scope of the present disclosure includes software or machine executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations in accordance with the methods of various embodiments in a device or computer, and non-transitory computer-readable media that enable software or commands, etc. to be stored and executable in a device or computer. Commands that can be used to program a processing system that performs the features described in this disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in this disclosure can be implemented by using a computer program product that includes such a storage medium. The storage medium may include high-speed random access memory, such as, but not limited to, DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, and it may include non-volatile memory, such as, for example, 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 located away 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 this disclosure may be stored in any machine-readable medium to control the hardware of a processing system and may be integrated into software and / or firmware that allows the processing system to utilize the results from the embodiments of this disclosure and interact with other mechanisms. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0328] Industrial Applicability

[0329] The method proposed in the present disclosure is mainly described based on an example of application to a system based on IEEE 802.11 (5G system), but can be applied to various WLAN 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 at least one field, wherein the at least one field is mapped on at least one distributed resource unit (DRU); and sending the PPDU to at least one second STA over a bandwidth including a 20 MHz channel, Wherein, for the PPDU associated with downlink transmission, based on the at least one DRU including a 26-tone DRU, the 26-tone DRU is one of 8 predefined 26-tone DRUs associated with the first short training field STF tone among 9 predefined 26-tone DRUs, excluding a specific 26-tone DRU.

2. The method according to claim 1, wherein in, An nth 26-tone DRU is defined as every 9th subcarrier in each of at least one range, the nth 26-tone DRU including the nth lowest subcarrier among the available subcarriers in the 20 MHz channel, n=1, 2, ..., 9, and The particular one 26-tone DRU is the fifth 26-tone DRU.

3. The method according to claim 2, wherein: Each of the eight predefined 26-tone DRUs includes the first STF tone for the 20 MHz channel, and The first STF tones for the 20 MHz channel include every 16th subcarrier index in the range from subcarrier index -112 to subcarrier index 112.

4. The method according to claim 1, wherein For the PPDU associated with uplink triggered-based TB transmission, based on the at least one DRU including the 26-tone DRU, the 26-tone DRU is a predefined 26-tone DRU associated with a second STF tone among the 9 predefined 26-tone DRUs.

5. The method according to claim 4, wherein Each of the nine predefined 26-tone DRUs includes the second STF tone for the 20 MHz channel, and The second STF tones for the 20 MHz channel include every 8th subcarrier index in the range from subcarrier index -120 to subcarrier index 120.

6. The method according to claim 2, wherein: The available subcarriers are subcarriers excluding 7 DC subcarriers, 4 null subcarriers and 11 guard subcarriers among the 256 subcarriers in the 20 MHz channel.

7. The method according to claim 6, wherein: Based on one range of the at least one range corresponding to from subcarrier index x to subcarrier index z, every 9th subcarrier index in the one range is indicated as x:9:z, The first 26-tone DRU includes -121:9:-76, -66:9:-12, 4:9:67, and 77:9:

113. The second 26-tone DRU includes -120:9:-75, -65:9:-11, 5:9:68, and 78:9:114, The third 26-tone DRU includes -119:9:-74, -64:9:-10, 6:9:60, and 70:9:115, The fourth 26-tone DRU includes -118:9:-73, -63:9:-9, 7:9:61, and 71:9:116, The fifth 26-tone DRU includes -117:9:-72, -62:9:-8, 8:9:62, and 72:9:117, The sixth 26-tone DRU includes -116:9:-71, -61:9:-7, 9:9:63, and 73:9:118, The seventh 26-tone DRU includes -115:9:-70, -60:9:-6, 10:9:64, and 74:9:

119. The eighth 26-tone DRU includes -114:9:-78, -68:9:-5, 11:9:65, and 75:9:120, and The ninth 26-tone DRU includes -113:9:-77, -67:9:-4, 12:9:66, and 76:9:

121.

8. The method according to claim 7, wherein: Based on the at least one DRU comprising a 52-tone DRU, the 52-tone DRU being 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 the second 26-tone DRU and the seventh 26-tone DRU, a third 52-tone DRU including 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.

9. The method according to claim 8, wherein Based on the at least one DRU 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.

10. The method according to claim 9, wherein: The indices based on the 4 empty subcarriers are -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.

11. The method according to claim 1, wherein Based on the PPDU being a downlink PPDU, indicating the at least one DRU for the downlink PPDU based on resource unit RU allocation information included in the downlink PPDU, or Based on the PPDU being an uplink TB PPDU, the at least one DRU for the uplink TB PPDU is indicated based on RU allocation information included in a trigger frame that triggers transmission of the uplink TB PPDU.

12. The method according to claim 1, wherein The at least one field comprises a data field, and The PPDU also includes a UHR-STF field.

13. 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 at least one field, wherein the at least one field is mapped on at least one distributed resource unit (DRU); and transmitting, by the at least one transceiver, the PPDU to at least one second STA over a bandwidth including a 20 MHz channel, Wherein, for the PPDU associated with downlink transmission, based on the at least one DRU including a 26-tone DRU, the 26-tone DRU is one of 8 predefined 26-tone DRUs among 9 predefined 26-tone DRUs excluding a specific 26-tone DRU.

14. A method performed by a second station (STA) in a wireless local area network (WLAN) system, the method comprising the following steps: receiving, from a first STA over a bandwidth including a 20 MHz channel, a physical layer protocol data unit (PPDU) including at least one field; as well as decoding the at least one field mapped on at least one distributed resource unit DRU, Wherein, for the PPDU associated with downlink transmission, based on the at least one DRU including a 26-tone DRU, the 26-tone DRU is one of 8 predefined 26-tone DRUs among 9 predefined 26-tone DRUs excluding a specific 26-tone DRU.

15. 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: receiving, by the at least one transceiver, a physical layer protocol data unit (PPDU) including at least one field from a first STA over a bandwidth including a 20 MHz channel; and decoding the at least one field mapped on at least one distributed resource unit DRU, Wherein, for the PPDU associated with downlink transmission, based on the at least one DRU including a 26-tone DRU, the 26-tone DRU is one of 8 predefined 26-tone DRUs among 9 predefined 26-tone DRUs excluding a specific 26-tone DRU.

16. 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 12 upon execution by the at least one processor.

17. 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 perform the method according to any one of claims 1 to 12 in a wireless local area network (WLAN) system.

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