Method and device for PPDU transmission and reception in wireless LAN system

Abstract

Disclosed are a method and a device for PPDU transmission and reception in a wireless LAN system. A method performed by an STA according to one embodiment disclosed herein comprises the steps of: receiving a trigger frame from an AP; and transmitting a PPDU to the AP on the basis of the trigger frame, wherein the trigger frame includes a distributed-tone resource unit (DRU) / regular resource unit (RRU) indication field indicating whether DRU transmission or RRU transmission is requested for each frequency subblock for the PPDU, and a guard interval (GI) and LTF type field indicating the GI and LTF type of the PPDU, and the GI and LTF type indicated by the value of the GI and LTF type field is defined on the basis of the indication of the DRU / RRU indication field.

Description

Method and device for transmitting and receiving PPDU in a wireless LAN system

[0001] The present disclosure relates to a method and apparatus for transmitting and receiving a physical protocol data unit (PPDU) in a Wireless Local Area Network (WLAN) system.

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

[0003] To provide an improved wireless communication environment, advanced technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for Multiple Input Multiple Output (MIMO) supporting increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, as well as technologies for multiple access points (AP) coordination, are being researched. In particular, various technologies are being studied to support traffic with low latency or real-time characteristics. Furthermore, new technologies to support ultra-high reliability (UHR), including improvements or extensions of EHT technology, are being discussed.

[0004] The technical problem of the present disclosure is to provide a method and apparatus for transmitting and receiving a PPDU comprising a distributed-tone resource unit (DRU) composed of discontinuous distributed subcarriers.

[0005] Additionally, an additional technical object of the present disclosure is to provide a method for indicating / determining a guard interval (GI) and an LTF type for a PPDU transmission including a DRU (or including a DRU and an RRU).

[0006] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below.

[0007] A method performed by a station (STA) according to one aspect of the present disclosure may include: receiving a trigger frame from an access point (AP); and transmitting a physical protocol data unit (PPDU) to the AP based on the trigger frame. The trigger frame may include a DRU / RRU indication field indicating whether a distributed-tone resource unit (DRU) transmission or a regular resource unit (RRU) transmission is requested for the PPDU by frequency subblock, and a GI and LTF type field indicating a guard interval (GI) and a long training field (LTF) type of the PPDU, and based on the indication of the DRU / RRU indication field, the GI and LTF types indicated by the values ​​of the GI and LTF type fields may be defined.

[0008] A method performed by an access point (AP) according to an additional aspect of the present disclosure may include: transmitting a trigger frame to a station (STA); and receiving a physical protocol data unit (PPDU) from the STA based on the trigger frame. The trigger frame may include a DRU / RRU indication field indicating whether a distributed-tone resource unit (DRU) transmission or a regular resource unit (RRU) transmission is requested for the PPDU by frequency subblock, and a GI and LTF type field indicating a guard interval (GI) and a long training field (LTF) type of the PPDU, and based on the indication of the DRU / RRU indication field, the GI and LTF types indicated by the values ​​of the GI and LTF type fields may be defined.

[0009] According to the present disclosure, transmission power can be improved by using a DRU, and accordingly, transmission throughput can be increased and coverage can be improved.

[0010] In addition, according to the present disclosure, GI overhead can be reduced in PPDU transmission including DRU to improve transmission throughput.

[0011] In addition, according to the present disclosure, by setting an LTF type more suitable for PPDU transmission including a DRU, the channel state can be estimated more accurately and frequency and timing synchronization performance can be improved.

[0012] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0013] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and explain the technical features of the present disclosure together with the detailed description.

[0014] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0015] FIG. 2 is a drawing showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

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

[0017] FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied.

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

[0019] FIG. 6 is a drawing for illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure may be applied.

[0020] FIG. 7 is a drawing illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure may be applied.

[0021] FIG. 8 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0022] FIG. 9 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0023] FIG. 10 is a drawing illustrating an example of a distributed-tone RU in a wireless LAN system to which the present disclosure may be applied.

[0024] FIG. 11 is a drawing illustrating a DRU operation mode according to one embodiment of the present disclosure.

[0025] FIG. 12 illustrates a trigger frame for DRU signaling according to one embodiment of the present disclosure.

[0026] FIG. 13 illustrates DRU signaling according to one embodiment of the present disclosure.

[0027] FIG. 14 is a diagram showing an exemplary format of a trigger frame in a wireless LAN system to which the present disclosure may be applied.

[0028] FIG. 15 illustrates a DRU / RRU indication subfield format in a wireless LAN system to which the present disclosure may be applied.

[0029] FIG. 16 is a drawing illustrating a PPDU format according to one embodiment of the present disclosure.

[0030] FIG. 17 illustrates the operation of an STA device for a PPDU transmission and reception method according to one embodiment of the present disclosure.

[0031] FIG. 18 illustrates the operation of an AP device for a PPDU transmission and reception method according to one embodiment of the present disclosure.

[0032] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below, together with the accompanying drawings, is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure may be practiced. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the art will know that the present disclosure may be practiced without such specific details.

[0033] In some cases, to avoid obscuring the concept of the present disclosure, known structures and devices may be omitted or illustrated in the form of a block diagram focusing on the core functions of each structure and device.

[0034] In the present disclosure, when a component is described as being “connected,” “combined,” or “joined” with another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, in the present disclosure, the terms “comprising” or “having” specify the presence of the mentioned features, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, actions, elements, components, and / or groups thereof.

[0035] In the present disclosure, terms such as "first," "second," etc. are used solely for the purpose of distinguishing one component from another and are not used to limit the components, nor do they limit the order or importance of the components unless specifically stated otherwise. Accordingly, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and likewise, a second component in one embodiment may be referred to as a first component in another embodiment.

[0036] The terms used in this disclosure are for the description of specific embodiments and are not intended to limit the claims. As used in the description of embodiments and in the appended claims, the singular form is intended to include the plural form unless the context clearly indicates otherwise. The term "and / or" as used in this disclosure may refer to any one of the related enumerated items, or refers to and includes any and all possible combinations of two or more of them. Additionally, the " / " between words in this disclosure has the same meaning as "and / or" unless otherwise noted.

[0037] The embodiments of the present disclosure may be applied to various wireless communication systems. For example, the embodiments of the present disclosure may be applied to wireless LAN systems. For example, the embodiments of the present disclosure may be applied to wireless LANs based on IEEE 802.11a / g / n / ac / ax / be standards. Furthermore, the embodiments of the present disclosure may be applied to wireless LANs based on newly proposed IEEE 802.11bn (or UHR) standards. Additionally, the embodiments of the present disclosure may be applied to wireless LANs based on next-generation standards following IEEE 802.11bn. Furthermore, the embodiments of the present disclosure may be applied to cellular wireless communication systems. For example, they may be applied to cellular wireless communication systems based on LTE (Long Term Evolution) series technologies and 5G NR (New Radio) series technologies of 3GPP (3rd Generation Partnership Project) standards.

[0038] The following describes the technical features to which the examples of the present disclosure may be applied.

[0039] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0040] The first device (100) and the second device (200) exemplified in FIG. 1 may be replaced with various terms such as terminal, wireless device, WTRU (Wireless Transmit Receive Unit), UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), MSS (Mobile Subscriber Unit), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), or simply user. Additionally, the first device (100) and the second device (200) may be replaced with various terms such as access point (AP), BS (Base Station), fixed station, Node B, BTS (base transceiver system), network, AI (Artificial Intelligence) system, RSU (road side unit), repeater, router, relay, gateway, etc.

[0041] The device (100, 200) exemplified in FIG. 1 may be referred to as a station (STA). For example, the device (100, 200) exemplified in FIG. 1 may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, or a receiving STA. For example, the STA (110, 200) may perform the role of an access point (AP) or a non-AP. That is, in the present disclosure, the STA (110, 200) may perform the functions of an AP and / or a non-AP. If the STA (110, 200) performs the AP function, it may simply be referred to as an AP, and if the STA (110, 200) performs the non-AP function, it may simply be referred to as a STA. Additionally, in the present disclosure, the AP may also be indicated as an AP STA.

[0042] Referring to FIG. 1, the first device (100) and the second device (200) can transmit and receive wireless signals through various wireless LAN technologies (e.g., IEEE 802.11 series). The first device (100) and the second device (200) may include interfaces for the medium access control (MAC) layer and the physical layer (PHY) that comply with the specifications of the IEEE 802.11 standard.

[0043] In addition, the first device (100) and the second device (200) may additionally support various communication standards other than wireless LAN technology (e.g., 3GPP LTE series, 5G NR series standards, etc.). In addition, the device of the present disclosure may be implemented as various devices such as mobile phones, vehicles, personal computers, AR (Augmented Reality) equipment, VR (Virtual Reality) equipment, etc. Furthermore, the STA of the present specification may support various communication services such as voice calls, video calls, data communication, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).

[0044] The first device (100) includes one or more processors (102) and one or more memories (104), and may additionally include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memory (104) and / or transceivers (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (102) may process information within the memory (104) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through the transceiver (106) and then store information obtained from the signal processing of the second information / signal in the memory (104). Memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, memory (104) may store software code including instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this disclosure. Here, the processor (102) and memory (104) may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals through one or more antennas (108). The transceiver (106) may include a transmitter and / or receiver. The transceiver (106) may be combined with an RF (Radio Frequency) unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0045] The second device (200) includes one or more processors (202) and one or more memories (204), and may additionally include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memory (204) and / or transceivers (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal 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 containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed 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 through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be used in combination with an RF unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0046] Hereinafter, hardware elements of the device (100, 200) will be described in more detail. Although not limited thereto, 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 Protocol Data Units (PDUs) and / or Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure. One or more processors (102, 202) may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this disclosure and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., a baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this disclosure.

[0047] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0048] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0049] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of the present disclosure to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., disclosed in the present disclosure from one or more other devices. For example, one or more transceivers (106, 206) may be connected to one or more processors (102, 202) and may transmit and receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure through one or more antennas (108, 208). In this disclosure, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0050] For example, one of the STAs (100, 200) may perform the intended operation of an AP, and the other of the STAs (100, 200) may perform the intended operation of a non-AP STA. For example, the transceiver (106, 206) of FIG. 1 may perform the operation of transmitting and receiving signals (e.g., packets or PPDU (Physical Layer Protocol Data Unit) according to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). Additionally, the operation of generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals by various STAs in the present disclosure may be performed by the processor (102, 202) of FIG. 1. For example, an example of an operation to generate a transmission and reception signal or to perform data processing or operations in advance for a transmission and reception signal may include: 1) an operation to determine / acquire / configure / operate / decode / encode bit information of fields (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in the PPDU; 2) an operation to determine / configure / acquire time resources or frequency resources (e.g., subcarrier resources) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 3) an operation to determine / configure / acquire specific sequences (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 4) power control operations and / or power saving operations applied to the STA; and 5) operations related to determining / acquiring / configuring / operating / decoding / encoding of an ACK signal. In addition, various information (e.g., information related to fields, subfields, control fields, parameters, power, etc.) used by various STAs for determining / acquiring / configuring / calculating / decoding / encoding transmission and reception signals in the following example can be stored in the memory (104, 204) of FIG. 1.

[0051] In the following, the downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs, packets, signals, etc., can be transmitted and received through the downlink. In downlink communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. The uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs, packets, signals, etc., can be transmitted and received through the uplink. In uplink communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

[0052] FIG. 2 is a drawing showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0053] The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports STA mobility transparent to the upper layer can be provided. A Basic Service Set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 exemplarily illustrates the existence of two BSSs (BSS1 and BSS2) and the inclusion of two STAs as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). In Figure 2, the ellipse representing the BSS can also be understood as representing the coverage area where the STAs included in the corresponding BSS maintain communication. This area can be referred to as a Basic Service Area (BSA). If a STA moves outside the BSA, it becomes unable to communicate directly with other STAs within that BSA.

[0054] Excluding the DS illustrated in Fig. 2, the most basic type of BSS in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For instance, assuming other components are omitted, a BSS1 composed of only STA1 and STA2, or a BSS2 composed of only STA3 and STA4, can each be considered a representative example of an IBSS. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, this type of wireless LAN is not configured through pre-planning but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. In other words, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and since connections to distributed systems (DS) are not allowed, they form a self-contained network.

[0055] The membership of an STA in a BSS can be dynamically changed by the STA being turned on or off, or by the STA entering or leaving the BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, an STA must be associated with the BSS. This association can be configured dynamically and may include the use of a Distribution System Service (DSS).

[0056] In a wireless LAN, the direct STA-to-STA distance may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in others, communication between STAs over longer distances may be required. To support extended coverage, a distributed system (DS) may be configured.

[0057] DS refers to a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component in 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). In this regard, the Wireless Medium (WM) and the DSM can be logically distinguished. Each logical medium is used for a different purpose and is utilized by different components. These media are not limited to being identical or different. The flexibility of the wireless LAN structure (DS structure or other network structure) can be explained by the fact that multiple media are logically distinct in this way. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be specified independently by the physical characteristics of each implementation.

[0058] DS can support mobile devices by providing seamless integration of multiple BSSs and providing logical services necessary for handling addresses to destinations. Additionally, DS may include a component called a portal that acts as a bridge for connecting the wireless LAN with another network (e.g., IEEE 802.X).

[0059] An AP refers to an entity that enables access to a DS via a WM for combined non-AP STAs and also possesses the functionality of an STA. Data movement between a BSS and a DS can be performed through the AP. For example, STA2 and STA3 shown in FIG. 2 possess the functionality of an STA and provide the ability for combined non-AP STAs (STA1 and STA4) to access a DS. Furthermore, since all APs fundamentally correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM and the address used by the AP for communication on the DSM do not necessarily have to be the same. A BSS composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0060] Data transmitted from one of the STA(s) coupled to the AP to the STA address of the AP can always be received at an uncontrolled port and processed by an IEEE 802.1X port access entity. Additionally, if the controlled port is authenticated, the transmitted data (or frame) can be forwarded to the DS.

[0061] In addition to the structure of the aforementioned DS, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0062] An ESS refers to a network of arbitrary size and complexity composed of DSs and BSSs. An ESS can correspond to a set of BSSs connected to a single DS. However, an ESS does not contain a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in a single ESS can have the same Service Set Identification (SSID). The SSID is distinct from the BSSID, which is the identifier for the BSS.

[0063] In wireless LAN systems, no assumptions are made regarding the relative physical locations of BSSs, and all of the following forms are possible. BSSs may partially overlap, which is a form commonly used to provide continuous coverage. Additionally, BSSs may not be physically connected, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs may be located in the same physical location, which can be used to provide redundancy. Also, one (or more) IBSS or ESS networks may physically exist in the same space as one (or more) ESS networks. This may apply to ESS network forms such as when an ad-hoc network operates at a location where an ESS network exists, when wireless networks that physically overlap are configured by different organizations, or when two or more different access and security policies are required at the same location.

[0064] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0065] In order for an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and go through authentication procedures for security. The link setup process can also be referred to as the session initiation process or the session setup process. Additionally, the processes of discovery, authentication, association, and security setup in the link setup process can be collectively referred to as the association process.

[0066] In step S310, the STA may perform a network discovery operation. The network discovery operation may include the STA's scanning operation. That is, in order for the STA to access a network, it must find a network it can join. Before joining a wireless network, the STA must identify a compatible network, and the process of identifying networks existing in a specific area is called scanning.

[0067] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, the STA performing the scanning moves between channels to search for nearby APs, transmits a probe request frame, and waits for a response. The responder transmits a probe response frame as a response to the probe request frame to the STA that transmitted the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame from the BSS of the channel being scanned. In a BSS, the AP becomes the responder because it transmits the beacon frame; however, in an IBSS, the responder is not constant because STAs within the IBSS take turns transmitting the beacon frame. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning in the same way (i.e., transmit and receive probe request / response on channel 2).

[0068] Although not illustrated in FIG. 3, the scanning operation may be performed using a passive scanning method. In passive scanning, the STA performing the scanning waits for a beacon frame while switching between channels. A beacon frame is one of the management frames defined in IEEE 802.11, which is periodically transmitted to announce the presence of a wireless network and to allow the scanning STA to find the wireless network and join it. In a BSS, the AP performs the role of periodically transmitting beacon frames, and in an IBSS, the STAs within the IBSS take turns transmitting beacon frames. When the scanning STA receives a beacon frame, it stores the information about the BSS included in the beacon frame and records the beacon frame information in each channel while moving to another channel. The STA that receives the beacon frame stores the BSS-related information included in the received beacon frame and moves to the next channel, and can perform scanning in the next channel in the same way. When comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0069] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation in step S340 described later.

[0070] The authentication process involves the STA sending an authentication request frame to the AP, and the AP sending an authentication response frame to the STA in response. The authentication frame used in the authentication request / response corresponds to a management frame.

[0071] The authentication frame may include information regarding the authentication algorithm number, authentication transaction sequence number, status code, challenge text, Robust Security Network (RSN), Finite Cyclic Group, etc. These are some examples of information that may be included in the authentication request / response frame, and they may be replaced with other information or additional information may be included.

[0072] The STA can send an authentication request frame to the AP. Based on the information contained in the received authentication request frame, the AP can determine whether to allow authentication for the STA. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0073] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the STA transmitting an association request frame to the AP, and in response, the AP transmitting an association response frame to the STA.

[0074] For example, the association request frame may include information regarding various capabilities, beacon listen interval, service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information regarding various capabilities, status code, Association ID (AID), supported rates, Enhanced Distributed Channel Access (EDCA) parameter set, Received Channel Power Indicator (RCPI), Received Signal to Noise Indicator (RSNI), mobility domain, timeout interval (e.g., association comeback time), overlapping BSS scan parameters, TIM broadcast response, Quality of Service (QoS) map, etc. These are some examples of information that may be included in a combined request / response frame, and may be replaced with other information or additional information may be included.

[0075] After the STA is successfully joined to the network, a security setup process can be performed in step S340. The security setup process in step S340 may be described as an authentication process through RSNA (Robust Security Network Association) requests / responses, and the authentication process in step S320 may be referred to as the first authentication process, and the security setup process in step S340 may simply be referred to as the authentication process.

[0076] The security setup process of step S340 may include, for example, a private key setup process through a 4-way handshake via an EAPOL (Extensible Authentication Protocol over LAN) frame. Additionally, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

[0077] FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied.

[0078] In wireless LAN systems, the basic access mechanism for MAC (Medium Access Control) is the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism is also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, and it basically employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA may perform Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time interval (e.g., DIFS (DCF Inter-Frame Space)) before starting transmission. If the sensing result determines that the medium is in an idle status, it starts transmitting a frame through that medium. On the other hand, if the medium is detected to be occupied or busy, the AP and / or STA may not start its own transmission but wait by setting a delay period for medium access (e.g., a random backoff period) before attempting to transmit a frame. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

[0079] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). The HCF is based on the aforementioned Point Coordination Function (PCF). The PCF is a polling-based synchronous access method that periodically polls to ensure all receiving APs and / or STAs can receive data frames. Furthermore, the HCF includes Enhanced Distributed Channel Access (EDCA) and Controlled Channel Access (HCCA). EDCA is a contention-based access method for a provider to offer data frames to multiple users, while HCCA uses a non-contention-based channel access method utilizing a polling mechanism. Additionally, the HCF includes a media access mechanism to improve the Quality of Service (QoS) of the wireless LAN and can transmit QoS data during both the Contention Period (CP) and the Contention-Free Period (CFP).

[0080] With reference to FIG. 4, the operation based on the random backoff period is described. When a medium in an occupied / busy state changes to an idle state, multiple STAs may attempt to transmit data (or frames). As a measure to minimize collisions, each STA may select a random backoff count and attempt transmission after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​in the range from 0 to CW. Here, CW is the Contention Window parameter value. The CW parameter is given an initial value of CWmin, but in the case of transmission failure (e.g., failure to receive an ACK for a transmitted frame), it may take a value twice that amount. When the CW parameter value becomes CWmax, data transmission may be attempted while maintaining the CWmax value until data transmission is successful; if data transmission is successful, it is reset to the CWmin value. The values ​​of CW, CWmin, and CWmax are 2 n It is desirable to set it to -1 (n=0, 1, 2, ...).

[0081] When the random backoff process begins, the STA continues to monitor the media while counting down the backoff slots according to the determined backoff count value. When the media is monitored as occupied, it stops the countdown and waits, and when the media becomes idle, it resumes the remaining countdown.

[0082] In the example of Fig. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 confirms that the medium is idle for DIFS and can immediately transmit the frame. The remaining STAs monitor whether the medium is occupied or busy and wait. Meanwhile, data to be transmitted may also arise from each of STA1, STA2, and STA5, and each STA can perform a countdown of the backoff slot according to a random backoff count value selected by each after waiting for DIFS when the medium is monitored to be idle. Assume the case where STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. That is, this exemplifies a case where, at the point when STA2 finishes the backoff count and starts transmitting the frame, the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1. STA1 and STA5 pause the countdown briefly and wait while STA2 occupies the medium. When STA2's possession ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the paused backoff count. That is, they can start transmitting a frame after counting down the remaining backoff slots corresponding to the remaining backoff time. Since STA5's remaining backoff time was shorter than STA1's, STA5 starts transmitting the frame. While STA2 is occupying the medium, data to be transmitted may also be generated by STA4. From STA4's perspective, when the medium becomes idle, it waits for DIFS, performs a countdown based on a random backoff count value selected by itself, and can start transmitting a frame. The example in Figure 4 illustrates a case where STA5's remaining backoff time happens to match STA4's random backoff count value; in this case, a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 receives an ACK, resulting in a failure to transmit data.In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. STA1 waits while the medium is occupied due to transmission by STA4 and STA5, and when the medium becomes idle, it waits for DIFS, and then can start transmitting frames after the remaining backoff time has passed.

[0083] As shown in the example in Fig. 4, a data frame is a frame used for transmitting data that is forwarded to an upper layer, and can be transmitted after a backoff performed after the elapsed time of DIFS from when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information that is not forwarded to an upper layer, and is transmitted after a backoff performed after the elapsed time of an IFS such as DIFS or PIFS (Point coordination function IFS). Subtypes of management frames include Beacon, Association request / response, re-association request / response, probe request / response, and authentication request / response. A control frame is a frame used to control access to the medium. Subtype frames of control frames include RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), NDP Announcement (null data packet announcement), and Trigger. If a control frame is not an acknowledgment frame of a previous frame, it is transmitted after a backoff performed after the elapsed DIFS; if it is an acknowledgment frame of a previous frame, it is transmitted after the elapsed SIFS (short IFS) without a backoff. The type and subtype of a frame can be identified by the type field and subtype field within the Frame Control (FC) field.

[0084] A QoS (Quality of Service) STA can transmit a frame after backoff, which is performed after the passage of the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC). Here, the frame for which AIFS[i] can be used can be a data frame or a management frame, and can also be a control frame rather than a response frame.

[0085] FIG. 5 is a diagram illustrating a CSMA / CA-based frame transmission operation to which the present disclosure may be applied.

[0086] As previously mentioned, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, where the STA directly senses the medium. Virtual carrier sensing is intended to mitigate problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the STA's MAC can utilize the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available, provided that the STA currently using or authorized to use the medium is using it. Therefore, the value set as the NAV corresponds to the period during which the medium is scheduled to be used by the STA transmitting the frame, and the STA receiving the NAV value is prohibited from accessing the medium during that period. For example, the NAV can be set based on the value of the "duration" field in the frame's MAC header.

[0087] In the example of FIG. 5, it is assumed that STA1 intends to transmit data to STA2, and STA3 is located in a position where it can overhear part or all of the frames transmitted and received between STA1 and STA2.

[0088] In order to reduce the possibility of collisions between multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism utilizing RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA1 may be a hidden node to STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA2 may be a hidden node to STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, it is possible to prevent a STA outside the transmission range of either STA1 or STA2, or a STA outside the carrier sensing range for transmission from STA1 or STA3, from attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0089] Specifically, STA1 can determine whether the 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 magnitude or signal correlation detected in the channel. Additionally, in terms of virtual carrier sensing, STA1 can determine the channel occupancy state using a NAV (network allocation vector) timer.

[0090] If the channel is idle during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. If STA2 receives the RTS frame, it can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0091] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) using the duration information included in the RTS frame. Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + data frame + SIFS + ACK frame) using the duration information included in the CTS frame. That is, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, it can set a NAV accordingly. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0092] If STA1 receives a CTS frame from STA2, it may transmit a data frame to STA2 after SIFS from the time the reception of the CTS frame is completed. If STA2 successfully receives the data frame, it may transmit an ACK frame to STA1 as an acknowledgment to the data frame after SIFS. STA3 may determine whether the channel is in use through carrier sensing when the NAV timer expires. If STA3 determines that the channel is not in use by another terminal during DIFS from the time the NAV timer expires, it may attempt channel access after a contention window (CW) based on random backoff has passed.

[0093] FIG. 6 is a drawing for illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure may be applied.

[0094] Based on instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MPDU (MAC PDU) to be transmitted. For example, upon receiving an instruction from the MAC layer requesting the start of transmission, the PHY layer switches to transmit mode and can construct the information provided by the MAC layer (e.g., data) into a frame for transmission. Additionally, if the PHY layer detects a valid preamble of a received frame, it monitors the preamble header and sends an instruction to the MAC layer indicating the start of reception.

[0095] As such, information transmission and reception in wireless LAN systems are carried out in the form of frames, and for this purpose, the Physical Layer Protocol Data Unit (PPDU) format is defined.

[0096] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIGNAL) field, and a Data field. The most basic (e.g., the non-HT (High Throughput)) PPDU format illustrated in FIG. 7 may consist only of Legacy-STF (Legacy-STF), Legacy-LTF (Legacy-LTF), Legacy-SIG (Legacy-SIG) fields and a Data field. In addition, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or other types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF, (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the data field. More specific details will be described later with reference to FIG. 7.

[0097] STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, and precise time synchronization, while LTF is a signal for channel estimation and frequency error estimation. STF and LTF can be considered signals for synchronization and channel estimation in the OFDM physical layer.

[0098] The SIG field may contain various information related to the transmission and reception of the PPDU. 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 contain information regarding the modulation and coding rates of the data. For example, the 12-bit Length field may contain information regarding the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of the 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 a multiple of 3 + 2.

[0099] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), 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 receiver. The PSDU corresponds to a MAC PDU defined at the MAC layer and may contain data generated or used by the upper layer. The PPDU TAIL bits may be used to return the encoder to a 0 state. Padding bits may be used to adjust the length of the data field to a predetermined unit.

[0100] A 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 is composed of a MAC PDU and can be transmitted or received through the PSDU of the data portion in the PPDU format.

[0101] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may contain control information necessary for transmitting or receiving frames. The Duration / ID field may be set as the time for transmitting the corresponding frame. Address subfields may indicate the frame's receiver address, transmitter address, destination address, and source address, and some address subfields may be omitted. Specific details regarding each subfield of the MAC header, including Sequence Control, QoS Control, and HT Control subfields, can be found in the IEEE 802.11 standard document.

[0102] The Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP is a frame format that includes the PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and additionally, non-legacy SIG, non-legacy STF, and non-legacy LTF if present) from a standard PPDU format, but excludes the remaining parts (i.e., the data field).

[0103] FIG. 7 is a drawing illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure may be applied.

[0104] Various forms of PPDU have been used in standards such as IEEE 802.11a / g / n / ac / ax. 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 the non-HT PPDU format (Fig. 7(a)).

[0105] The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format illustrated in FIG. 7(b) may be referred to as the HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field, without including L-STF, L-LTF, and L-SIG (not shown).

[0106] An example of the VHT PPDU format (IEEE 802.11ac) includes the VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).

[0107] An example of the HE PPDU format (IEEE 802.11ax) includes the RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in addition to the basic PPDU format (Fig. 7(d)). Depending on the specific examples of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multiple users (MU), but is not included in the HE PPDU format for single users (SU). Additionally, the HE trigger-based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field may vary to 8 µs. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16 µs. For example, RL-SIG can be configured identically to L-SIG. Based on the presence of RL-SIG, the receiving STA can determine that the received PPDU is a HE PPDU or the EHT PPDU described later.

[0108] The EHT PPDU format may include the EHT MU (multi-user) of FIG. 7(e) and the EHT TB (trigger-based) PPDU of FIG. 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes RL-SIG following L-SIG, but it may include U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following RL-SIG.

[0109] The EHT MU PPDU of FIG. 7(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.

[0110] The EHT-SIG is omitted in the EHT TB PPDU of FIG. 7(f) compared to the EHT MU PPDU. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0111] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated so that demodulation and decoding can be attempted even on legacy STAs, and mapped based on a defined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated so that they can be demodulated and decoded by a STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) to obtain the information contained in the corresponding fields, and mapped based on a defined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0112] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulation fields. Also, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as pre-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0113] The U-SIG included in the EHT PPDU format of FIG. 7 can be constructed based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol for the U-SIG (e.g., OFDM symbol) can have a duration of 4 µs, and the U-SIG can have a total duration of 8 µs. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0114] U-SIGs can be configured in 20 MHz units. For example, if an 80 MHz PPDU is configured, the same U-SIG can be duplicated in 20 MHz units. That is, four identical U-SIGs can be included within an 80 MHz PPDU. If the bandwidth exceeds 80 MHz, for example, for a 160 MHz PPDU, the U-SIG of the first 80 MHz unit and the U-SIG of the second 80 MHz unit may be different.

[0115] For example, A number of uncoded bits may be transmitted through U-SIG, and the first symbol of U-SIG (e.g., U-SIG-1 symbol) transmits the first X bits of the total A bit information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) transmits the remaining Y bits of the total A bit information. The A bit information (e.g., 52 uncoded bits) may include a CRC field (e.g., a field of 4 bits) and a tail field (e.g., a field of 6 bits). The tail field may be used to terminate the trellis of the convolution decoder and may be set to, for example, 0.

[0116] A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG may be included in a new PPDU format not shown in FIG. 7 (e.g., UHR PPDU format), and 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.

[0117] For example, the size of the version-independent bits of U-SIG can be fixed or variable. The version-independent bits may be assigned only to U-SIG-1 symbols or to both U-SIG-1 and U-SIG-2 symbols. The version-independent bits and version-dependent bits may be referred to by various names, such as the first control bit and the second control bit.

[0118] For example, the version-independent bits of 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 U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value of the UL / DL flag field relates to DL communication. The version-independent bits of U-SIG may include information regarding the length of the TXOP (transmission opportunity) and information regarding the BSS color ID.

[0119] For example, the version-dependent bits of U-SIG may contain information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0120] Information necessary for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information regarding bandwidth, information regarding MCS techniques applied to non-legacy SIGs (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether DCM (dual carrier modulation) techniques (e.g., techniques to achieve an effect similar to frequency diversity by reusing the same signal on two subcarriers) are applied to non-legacy SIGs, information regarding the number of symbols used for non-legacy SIGs, and information regarding whether non-legacy SIGs are generated across the entire band.

[0121] Some of the information required for PPDU transmission and reception may be included in U-SIG and / or non-legacy SIGs (e.g., EHT-SIG or UHR-SIG, etc.). For example, information regarding the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information regarding the length of non-legacy LTF and cyclic prefix (CP) length, information regarding guard interval (GI) applied to non-legacy LTF, information regarding preamble puncturing applicable to PPDU, information regarding resource unit (RU) allocation, etc., may be included only in U-SIG, may be included only in non-legacy SIG, or may be indicated by a combination of information included in U-SIG and information included in non-legacy SIG.

[0122] Preamble puncturing may refer to the transmission of a PPDU in which a signal is not present in one or more frequency units within the PPDU bandwidth. For example, the size of the frequency unit (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 larger.

[0123] In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. A non-legacy SIG may be transmitted through at least one symbol, and one symbol may have a length of 4 µs. Information regarding the number of symbols used for EHT-SIG may be included in the previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0124] Non-legacy SIGs, such as HE-SIG-B and EHT-SIG, may include common fields and user-specific fields. Common fields and user-specific fields may be coded individually.

[0125] In some cases, the common field may be omitted. For example, in a compression mode where non-OFDMA (orthogonal frequency multiple access) is applied, the common field may be omitted, and multiple STAs may receive PPDUs (e.g., the data field of the PPDU) over the same frequency band. In a non-compression mode where OFDMA is applied, multiple users may receive PPDUs (e.g., the data field of the PPDU) over different frequency bands.

[0126] The number of user-specific fields can be determined based on the number of users. A single user block field can contain up to two user fields. Each user field may be related to MU-MIMO allocation or non-MU-MIMO allocation.

[0127] The common field may include CRC bits and Tail bits, the length of the CRC bits may be determined to be 4 bits, and the length of the Tail bits may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information regarding the location of the RU to which a plurality of users (i.e., a plurality of receiving STAs) are allocated.

[0128] An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on the OFDMA technique. Additionally, an RU may be defined when transmitting signals to a single STA. Resources may be allocated on an RU basis for non-legacy STF, non-legacy LTF, and Data fields.

[0129] Applicable RU sizes can be defined according to the PPDU bandwidth. RUs may be defined identically or differently for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU placement for HE PPDU and EHT PPDU may differ. The applicable RU sizes, number of RUs, RU locations, DC (direct current) subcarrier locations and numbers, null subcarrier locations and numbers, and guard subcarrier locations and numbers for each PPDU bandwidth can be referred to as a tone-plan. For example, a tone-plan for a wide bandwidth may be defined as a multiple repetition of a tone-plan for a low bandwidth.

[0130] RUs of various sizes can be defined as 26-ton RUs, 52-ton RUs, 106-ton RUs, 242-ton RUs, 484-ton RUs, 996-ton RUs, 2x996-ton RUs, 3x996-ton RUs, etc. An MRU (multiple RU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers composed of multiple RUs. For example, one MRU can be defined as 52+26-tons, 106+26-tons, 484+242-tons, 996+484-tons, 996+484+242-tons, 2x996+484-tons, 3x996-tons, or 3x996+484-tons. In addition, multiple RUs constituting a single MRU may be continuous or non-continuous in the frequency domain.

[0131] The specific size of the RU may be reduced or expanded. Accordingly, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not limited and is exemplary. Additionally, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) in this disclosure, the number of RUs may vary depending on the RU size.

[0132] The names of the respective fields in the PPDU formats of FIG. 7 are exemplary and the scope of the present disclosure is not limited by such names. Furthermore, the examples of the present disclosure may be applied not only to the PPDU formats exemplified in FIG. 7, but also to new PPDU formats based on the PPDU formats of FIG. 7 in which some fields are excluded and / or some fields are added.

[0133] Trigger frame

[0134] FIG. 8 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0135] A trigger frame may allocate resources for one or more TB PPDU transmissions and request TB PPDU transmissions. The trigger frame may also include other information required by an STA that transmits a TB PPDU in response. The trigger frame may include common info and user info list fields in the frame body.

[0136] The common information field may include information that is commonly applied to one or more TB PPDU transmissions requested by the trigger frame, for example, trigger type, UL length, whether there is a subsequent trigger frame (e.g., More TF), whether there is a CS (channel sensing) request, UL BW (bandwidth), etc.

[0137] The user information list contains zero or more user info fields. Figure 8 illustrates an exemplary EHT variant user info field format.

[0138] The AID12 subfield basically indicates that it is a user information field for the STA with the corresponding AID. Additionally, if the AID12 field has a specific predetermined value, it may be utilized for other purposes, such as assigning a Random Access (RA)-RU or being configured as a special user info field. A special user info field is a user information field that does not contain user-specific information but includes extended common information not provided in the common information field. For example, a special user info field can be identified by an AID12 value of 2007, and a special user info field flag subfield within the common information field can indicate whether the special user info field is included.

[0139] The RU allocation subfield can indicate the size and location of the RU / MRU. To this end, the RU allocation subfield may be interpreted together with the PS160 (primary / secondary 160MHz) subfield of the user information field, the UL BW subfield of the common information field, etc. For example, as shown in Table 1 below, the mapping of B7-B1 of the RU allocation subfield can be defined together with the settings of B0 of the RU allocation subfield and the PS160 subfield. Table 1 shows an example of the encoding of the PS160 subfield and the RU allocation subfield of the EHT variant user information field.

[0140]

[0141]

[0142]

[0143]

[0144]

[0145] If B0 of the RU allocation subfield is set to 0, it indicates that the RU / MRU allocation is applied to the primary 80MHz channel, and if the value is set to 1, it indicates that the RU allocation is applied to the secondary 80MHz channel of the primary 160MHz. If B0 of the RU allocation subfield is set to 0, it indicates that the RU / MRU allocation is applied to the lower 80MHz of the secondary 160MHz, and if the value is set to 1, it indicates that the RU allocation is applied to the upper 80MHz of the secondary 160MHz.

[0146] In the trigger frame RU allocation table of Table 1, the parameter N can be calculated based on the formula N=2*X1+X0. For bandwidths of 80 MHz or less, the values ​​of PS160, B0, X0, and X1 can be set to 0. For 160 MHz and 320 MHz bandwidths, the values ​​of PS160, B0, X0, and X1 can be set as shown in Table 2. These settings represent the absolute frequency order for the primary and secondary 80 MHz and 160 MHz channels. The order from left to right indicates the order from lowest to highest frequency. The primary 80 MHz channel is designated as P80, the secondary 80 MHz channel as S80, and the secondary 160 MHz channel as S160.

[0147]

[0148] FIG. 9 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0149] Figure 9 illustrates an exemplary format of the EHT variant common info field in the trigger frame exemplified in Figure 8.

[0150] The trigger type subfield identifies the variant of the trigger frame.

[0151] The uplink length (UL(uplink) length) subfield indicates the value of the L-SIG LENGTH field of the solicited TB PPDU.

[0152] The more TF(trigger frame) subfield indicates whether the transmission of a subsequent trigger frame is scheduled.

[0153] The Carrier Sense Required (CS) subfield is set to 1 to indicate that the STAs identified in the User Info field use energy detection (ED) to sense the medium and must consider the medium state and network allocation vector (NAV) when determining whether to respond. The CS Required subfield is set to 0 to indicate that the STAs identified in the User Info field do not need to consider the medium state or NAV when determining whether to respond.

[0154] The uplink bandwidth (UL BW (bandwidth)) subfield, together with the uplink bandwidth extension (UL BW extension) subfield of the special user info field, indicates the bandwidth within the U-SIG field of the EHT TB PPDU.

[0155] If the trigger type subfield indicates a MU-RTS (request to send) trigger frame as the type of the corresponding trigger frame, B20-B1 of the EHT variant common info field corresponds to the trigger TXOP (transmission opportunity) sharing mode subfield. Otherwise, B20-B1 of the EHT variant common info field corresponds to the GI (guard interval) and HE / ETF-LTF type subfields. The GI and HE / ETF-LTF type subfield indicates the GI and HE / EHT-LTF types of the HE or EHT TB PPDU response. The trigger TXOP sharing mode subfield indicates the triggered TXOP mode.

[0156] B22 of the EHT variant common info field is reserved and set to 0.

[0157] The number of HE / EHT symbols subfield indicates the number of HE-LTF symbols present in the HE TB PPDU or the number of EHT-LTF symbols present in the EHT TB PPDU.

[0158] B26 of the EHT variant common info field is reserved and set to 0.

[0159] The LDPC (low-density parity check) extra symbol segment subfield indicates the status of the LDPC extra symbol segment. If the LDPC extra symbol segment exists in the requested HE or EHT TB PPDU, it is set to 1, otherwise it is set to 0.

[0160] The AP transmission power (AP Tx(transmit) power) subfield indicates the combined transmission power of the AP at the transmission antenna connector of all antennas used to transmit the triggering PPDU in units of dBm / 20MHz.

[0161] The pre-FEC (forward error correction) padding factor subfield and the PE disambiguity subfield are encoded identically to the corresponding subfields in HE-SIG-A or EHT-SIG.

[0162] The UL spatial reuse subfield includes the spatial reuse n subfield (1 ≤ n ≤ 4). When a trigger frame requests an EHT TB PPDU, each spatial reuse n subfield of the EHT variant common info field is determined based on the EHT spatial reuse 1 subfield or the EHT spatial reuse 2 subfield of the special user info field.

[0163] B53 of the EHT variant common info field is reserved and set to 0.

[0164] The HE / EHT P160 subfield is set to 0 to indicate that the TB PPDU requested at the primary 160 MHz is an EHT TB PPDU. The HE / EHT P160 subfield is set to 1 to indicate that the TB PPDU requested at the primary 160 MHz is an HE TB PPDU.

[0165] The special user info field flag subfield is always set to 0 in the EHT variant common info field and indicates that the special user info field is included in the trigger frame containing the EHT variant common info field.

[0166] The trigger dependent common info subfield exists optionally based on the value of the trigger type field.

[0167] distributed tones RU (DRU)

[0168] Due to regulations in various regions, limitations on power spectral density (PSD) may be applied in the sub-7GHz (e.g., 6GHz) band. For a non-AP STA in the low-power indoor (LPI) band, the PSD limit may be -1dBm / MHz. For example, for a standard 52-tone RU, the maximum transmit (Tx) power may be approximately 6dBm.

[0169] In addition, different restrictions may apply to the 2.4GHz and 5GHz bands. For example, in the EU, China, Japan, and Korea, a PSD limit of 10dBm / MHz may apply to the 2.4GHz band. For an existing 52-tone RU, this means the maximum Tx power could be approximately 17dBm. If the PSD limit can be bypassed in the 5GHz band, the transmit power can be increased. For example, for an existing 52-tone RU, the maximum transmit power is 24dBm, which is still 6dBm below the maximum allowable EIRP (effective isotropic radiated power) of 30dBm.

[0170] If PSD limitations are overcome, transmit power can be increased, thereby improving spectrum efficiency or extending the range.

[0171] Considering that the PSD limit is defined per MHz for each STA, when tones of small-sized RUs are distributed over a wide bandwidth, the tones for each STA are non-contiguous, so each tone can be transmitted at high power. A RU containing such distributed tones is called a distributed RU (DRU), and to distinguish it from this, a RU containing continuous tones defined in existing wireless LAN systems (e.g., systems conforming to IEEE 802.11ax, 11be, etc.) can be called a regular RU (RRU).

[0172] Compared to a conventional STA transmitting an RRU, a STA transmitting a DRU can use higher power. For example, a 52-tone DRU spanning 80 MHz has only one tone per MHz, whereas a 52-tone RRU has approximately 13 tones per MHz. Assuming a PSD limit of -1 dBm / MHz in the 6 GHz LPI band, using a DRU can increase transmit power by 11 dB compared to a 52-tone RU. Increasing transmit power in this way allows for the application of a higher MCS and enables support over longer ranges.

[0173] FIG. 10 is a drawing illustrating an example of a distributed-tone RU in a wireless LAN system to which the present disclosure may be applied.

[0174] The example in FIG. 10 illustrates a case where STA1 transmits on DRU1, STA2 transmits on DRU2, and STA3 transmits on DRU3. Each STA can have a transmit power boost applied by using a DRU. Compared to using an RRU of the same size, higher transmit power is applied to all tones in the DRU, and thus spectral efficiency can be significantly improved. As such, the DRU can be particularly useful in UL-OFDMA.

[0175] DRUs can also be utilized in the case of APs. In some cases, APs can perform DL-OFDMA transmission to STA(s) using only some of DRU1, DRU2, and DRU3, in which case a transmit power boost due to the use of DRUs may be applied.

[0176] To maximize power boost, tones within a single DRU can be dispersed as far apart as possible. For example, a DRU containing one tone per MHz can be considered an optimal example. The size of the DRU (or the number of available tones included in a single DRU, i.e., the number of remaining tones excluding unusable tones such as null tones, guard tones, and DC tones) can be defined as equal to the size of the RRU (or the number of available tones included in a single RRU). Accordingly, the impact on various technologies previously defined based on RRUs can be minimized.

[0177] Table 3 shows examples of achievable power boosts (in dB) for various DRUs distributed across different bandwidths.

[0178] 20MHz Bandwidth 40MHz Bandwidth 80MHz Bandwidth 26-ton RU8.1311.1411.1452-ton RU6.378.1311.14106-ton RU3.366.378.13242-ton RU Not Applied 2.695.12484-ton RU Not Applied Not Applied 2.69

[0179] The examples in Table 3 assume a 6 GHz LPI band, and power boosts can also be obtained in the 2.4 GHz and 5 GHz bands in other regions. For example, in an 80 MHz UL-OFDMA transmission by 8 users, when each user uses a 106-ton DRU, the overall performance can be improved by approximately 8.13 dB compared to when each user uses a 106-ton RRU. In this way, by using DRUs, PSD limitations can be overcome and significant gains can be obtained.

[0180] How to set guard interval (GI) and LTF type subfields in a trigger frame

[0181] In order to overcome PSD constraints in a wireless LAN system (802.11) and obtain better power gain, a distributed tones RU (DRU) that uses distributed tones instead of continuous tones can be defined.

[0182] Various DRU operation modes for UHR TB PPDU transmission are discussed as follows.

[0183] - DRU tones are distributed across the entire PPDU bandwidth of 20 / 40 / 80 MHz.

[0184] - In the case of an unpunctured 80MHz PPDU, the DRU can be transmitted with a distributed frequency bandwidth (DBW) of 20MHz+20MHz+40MHz or 40MHz+20MHz+20MHz or 80MHz.

[0185] - Hybrid modes of DRU and RRU can be supported on different 80MHz subblocks within the broadband of 160MHz and 320MHz.

[0186] Puncturing mode operation of DRUs distributed over 20 MHz and 40 MHz in an 80 MHz bandwidth or 80 MHz frequency subblock (i.e., unallocated mode operation where some frequency bandwidth is not allocated for DRU transmission) may be supported.

[0187] FIG. 11 is a drawing illustrating a DRU operation mode according to one embodiment of the present disclosure.

[0188] Various DRU operation modes may be supported as shown in FIG. 11, and DRU signaling needs to be performed flexibly to enable the use of these DRU operation modes. FIG. 11 is an example of DRU operation modes, but the present disclosure is not limited thereto.

[0189] In Fig. 11(a), DRU transmission in an 80MHz PPDU is exemplified.

[0190] Figure 11(b) illustrates DRU transmission in an unpunctured 80MHz PPDU with a 20MHz+20MHz+40MHz DBW set.

[0191] FIG. 11(c) illustrates DRU transmission in a punctured 80 MHz PPDU. FIG. 11(c) illustrates a punctured 20 MHz (i.e., 20 MHz is unallocated for DRU transmission), and the location and size of the punctured bandwidth may be set differently.

[0192] Figure 11(d) illustrates a hybrid mode of 80 MHz DRU transmission and 80 MHz RRU transmission in a 160 MHz PPDU.

[0193] Figure 11(e) illustrates DRU transmission per 80 MHz in a 160 MHz PPDU. The left 80 MHz (subblock) in Figure 11(e) illustrates a case where the leftmost 20 MHz and the rightmost 40 MHz are set as DBW, and the middle 20 MHz illustrates a punctured (i.e., unallocated) frequency bandwidth.

[0194] To enable different DRU operation modes as described above, the following information may be indicated within the UHR trigger frame.

[0195] - Information on RU types: DRU or RRU

[0196] - Information on DRU Distributed Bandwidth (DBW): For example, 20MHz / 40MHz / 80MHz when DRU is transmitted

[0197] - Information on DRU allocation: DRU index / size (e.g., 26-ton DRU, 52-ton DRU, 106-ton DRU, 242-ton DRU, 484-ton DRU)

[0198] For DRU allocation instructions, existing entries in the 802.11be RU Allocation subfield table can be reused for DRU allocation.

[0199] For example, a DRU tone plan can have a hierarchical structure similar to an RRU. Additionally, a DRU tone plan can be a subset of an RRU, and a DRU tone plan can have the same number of DRUs as an RRU of the same size. That is, a single RU allocation subfield table can be used for both DRUs and RRUs.

[0200] RU types per 80 MHz may be specified. In this case, hybrid transmission of DRU and RRU within an 80 MHz frequency subblock may not be allowed.

[0201] When DRU transmission is authorized for UL TB PPDU, the DRU distributed bandwidth (DBW) may be specified in the corresponding user information field. A distributed bandwidth (DBW) of 20 MHz, 40 MHz, or 80 MHz may be specified in the user information field for DRU transmission.

[0202] FIG. 12 illustrates a trigger frame for DRU signaling according to one embodiment of the present disclosure.

[0203] Referring to Fig. 12, DRU signaling can be transmitted in the UHR trigger frame.

[0204] - RU Type Indication:

[0205] A 4-bit bitmap within the Common Info Field / Special User Info Field may be used for DRU indication. 1 bit may be used to indicate each 80 MHz used for DRU or RRU.

[0206] - DRU Distributed Bandwidth (DBW) Indicator:

[0207] When the DRU is transmitted, 2 bits of the SS (spatial stream) Allocation subfield within the User Info Field can be reused for distributed bandwidth indication.

[0208] The number of spatial streams may be limited to a maximum of 2 streams. Other informational indications within user information fields, such as modulation and coding scheme (MCS), coding, and target received power, may be maintained identically to RRU signaling.

[0209] FIG. 13 illustrates DRU signaling according to one embodiment of the present disclosure.

[0210] In Figure 13, it is assumed that the bandwidth of the UHR TB PPDU is 320 MHz and that it supports a hybrid mode of DRU and RRU in different 80 MHz frequency subblocks.

[0211] FIG. 13 illustrates the following operations per 80 MHz sub-block. It illustrates DRU transmission in the first punctured 80 MHz sub-block, DRU transmission in the second unpunctured 80 MHz sub-block, RRU transmission in the third 80 MHz sub-block, and DRU transmission in the fourth unpunctured 80 MHz sub-block.

[0212] In this case, a 4-bit bitmap of the common information field (or special user information field) may be used to indicate the RU type. For example, each bit of the bitmap may correspond to each 80 MHz sub-block, and a value of 0 may indicate DRU, and a value of 1 may indicate RRU.

[0213] Additionally, the DRU distributed BW (DBW) indication may utilize 2 bits of the SS allocation subfield. For example, a value of '00' may indicate DBW 20 MHz, a value of '01' may indicate DBW 40 MHz, and a value of '10' may indicate DBW 80 MHz. Additionally, a value of '11' may indicate DBW 60 MHz, and DBW 60 MHz may be supported when the highest frequency of 20 MHz in the 80 MHz frequency subblock is unallocated (or punctured). In the example of FIG. 13, for the first 80 MHz subblock, '00' (20 MHz) may be indicated in the user information field for a specific user, and '01' (40 MHz) may be indicated in the user information field for a specific user. Additionally, for the second 80 MHz subblock, '10' (80 MHz) may be indicated in the user information field for a specific user. In addition, for the 4th 80MHz sub-block, '10' (80MHz) can be indicated in the user information field for a specific user.

[0214] For DRU-based transmission in the aforementioned TB PPDU, the trigger frame (or control frame such as RTS, CTS, etc.) may include information related to DRU transmission.

[0215] For example, information related to DRU transmission may include information indicating whether DRU is applied or RRU is applied. Such information may be defined as a 1-bit size or as a bitmap having a length corresponding to a predetermined channel size. One bit of the bitmap may correspond to an 80 MHz channel, and the bit value at each bit position may indicate whether DRU is applied or RRU is applied to the corresponding 80 MHz channel.

[0216] A predetermined channel size corresponding to the bitmap length may correspond to the maximum channel size to which the DRU is applicable. If the bandwidth of the TB PPDU is greater than the predetermined channel size, multiple bitmaps may be included in the trigger frame (or control frames such as RTS, CTS, etc.). Accordingly, the maximum channel size to which the DRU is applicable may be identified (or implicitly indicated) based on the bitmap length and / or number. Alternatively, information regarding the predetermined channel size (or the maximum channel size to which the DRU is applicable) may be explicitly included in the trigger frame (or control frames such as RTS, CTS, etc.).

[0217] Additionally, the trigger frame may include information indicating the channel size to which the DRU is applied, and the DRU allocation information, whether the DRU is applied, the channel size information, and the DRU allocation information can be provided through specific values ​​of the trigger frame's fields or through combinations of each value.

[0218] The present disclosure proposes a method for setting / defining a guard interval (GI) and an LTF type (e.g., HE-LTF type or UHR-LTF type) subfield in a trigger frame that triggers a TB PPDU transmitting a PPDU using a DRU.

[0219] FIG. 14 is a diagram showing an exemplary format of a trigger frame in a wireless LAN system to which the present disclosure may be applied.

[0220] Figure 14 illustrates the UHR variant common info field of a trigger frame defined in 802.11bn (UHR). Below, only the parts that differ from the EHT variant common info field of Figure 9 will be explained.

[0221] Referring to FIG. 14, if the trigger type subfield (B0-B3) indicates a MU-RTS trigger frame, B20-B21 of the HE, EHT, or UHR variant common information field corresponds to the TXS (triggered TXOP sharing) mode subfield. Otherwise, B20-B21 of the HE variant common information field corresponds to the GI and HE-LTF type subfields, B20-B21 of the EHT variant common information field corresponds to the GI and HE / EHT-LTF type subfields, and B20-B21 of the UHR variant common information field corresponds to the GI and HE / UHR-LTF type subfields. The GI and HE-LTF type subfields, GI and HE / EHT-LTF type subfields, or GI and HE / UHR-LTF type subfields of the common information field indicate the GI and HE / EHT / UHR-LTF types of the HE, EHT, or UHR TB PPDU response. The GI and HE-LTF type subfields or the GI and HE / EHT-LTF type subfields exist within the trigger frame requesting (soliciting) the TB PPDU response.

[0222] GI and HE / UHR-LTF type subfields exist within the trigger frame soliciting a TB PPDU response, and the encoding of the GI and HE / UHR-LTF type subfields is defined in Table 4. If the GI and HE / UHR-LTF type subfields are set to 3 within an individually addressed (affressed) BSRP (buffer status report poll) trigger frame, the PPDU transmitted in response to the BSRP trigger frame corresponds to a non-HT (duplicated) PPDU containing a multi-STA BlockAck frame. If the GI and HE / UHR-LTF type subfields are set to a value other than 3 in the BSRP trigger frame, the PPDU transmitted in response to the BSRP trigger frame uses the TB PPDU format.

[0223] Description of GI and UHR-LTF Type Subfield Values 01× HE / UHR-LTF + 1.6 μs GI1 2× HE / UHR-LTF + 1.6 μs GI2 4× HE / UHR-LTF + 3.2 μs GI3 The response PPDU format is a non-HT (duplicate) PPDU format including Multi-STA BlockAck.

[0224] The DRU / RRU indication subfield indicates whether a distributed RU (DRU) or regular RU (RRU) transmission is requested in each 80 MHz frequency subblock. The format of the DRU / RRU indication subfield is as shown in FIG. 15. FIG. 15 illustrates the format of the DRU / RRU indication subfield in a wireless LAN system to which the present disclosure may be applied. If the UL BW (uplink bandwidth) is 20 MHz, 40 MHz, or 80 MHz, B1-B3 in the DRU / RRU indication subfield are reserved. If the UL BW (uplink bandwidth) is 160 MHz, B2-B3 in the DRU / RRU indication subfield are reserved. To solicit a UHR TB PPDU utilizing DRU transmission in an 80 MHz frequency subblock, the corresponding bits in the DRU / RRU indication subfield are set to 0. Otherwise, the corresponding bit is set to 1.

[0225] The intermediate frame check sequence (IFCS) present flag subfield and the UHR reserved subfield are as follows.

[0226] The IFCS presence flag subfield of the UHR variant common information field indicates whether an IFCS exists. If this subfield is set to 0, it indicates that an IFCS exists. Conversely, if this subfield is set to 1, it indicates that an IFCS does not exist.

[0227] B61-B62 of the UHR variant common information fields are UHR reserved and are all set to 1.

[0228] The present disclosure proposes a method for designing, configuring, and defining GI and HE / UHR-LTF type subfields in a trigger frame that triggers a TB PPDU of DRU transmission. In addition, the aforementioned existing GI and HE / UHR-LTF type subfields can be used in a trigger frame that triggers a TB PPDU in which only RRU is used.

[0229] 1) First, consider the case where only DRU is used in the TB PPDU (i.e., RRU is not used in the TB PPDU, and the DRU / RRU instruction subfield indicates that there is no instruction to use RRU in the TB PPDU and that DRU is used).

[0230] This case may correspond, for example, when B0 of the DRU / RRU instruction subfield is set to 0 during a 20 / 40 / 80 MHz TB PPDU trigger. Or, as another example, when both B0 and B1 of the DRU / RRU instruction subfield are set to 0 during a 160 MHz TB PPDU trigger. Or, as yet another example, when all bits of the DRU / RRU instruction subfield are set to 0 during a 320 MHz TB PPDU trigger.

[0231] Since a single GI and HE / UHR-LTF type subfield indicates both the LTF type and the GI type, different STAs assigned to different DRUs will use the same type of LTF and GI when transmitting TB PPDU.

[0232] In the above situation, to reduce the overhead of the TB PPDU, GI and HE / UHR-LTF type subfields can be defined as follows. Since this situation involves the use of DRU and is therefore necessarily UHR-LTF, HE is not shown in the table below for the sake of convenience of explanation.

[0233] GI and UHR-LTF Type Subfield Value Description 0 Reserved 1 Reserved 2 4× UHR-LTF + 0.8 μs GI or 4× UHR-LTF + 1.6 μs GI or 4× UHR-LTF + 3.2 μs GI 3 The response PPDU format is a non-HT (duplicate) PPDU format including Multi-STA BlockAck or is reserved

[0234] Referring to Table 5, when triggering a TB PPDU in which only DRU is used in the trigger frame, the corresponding GI and UHR-LTF type subfields can always be set to 2, which indicates the existing 4× UHR-LTF. Additionally, the value 2 can indicate 0.8 μs GI, 1.6 μs GI, or 3.2 μs GI. In other words, one of the three GI values ​​can be defined as a description of the value 2 in the GI and UHR-LTF type subfields. In this case, when triggering a TB PPDU in which only DRU is used in the trigger frame, the GI and UHR-LTF type subfields are set to the value 2, and this value can indicate one of the defined GI values ​​among i) 4× UHR-LTF and ii) 0.8 μs GI, 1.6 μs GI, or 3.2 μs GI.

[0235] Additionally or alternatively, the GI and UHR-LTF type subfields themselves may be reserved. In this case, they may be implicitly indicated as 4× UHR-LTF + 0.8 μs GI, 4× UHR-LTF + 1.6 μs GI, or 4× UHR-LTF + 3.2 μs GI. As with the previous example, they may be predefined as one of the three GI values. That is, when triggering a TB PPDU in which only DRU is used in the trigger frame, they may always be indicated as a specific type among the three types: 4× UHR-LTF + 0.8 μs GI, 4× UHR-LTF + 1.6 μs GI, or 4× UHR-LTF + 3.2 μs GI.

[0236] Additionally or alternatively, as shown in Table 6 below, the existing descriptions for each value excluding the value of 2 are maintained, but when triggering a TB PPDU in which only DRU is used in the trigger frame, the GI and UHR-LTF type subfields can always be set to a value of 2.

[0237] Description of GI and UHR-LTF Type Subfield Values 01× UHR-LTF + 1.6 μs GI 12× UHR-LTF + 1.6 μs GI 24× UHR-LTF + 0.8 μs GI or 4× UHR-LTF + 1.6 μs GI or 4× UHR-LTF + 3.2 μs GI 3 The response PPDU format is a non-HT (duplicate) PPDU format containing Multi-STA BlockAck.

[0238] Referring to Table 6, when triggering a TB PPDU in which only DRU is used in the trigger frame, the corresponding GI and UHR-LTF type subfields can always be set to 2, which indicates the existing 4× UHR-LTF. Additionally, the value 2 can indicate 0.8 μs GI, 1.6 μs GI, or 3.2 μs GI. In other words, one of the three GI values ​​can be defined as a description of the value 2 in the GI and UHR-LTF type subfields. In this case, when triggering a TB PPDU in which only DRU is used in the trigger frame, the GI and UHR-LTF type subfields are set to the value 2, and this value can indicate one of the defined GI values ​​among i) 4× UHR-LTF and ii) 0.8 μs GI, 1.6 μs GI, or 3.2 μs GI.

[0239] Additionally or alternatively, as shown in Table 7 below, one can consider a situation where all values ​​except for 3 basically indicate 4× UHR-LTF. Here, a value of 0 in the GI and UHR-LTF type subfields may indicate a specific type or be reserved.

[0240] Description of GI and UHR-LTF Type Subfield Values 0 4× UHR-LTF + 0.8 μs GI or 4× UHR-LTF + 1.6 μs GI or Reserved 1 4× UHR-LTF + 1.6 μs GI 2 4× UHR-LTF + 3.2 μs GI 3 The response PPDU format is a non-HT (duplicate) PPDU format including Multi-STA BlockAck or is reserved

[0241] Referring to Table 7, any one of 4× UHR-LTF + 0.8 μs GI, 4× UHR-LTF + 1.6 μs GI, or Reserved may be defined as the description for the 0 value of the GI and UHR-LTF type subfields. In this case, when triggering a TB PPDU in which only DRU is used in the trigger frame, the GI and UHR-LTF type subfields may indicate any one of the values ​​0, 1, or 2, and the GI and UHR-LTF types corresponding to the indicated value may be used for TB PPDU transmission.

[0242] In this case, the UHR-LTF type is fixed at 4× UHR-LTF, but since one of several types of GI can be specified, there is an advantage in that GI can be set flexibly.

[0243] Additionally, or alternatively, as shown in Table 8 below, the existing descriptions of each value of the GI and UHR-LTF type subfields are maintained, but when triggering a TB PPDU in which only DRU is used in the trigger frame, the GI and UHR-LTF type subfields can always be set to a value of 2.

[0244] Description of GI and UHR-LTF Type Subfield Values 01× UHR-LTF + 1.6 μs GI 12× UHR-LTF + 1.6 μs GI 24× UHR-LTF + 3.2 μs GI 3 The response PPDU format is a non-HT (duplicate) PPDU format including Multi-STA BlockAck.

[0245] Referring to Table 8, the definitions of the GI and UHR-LTF type subfields within the trigger frame are the same as the existing ones (see Table 4), but when triggering a TB PPDU in which only DRU is used in the trigger frame, the GI and UHR-LTF type subfields can always be set to a value of 2.

[0246] 2) Next, consider the case where hybrid mode is used in the TB PPDU (i.e., RRU and DRU are used simultaneously in the TB PPDU, and the DRU / RRU indication subfield indicates the simultaneous use of RRU and DRU for the TB PPDU).

[0247] In this case, for example, it may correspond to a situation where, when triggering a 160 MHz TB PPDU, either B0 or ​​B1 of the DRU / RRU instruction subfield is set to 0 and the other to 1. Alternatively, as another example, it may correspond to a situation where, when triggering a 320 MHz TB PPDU, some of the bits of the DRU / RRU instruction subfield are set to 0 and the rest to 1. Additionally, the situation of triggering a 20 / 40 / 80 MHz TB PPDU may not correspond to a situation where hybrid mode is used.

[0248] Since a single GI and HE / UHR-LTF type subfield indicates both the LTF type and the GI type, different STAs assigned to different DRUs and RRUs will use the same type of LTF and GI when transmitting TB PPDU. However, in RRU and DRU transmissions, even if the LTF type is the same, the LTF sequence may be different.

[0249] The definitions of the GI and HE / UHR-LTF type subfields in the trigger frame that triggers a TB PPDU in which hybrid mode is used may be the same as the definitions of the GI and HE / UHR-LTF type subfields in the trigger frame in the case where only DRU is used in the TB PPDU described above, and the indication method may also be the same.

[0250] Additionally, or alternatively, when triggering a TB PPDU in hybrid mode, the GI and HE / UHR-LTF type subfields can be defined as shown in Table 9 below.

[0251] GI and HE / UHR-LTF Type Subfield Value Description 0 Reserved 1 Reserved 2 4× HE / UHR-LTF + 3.2 μs GI 3 The response PPDU format is a non-HT (duplicate) PPDU format including Multi-STA BlockAck or reserved

[0252] Referring to Table 9, when triggering a TB PPDU in hybrid mode in the trigger frame, the values ​​of the GI and HE / UHR-LTF type subfields can always be set to 2, so that only 4× HE / UHR-LTF + 3.2 μs GI instructions are valid. In this case, it may be desirable because only 4× HE / UHR-LTF + 3.2 μs GI is valid in the RRU.

[0253] Additionally, or alternatively, as shown in Table 10 below, the existing descriptions for each value excluding the value of 2 are maintained, but when triggering a TB PPDU in hybrid mode in the trigger frame, the GI and HE / UHR-LTF type subfields can always be set to only the value of 2.

[0254] Description of GI and HE / UHR-LTF Type Subfield Values 01× HE / UHR-LTF + 1.6 μs GI1 2× HE / UHR-LTF + 1.6 μs GI2 4× HE / UHR-LTF + 3.2 μs GI3 The response PPDU format is a non-HT (duplicate) PPDU format including Multi-STA BlockAck.

[0255] Referring to Table 10, the definitions of the GI and HE / UHR-LTF type subfields within the trigger frame are the same as the existing ones (see Table 4), but when triggering a TB PPDU in which hybrid mode is used in the trigger frame, the GI and HE / UHR-LTF type subfields can always be set to a value of 2.

[0256] According to an embodiment of the present disclosure, unlike conventional GI and HE / UHR-LTF type subfields, an indication of only a specific LTF type (e.g., 4× HE / UHR-LTF) may be defined within the GI and HE / UHR-LTF type subfields. Additionally, according to an embodiment of the present disclosure, an indication of the 4× LTF type may be indicated by specific values ​​only when triggering a TB PPDU in which only DRU is used in the trigger frame. Additionally, according to an embodiment of the present disclosure, a specific GI indication may be applied only when triggering a TB PPDU in which only DRU is used in the trigger frame. Additionally, according to an embodiment of the present disclosure, when triggering a TB PPDU in which a hybrid mode is used, the values ​​of the GI and HE / UHR-LTF type subfields may always be defined as 2 (i.e., always apply 4× LTF + 3.2 μs GI).

[0257] FIG. 16 is a drawing illustrating a PPDU format according to one embodiment of the present disclosure.

[0258] Referring to FIG. 16, a UHR PPDU that can be used in a UHR system may include some format features of HE TB PPDU and EHT TB PPDU. For example, a UHR PPDU (e.g., UHR TB PPDU) may be configured to include L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-STF, UHR-LTF(s), and data fields.

[0259] In addition, although not shown in FIG. 16, the UHR PPDU (e.g., UHR MU PPDU) may be configured to include an additional UHR SIG between the U-SIG and UHR-STF.

[0260] In FIG. 16, L-STF, L-LTF, and L-SIG may be referred to as legacy parts, RL-SIG, U-SIG, and UHR-SIG (if included) may be referred to as SIG parts, UHR-STF may be referred to as STF parts, and UHR-LTF may be referred to as LTF parts.

[0261] All or part of all parts (i.e., fields) of FIG. 16 may be divided into multiple subparts / subfields. Each field (and its subfields) may be transmitted in units of 4us * N (where N is an integer). Additionally, it may include a Guard Interval (GI) (or short GI) as defined in conventional wireless LAN systems. A common subcarrier frequency spacing value (delta_f = 312.5 kHz / N or 312.5 kHz * N, where N is an integer) may be applied to all of the illustrated fields, or a first delta_f may be applied to the first part (e.g., all of the legacy part, all / part of the SIG part), and a second delta_f (e.g., a value smaller than the first delta_f) may be applied to all / part of the remaining parts.

[0262] Some of the illustrated fields may be omitted, and the order of the fields is illustrated illustratively and may be changed in various ways.

[0263] The SIG part may include various control information for the transmitted PPDU. For example, it may include an STF part, an LTF part, and control information for decoding the data. For example, it may include all or part of the information included in the previously described HE-SIG-A information, information included in the HE-SIG-B information, information included in the U-SIG information, and information included in the EHT-SIG.

[0264] The STF part may include an STF sequence.

[0265] The LTF part may include a training field (i.e., an LTF sequence) for channel estimation.

[0266] The data field contains user data and may include packets for the upper layer. That is, it may include MPDU (MAC Frame).

[0267] FIG. 17 illustrates the operation of an STA device for a PPDU transmission and reception method according to one embodiment of the present disclosure.

[0268] FIG. 17 illustrates the operation of an STA device based on the previously proposed methods. The example in FIG. 17 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 17 may be omitted depending on the situation and / or setting.

[0269] Referring to FIG. 17, the STA device receives a trigger frame from the AP device (S1701).

[0270] Here, the trigger frame can trigger / instruct the transmission of the STA's PPDU (i.e., TB PPDU transmission).

[0271] Here, the trigger frame may include a common information field and a user information field. For example, the trigger frame may include a UHR variant common information field and a UHR variant user information field.

[0272] The common information field may include a DRU / RRU instruction field indicating whether a distributed-tone resource unit (DRU) transmission or a regular resource unit (RRU) transmission is requested for each frequency subblock of the PPDU. Here, each bit of the 4-bit DRU / RRU instruction subfield may indicate DRU transmission or RRU transmission for each 80 MHz frequency subblock of the PPDU. In other words, each bit of the 4 bits within the common information field may individually indicate whether a DRU transmission is requested for the lowest frequency 80 MHz frequency subblock, the second lowest frequency 80 MHz frequency subblock, the second highest frequency 80 MHz frequency subblock, and the highest frequency 80 MHz frequency subblock of the PPDU.

[0273] In addition, the common information field may include GI and LTF type subfields (e.g., GI and HE / UHR-LTF type subfields) indicating the guard interval (GI) and long training field (LTF) (e.g., HE / UHR-LTF) types of the PPDU.

[0274] Here, based on the indication of the DRU / RRU indication field, the GI and LTF (e.g., HE / UHR-LTF) types indicated by the values ​​of the GI and LTF type fields may be defined. In other words, the GI and LTF (e.g., HE / UHR-LTF) types for the PPDU indicated by the values ​​of the GI and LTF type subfields may be defined differently based on whether only one or more DRUs are included in the PPDU or whether one or more DRUs and one or more RRUs are included in the PPDU (i.e., based on the bit value of the DRU / RRU indication subfield, i) whether only DRU transmission is requested for the subblocks or ii) whether DRU transmission is requested for some subblocks and RRU transmission is requested for other subblocks).

[0275] For example, based on the fact that only DRU transmission within the PPDU is requested by the DRU / RRU indication field, the GI and LTF type fields can always be set to only 2 values. Accordingly, the GI and LTF types for the PPDU can be determined as the GI and LTF (e.g., UHR-LTF) types indicated by the 2 values ​​of the GI and LTF type fields.

[0276] In this case, the 0 and 1 values ​​of the GI and LTF type fields are reserved, and the 2 value of the GI and LTF type fields may indicate i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields may always be set to only the 2 value.

[0277] Additionally, a value of 0 in the GI and LTF type fields indicates 1× LTF + 1.6 μs GI, a value of 1 in the GI and LTF type fields indicates 2× LTF + 1.6 μs GI, and a value of 2 in the GI and LTF type fields may indicate i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields may always be set to only a value of 2.

[0278] Additionally, a value of 0 in the GI and LTF type fields indicates 1× LTF + 1.6 μs GI, a value of 1 in the GI and LTF type fields indicates 2× LTF + 1.6 μs GI, and a value of 2 in the GI and LTF type fields indicates 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields can always be set to only a value of 2.

[0279] As another example, based on the fact that only DRU transmission within the PPDU is requested by the DRU / RRU indication field, the GI and LTF type fields are reserved, and the GI and LTF type may be implicitly determined as i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) 4× LTF + 3.2 μs GI.

[0280] As another example, based on the fact that only DRU transmission within the PPDU is requested by the DRU / RRU indication field, a value of 0 of the GI and LTF type fields may indicate i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) reserved, a value of 1 of the GI and LTF type fields may indicate 4× LTF and 1.6 μs GI, and a value of 2 of the GI and LTF type fields may indicate 4× LTF and 3.2 μs GI. In this case, the GI and LTF types may be determined according to the values ​​of the GI and LTF type fields.

[0281] Additionally, for example, the GI and LTF type fields can always be set to only 2 values ​​based on the request for DRU transmission and RRU transmission within the PPDU by the DRU / RRU indication field. Accordingly, the GI and LTF types for the PPDU can be determined as the GI and LTF (e.g., HE / UHR-LTF) types indicated by the 2 values ​​of the GI and LTF type fields.

[0282] In this case, the 0 and 1 values ​​of the GI and LTF type fields are reserved, and the 2 value of the GI and LTF type fields may indicate 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields can always be set to only the 2 value.

[0283] Additionally, a value of 0 in the GI and LTF type fields indicates 1× LTF + 1.6 μs GI, a value of 1 in the GI and LTF type fields indicates 2× LTF + 1.6 μs GI, and a value of 2 in the GI and LTF type fields indicates 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields can always be set to only a value of 2.

[0284] The STA device transmits a PPDU to the AP device based on a trigger frame (S1702).

[0285] The STA device can obtain information regarding the Tone Plan, the type of LTF used, and information regarding the DRU. As described above, the information regarding the Tone Plan may include the size and location of the DRU / RRU, control information related to the DRU / RRU, information regarding the frequency band in which the DRU / RRU is included, and information regarding the STA transmitting and receiving the DRU / RRU. In particular, the pilot location of the DRU is already defined by the information regarding the size, location, and frequency band of the DRU, and this may be part of the pilot location used by the RRU, or it may be set separately from the pilot location of the RRU. Additionally, it may include information regarding the LTF applied to the corresponding PPDU and the GI of the LTF.

[0286] Additionally, the STA device can configure / generate a PPDU based on the acquired control information. The step of configuring / generating the PPDU may include the step of configuring / generating each field of the PPDU. That is, step S1702 includes the step of configuring U-SIG and UHR-SIG fields (e.g., UHR-SIG-A / B fields) containing control information regarding the Tone Plan. For example, step S1702 may include the step of configuring a field containing control information indicating the bandwidth of the PPDU and / or the step of configuring a field containing control information indicating the size / location of the DRU / RRU (e.g., N bitmap) and / or the step of configuring a field containing the identifier of the STA receiving the DRU / RRU (e.g., AID). In the case of a TB PPDU, only some of the information may be included.

[0287] Additionally, step S1702 may include the step of generating an STF / LTF sequence transmitted through a specific DRU. The STF / LTF sequence may be generated based on a pre-configured STF generation sequence / LTF generation sequence. In particular, the LTF may be a 4x LTF.

[0288] Additionally, step S1702 may include a step of generating a data field (i.e., MPDU) transmitted through a specific DRU.

[0289] For the S1702 operation, at least one of the following operations may be performed: cyclic shift diversity (CSD), spatial mapping, inverse discrete fourier transform (IDFT) / inverse fast fourier transform (IFFT) operation, guard interval (GI) insertion.

[0290] According to an embodiment of the present disclosure, throughput can be improved by reducing GI overhead in PPDU transmissions including DRUs. By setting an LTF type that is more suitable for PPDU transmissions including DRUs, channel state can be estimated more accurately, and frequency and timing synchronization performance can be improved.

[0291] A signal / field / sequence configured according to the present disclosure can be transmitted in the form of FIG. 16.

[0292] The method described in the example of FIG. 17 can be performed by the first device (200) of FIG. 1. For example, one or more processors (202) of the first device (200) of FIG. 1 may be configured to generate a PPDU and transmit the PPDU through transceiver(s) (106). Furthermore, one or more memories (204) of the first device (200) may store instructions for performing the method described in the example of FIG. 17 or the examples described above when executed by one or more processors (202).

[0293] FIG. 18 illustrates the operation of an AP device for a PPDU transmission and reception method according to one embodiment of the present disclosure.

[0294] FIG. 18 illustrates the operation of an AP device based on the previously proposed methods. The example in FIG. 18 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 18 may be omitted depending on the situation and / or configuration.

[0295] Referring to FIG. 18, the AP device transmits a trigger frame to the STA device (S1801).

[0296] Here, the trigger frame can trigger / instruct the transmission of the STA's PPDU (i.e., TB PPDU transmission).

[0297] Here, the trigger frame may include a common information field and a user information field. For example, the trigger frame may include a UHR variant common information field and a UHR variant user information field.

[0298] The common information field may include a DRU / RRU instruction field indicating whether a distributed-tone resource unit (DRU) transmission or a regular resource unit (RRU) transmission is requested for each frequency subblock of the PPDU. Here, each bit of the 4-bit DRU / RRU instruction subfield may indicate DRU transmission or RRU transmission for each 80 MHz frequency subblock of the PPDU. In other words, each bit of the 4 bits within the common information field may individually indicate whether a DRU transmission is requested for the lowest frequency 80 MHz frequency subblock, the second lowest frequency 80 MHz frequency subblock, the second highest frequency 80 MHz frequency subblock, and the highest frequency 80 MHz frequency subblock of the PPDU.

[0299] In addition, the common information field may include GI and LTF type subfields (e.g., GI and HE / UHR-LTF type subfields) indicating the guard interval (GI) and long training field (LTF) (e.g., HE / UHR-LTF) types of the PPDU.

[0300] Here, based on the indication of the DRU / RRU indication field, the GI and LTF (e.g., HE / UHR-LTF) types indicated by the values ​​of the GI and LTF type fields may be defined. In other words, the GI and LTF (e.g., HE / UHR-LTF) types for the PPDU indicated by the values ​​of the GI and LTF type subfields may be defined differently based on whether only one or more DRUs are included in the PPDU or whether one or more DRUs and one or more RRUs are included in the PPDU (i.e., based on the bit value of the DRU / RRU indication subfield, i) whether only DRU transmission is requested for the subblocks or ii) whether DRU transmission is requested for some subblocks and RRU transmission is requested for other subblocks).

[0301] For example, based on the fact that only DRU transmission within the PPDU is requested by the DRU / RRU indication field, the GI and LTF type fields can always be set to only 2 values. Accordingly, the GI and LTF types for the PPDU can be determined as the GI and LTF (e.g., UHR-LTF) types indicated by the 2 values ​​of the GI and LTF type fields.

[0302] In this case, the 0 and 1 values ​​of the GI and LTF type fields are reserved, and the 2 value of the GI and LTF type fields may indicate i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields may always be set to only the 2 value.

[0303] Additionally, a value of 0 in the GI and LTF type fields indicates 1× LTF + 1.6 μs GI, a value of 1 in the GI and LTF type fields indicates 2× LTF + 1.6 μs GI, and a value of 2 in the GI and LTF type fields may indicate i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields may always be set to only a value of 2.

[0304] Additionally, a value of 0 in the GI and LTF type fields indicates 1× LTF + 1.6 μs GI, a value of 1 in the GI and LTF type fields indicates 2× LTF + 1.6 μs GI, and a value of 2 in the GI and LTF type fields indicates 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields can always be set to only a value of 2.

[0305] As another example, based on the fact that only DRU transmission within the PPDU is requested by the DRU / RRU indication field, the GI and LTF type fields are reserved, and the GI and LTF type may be implicitly determined as i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) 4× LTF + 3.2 μs GI.

[0306] As another example, based on the fact that only DRU transmission within the PPDU is requested by the DRU / RRU indication field, a value of 0 of the GI and LTF type fields may indicate i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) reserved, a value of 1 of the GI and LTF type fields may indicate 4× LTF and 1.6 μs GI, and a value of 2 of the GI and LTF type fields may indicate 4× LTF and 3.2 μs GI. In this case, the GI and LTF types may be determined according to the values ​​of the GI and LTF type fields.

[0307] Additionally, for example, the GI and LTF type fields can always be set to only 2 values ​​based on the request for DRU transmission and RRU transmission within the PPDU by the DRU / RRU indication field. Accordingly, the GI and LTF types for the PPDU can be determined as the GI and LTF (e.g., HE / UHR-LTF) types indicated by the 2 values ​​of the GI and LTF type fields.

[0308] In this case, the 0 and 1 values ​​of the GI and LTF type fields are reserved, and the 2 value of the GI and LTF type fields may indicate 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields can always be set to only the 2 value.

[0309] Additionally, a value of 0 in the GI and LTF type fields indicates 1× LTF + 1.6 μs GI, a value of 1 in the GI and LTF type fields indicates 2× LTF + 1.6 μs GI, and a value of 2 in the GI and LTF type fields indicates 4× LTF + 3.2 μs GI. Here, the GI and LTF type fields can always be set to only a value of 2.

[0310] The AP device receives a PPDU from the STA device based on a trigger frame (S1802).

[0311] The AP device may receive all or part of the PPDU through step S1802. Here, for the operation of step S1802, the AP device may perform an operation to restore the results of CSD, Spatial Mapping, IDFT / IFFT operations, and GI insert operations applied by the STA device (e.g., applied in step S1702 above).

[0312] Here, the AP device can perform decoding of all or part of the PPDU. Additionally, the AP device can obtain control information related to the Tone Plan (i.e., DRU / RRU) from the decoded PPDU.

[0313] More specifically, the AP device can decode the L-SIG and U-SIG fields of the PPDU based on the legacy STF / LTF and obtain information contained in the L-SIG and U-SIG fields. For example, information regarding various Tone Plans (i.e., DRU / RRU) proposed in this disclosure may be included in the UHR-SIG field (e.g., UHR-SIG-A / B, etc.), and the AP device can obtain information regarding the Tone Plan (i.e., DRU / RRU) through the UHR-SIG field. In particular, the pilot location of the DRU is already defined by information regarding the size, location, and frequency band of the DRU, which may be part of the pilot locations used by the RRU or may be set separately from the pilot location of the RRU. When receiving a TB PPDU, the receiving AP may already know information regarding the Tone Plan (i.e., DRU / RRU).

[0314] In addition, the AP device can decode the remaining part of the PPDU based on information regarding the acquired Tone Plan (i.e., DRU / RRU). For example, the AP device can decode the STF / LTF fields of the PPDU based on information regarding the tone plan (i.e., DRU / RRU). Furthermore, the AP device can decode the data fields of the PPDU based on information regarding the Tone Plan (i.e., DRU / RRU) and acquire the MPDU contained in the data fields. Additionally, during decoding, the residual CFO can be corrected by performing CFO (carrier frequency offset) tracking based on the pilot positions acquired based on information regarding the Tone Plan (i.e., DRU / RRU).

[0315] Additionally, the AP device can perform a processing operation to transmit the decoded data to an upper layer (e.g., the MAC layer). Furthermore, if the generation of a signal is instructed from the upper layer to the PHY layer in response to the data transmitted to the upper layer, a subsequent operation can be performed.

[0316] According to an embodiment of the present disclosure, throughput can be improved by reducing GI overhead in PPDU transmissions including DRUs. By setting an LTF type that is more suitable for PPDU transmissions including DRUs, channel state can be estimated more accurately, and frequency and timing synchronization performance can be improved.

[0317] The method described in the example of FIG. 18 can be performed by the second device (200) of FIG. 1. For example, one or more processors (202) of the second device (200) of FIG. 1 may be configured to receive a PPDU through transceiver(s) (106) and process the PPDU. Furthermore, one or more memories (204) of the second device (200) may store instructions for performing the method described in the example of FIG. 18 or the examples described above when executed by one or more processors (202).

[0318] In conventional wireless LAN systems, the RU (i.e., RRU) allocated to each STA for OFDMA transmission consists only of continuous subcarriers in the frequency domain; however, in contrast, for OFDMA transmission according to the examples of the present disclosure, a RU (i.e., DRU) composed of discontinuous subcarriers may be allocated. Accordingly, by allocating a RU composed of discontinuous subcarriers, the transmission power can be improved, thereby achieving the effect of increasing wireless communication efficiency. In addition, throughput can be improved by reducing GI overhead in PPDU transmissions including a DRU. By setting an LTF type that is more suitable for PPDU transmissions including a DRU, channel state can be estimated more accurately, and frequency and timing synchronization performance can be improved.

[0319] The embodiments described above are combinations of the components and features of the present disclosure in a specific form. Each component or feature should be considered optional unless otherwise explicitly stated. Each component or feature may be implemented in a form not combined with other components or features. Additionally, it is possible to construct embodiments of the present disclosure by combining some components and / or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components or features of another embodiment. It is obvious that embodiments may be constructed by combining claims that are not explicitly related in the claims, or that they may be included as new claims by amendment after filing.

[0320] It is obvious to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential features of the present disclosure. Accordingly, the detailed description set forth above should not be interpreted restrictively in all respects and should be considered exemplary. The scope of the present disclosure shall be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0321] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that enable operations according to the methods of various embodiments to be executed on a device or computer, and a non-transitory computer-readable medium on which such software or instructions, etc. are stored and executable on a device or computer. Instructions that may be used to program a processing system to perform the features described in the present disclosure may be stored on or within a storage medium or a computer-readable storage medium, and the features described in the present disclosure may be implemented using a computer program product comprising such a storage medium. The storage medium may include, but is not limited to, high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, and may include non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory may optionally include one or more storage devices located remotely from the processor(s). Memory or alternatively, non-volatile memory device(s) within memory comprises a non-transient computer-readable storage medium. The features described in this disclosure may be stored in any one of the machine-readable media and integrated into software and / or firmware that can control the hardware of a processing system and allow the processing system to interact with other mechanisms utilizing results according to the embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0322] Although the method proposed in this disclosure has been described with an example applied to an IEEE 802.11-based system, it can be applied to various wireless LANs or wireless communication systems in addition to IEEE 802.11-based systems.

Claims

1. A method performed by a station (STA) in a wireless LAN system, wherein the method is: A step of receiving a trigger frame from an access point (AP); and It includes the step of transmitting a PPDU (physical protocol data unit) to the AP based on the above trigger frame, The trigger frame includes a DRU / RRU indication field indicating whether transmission of a distributed-tone resource unit (DRU) or a regular resource unit (RRU) is requested for the PPDU by frequency subblock, and GI and LTF type fields indicating the guard interval (GI) and long training field (LTF) types of the PPDU. A method in which the GI and LTF types indicated by the values ​​of the GI and LTF type fields are defined based on the indication of the DRU / RRU indication field.

2. In Paragraph 1, A method in which, based on the fact that only DRU transmission within the PPDU is requested by the DRU / RRU instruction field, the GI and LTF type fields are always set to a value of 2.

3. In Paragraph 2, The 0 and 1 values ​​of the above GI and LTF type fields are reserved, and A method in which the two values ​​of the GI and LTF type fields indicate i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) 4× LTF + 3.2 μs GI.

4. In Paragraph 2, A value of 0 in the above GI and LTF type fields indicates 1× LTF + 1.6 μs GI, and A value of 1 in the above GI and LTF type fields indicates 2× LTF + 1.6 μs GI, and A method in which the two values ​​of the GI and LTF type fields indicate i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) 4× LTF + 3.2 μs GI.

5. In Paragraph 2, A value of 0 in the above GI and LTF type fields indicates 1× LTF + 1.6 μs GI, and A value of 1 in the above GI and LTF type fields indicates 2× LTF + 1.6 μs GI, and A method in which the two values ​​of the GI and LTF type fields indicate 4× LTF + 3.2 μs GI.

6. In Paragraph 1, Based on the fact that only DRU transmission within the PPDU is requested by the DRU / RRU indication field, the GI and LTF type fields are reserved, and A method in which the GI and LTF types of the above PPDU are implicitly determined as i) 4× LTF and 0.8 μs GI, ii) 4× LTF and 1.6 μs GI, or iii) 4× LTF + 3.2 μs GI.

7. In Paragraph 1, Based on the fact that only DRU transmission within the PPDU is requested by the DRU / RRU indication field above, A value of 0 in the above GI and LTF type fields indicates i) 4× LTF and 0.8 μs GI, or ii) 4× LTF and 1.6 μs GI, or iii) is reserved, and A value of 1 in the above GI and LTF type fields indicates 4× LTF and 1.6 μs GI, and A method in which the two values ​​of the GI and LTF type fields indicate 4× LTF and 3.2 μs GI.

8. In Paragraph 1, A method in which, based on the request for DRU transmission and RRU transmission within the PPDU by the DRU / RRU instruction field, the GI and LTF type fields are always set to only 2 values.

9. In Paragraph 8, The 0 and 1 values ​​of the above GI and LTF type fields are reserved, and A method in which the two values ​​of the GI and LTF type fields indicate 4× LTF + 3.2 μs GI.

10. In Paragraph 8, A value of 0 in the above GI and LTF type fields indicates 1× LTF + 1.6 μs GI, and A value of 1 in the above GI and LTF type fields indicates 2× LTF + 1.6 μs GI, and A method in which the two values ​​of the GI and LTF type fields indicate 4× LTF + 3.2 μs GI.

11. In a station (STA) device in a wireless LAN system, the device comprises: One or more transceivers; and It includes one or more processors connected to the above one or more transmitters and receivers, and The above one or more processors are: Receive a trigger frame from an access point (AP); and It is configured to transmit a PPDU (physical protocol data unit) to the AP based on the above trigger frame, and The trigger frame includes a DRU / RRU indication field indicating whether transmission of a distributed-tone resource unit (DRU) or a regular resource unit (RRU) is requested for the PPDU by frequency subblock, and GI and LTF type fields indicating the guard interval (GI) and long training field (LTF) types of the PPDU. A device in which the GI and LTF types indicated by the values ​​of the GI and LTF type fields are defined based on the indication of the DRU / RRU indication field.

12. A method performed by an access point (AP) in a wireless LAN system, wherein the method comprises: A step of transmitting a trigger frame to a station (STA); and It includes the step of receiving a PPDU (physical protocol data unit) from the STA based on the above trigger frame, and The trigger frame includes a DRU / RRU indication field indicating whether transmission of a distributed-tone resource unit (DRU) or a regular resource unit (RRU) is requested for the PPDU by frequency subblock, and GI and LTF type fields indicating the guard interval (GI) and long training field (LTF) types of the PPDU. A method in which the GI and LTF types indicated by the values ​​of the GI and LTF type fields are defined based on the indication of the DRU / RRU indication field.

13. In an access point (AP) device in a wireless LAN system, the device comprises: One or more transceivers; and It includes one or more processors connected to the above one or more transmitters and receivers, and The above one or more processors are: Send a trigger frame to the station (STA); and It is configured to receive a PPDU (physical protocol data unit) from the STA based on the above trigger frame, and The trigger frame includes a DRU / RRU indication field indicating whether transmission of a distributed-tone resource unit (DRU) or a regular resource unit (RRU) is requested for the PPDU by frequency subblock, and GI and LTF type fields indicating the guard interval (GI) and long training field (LTF) types of the PPDU. A device in which the GI and LTF types indicated by the values ​​of the GI and LTF type fields are defined based on the indication of the DRU / RRU indication field.

14. In a processing device configured to control a station (STA) in a wireless LAN system, the processing device comprises: One or more processors; and A processing device comprising one or more computer memories that are operably connected to one or more processors and store instructions for performing a method according to any one of claims 1 to 10 based on execution by one or more processors.

15. One or more non-transitory computer-readable media storing one or more instructions, A computer-readable medium in which one or more of the above commands are executed by one or more processors to control a device in a wireless LAN system to perform a method according to any one of claims 1 to 10.

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