Method and apparatus for performing millimeter wave band-based PPDU transmission and reception in wireless LAN system

Abstract

Disclosed are a method and an apparatus for performing millimeter wave band-based PPDU transmission and reception in a wireless LAN system. A method, according to one embodiment of the present disclosure, may comprise the steps of: configuring a physical layer protocol data unit (PPDU) in a specific frequency band; and transmitting the PPDU to a second STA. Here, the PPDU may include at least one of a first short training field (STF) portion, a first long training field (LTF) portion, a first signal (SIG) portion, a second STF portion, a second LTF portion, a second SIG portion, or a data portion. The data portion may be configured on the basis of a resource unit (RU) size smaller than the smallest bandwidth supported in the specific frequency band.

Description

Method and apparatus for performing millimeter wave band-based PPDU transmission and reception in a wireless LAN system

[0001] The present disclosure relates to a method and apparatus for transmitting and receiving millimeter wave (mmWave) band-based PPDUs in a Wireless Local Area Network (WLAN) system.

[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 millimeter wave (mmWave) band-based PPDUs in a Wireless Local Area Network (WLAN) system.

[0005] In particular, the technical problem of the present disclosure is to provide a method and apparatus for transmitting and receiving PPDUs for an extended range in the millimeter wave (mmWave) band.

[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 first station (STA) in a wireless LAN system according to one aspect of the present disclosure may include: configuring a physical layer protocol data unit (PPDU) in a specific frequency band; and transmitting the PPDU to a second STA. Herein, the PPDU may include at least one of a first short training field (STF) portion, a first long training field (LTF) portion, a first signal (SIG) portion, a second STF portion, a second LTF portion, a second SIG portion, or a data portion. The data portion may be configured based on a resource unit (RU) size smaller than the smallest bandwidth supported in the specific frequency band.

[0008] A method performed by a second station (STA) in a wireless LAN system according to a further aspect of the present disclosure may include: receiving a physical layer protocol data unit (PPDU) in a specific frequency band; and processing the PPDU. Herein, the PPDU may include at least one of a first short training field (STF) portion, a first long training field (LTF) portion, a first signal (SIG) portion, a second STF portion, a second LTF portion, a second SIG portion, or a data portion. The data portion may be configured based on a resource unit (RU) size smaller than the smallest bandwidth supported in the specific frequency band.

[0009] According to the present disclosure, a method and apparatus for transmitting and receiving millimeter wave (mmWave) band-based PPDUs in a Wireless Local Area Network (WLAN) system may be provided.

[0010] According to the present disclosure, a method and apparatus for transmitting and receiving PPDU for an extended range in a millimeter wave (mmWave) band may be provided.

[0011] According to the present disclosure, there is an advantage in that the mmWave band can be efficiently supported in a wireless LAN system to achieve a high data rate and low latency.

[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 illustrates a sector level sweep (SLS) step that can be applied to the present disclosure.

[0022] FIG. 9 illustrates two types of sector sweeps that can be applied to the present disclosure.

[0023] FIG. 10 illustrates a BRP transaction that can be applied to the present disclosure.

[0024] FIG. 11 is a diagram showing regional examples of channeling in the millimeter wave (mmWave) band to which the present disclosure can be applied.

[0025] FIG. 12 shows an example of a basic PPDU format in the mmWave band according to an embodiment of the present disclosure.

[0026] FIG. 13 shows an example of a PPDU format for an extended range in the mmWave band according to an embodiment of the present disclosure.

[0027] FIG. 14 illustrates the operation of a first STA according to an embodiment of the present disclosure.

[0028] FIG. 15 illustrates the operation of a second STA according to an embodiment of the present disclosure.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The following describes the technical features to which the examples of the present disclosure may be applied.

[0036] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0037] 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), base station (BS), fixed station, Node B, base transceiver system (BTS), network, artificial intelligence (AI) system, road side unit (RSU), repeater, router, relay, gateway, etc.

[0038] 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.

[0039] 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.

[0040] 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).

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] FIG. 2 is a drawing showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0050] 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.

[0051] 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.

[0052] 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).

[0053] 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.

[0054] 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.

[0055] 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).

[0056] 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.

[0057] 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.

[0058] In addition to the structure of the aforementioned DS, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0059] 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.

[0060] 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.

[0061] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0062] 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.

[0063] 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.

[0064] 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).

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied.

[0075] 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.

[0076] 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).

[0077] Referring 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, ...).

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] FIG. 5 is a diagram illustrating a CSMA / CA-based frame transmission operation to which the present disclosure may be applied.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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).

[0100] FIG. 7 is a drawing illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure may be applied.

[0101] 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)).

[0102] 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).

[0103] 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)).

[0104] 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 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 microseconds (us). 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 16us. 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] For example, the size of the version-independent bits of U-SIG may 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.

[0115] 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.

[0116] 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.).

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.).

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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, 4x996-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.

[0128] 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.

[0129] 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.

[0130] Beamforming training

[0131] Beamforming training can determine appropriate receiving and transmitting antenna sectors for paired STAs. This can be achieved through the transmission of a bidirectional training frame sequence.

[0132] The beamforming phase is divided into two sub-phases. First, the initial coarse-grain antenna sector configuration can be determined during the sector level sweep (SLS). This information is used in the subsequent optional beam refinement phase (BRP), where fine-tuning of the selected sector can be performed.

[0133] First, the operation in the SLS phase is explained.

[0134] During SLS, the two STAs can each train either the transmitting antenna sector or the receiving antenna sector.

[0135] During SLS, a pair of stations can find the sector providing the highest signal quality by exchanging a series of sector sweep (SSW) frames (or beacons in the case of transmission sector training in PCP / AP) across multiple antenna sectors. For example, during SLS, each station can operate once as a transmitter and once as a receiver of the sweep, as shown in Fig. 8.

[0136] FIG. 8 illustrates a sector level sweep (SLS) step that can be applied to the present disclosure.

[0137] Referring to FIG. 8, the STA that performs the transmission first corresponds to the initiator, and the other STA in the pair may correspond to the responder.

[0138] The initiator's sweep and the responder's sweep can be utilized in two different ways, as shown in Fig. 9.

[0139] FIG. 9 illustrates two types of sector sweeps that can be applied to the present disclosure.

[0140] Referring to FIG. 9, FIG. 9 (a) represents a transmit sector sweep (TXSS), and FIG. 9 (b) represents a receive sector sweep (RXSS).

[0141] During a transmit sector sweep (TXSS), frames are transmitted from different sectors, while the pairing node can receive them in a quasi-omni-directional pattern. To identify the strongest transmission sector, the transmitter can mark identifiers for the antenna and sector used for all frames.

[0142] Additionally, during a receive sector sweep (RXSS), transmissions within the same sector (the best-known sector) can test the optimal receive sector at the pairing node. Overall, the following four types of sweep combinations for SLS are possible.

[0143] - Send sector sweep (TXSS) on both initiator and responder

[0144] - Receive Sector Sweep (RXSS) on both STAs

[0145] - Initiator RXSS and Respondent TXSS

[0146] - Initiator TXSS and responder RXSS

[0147] For the achieved optimal SNR and TXSS, sector and antenna identifiers can be reported to the pairing node, and such SLS feedback can follow the structure shown in FIG. 7.

[0148] Feedback to the initiator is conveyed via every frame of the responder sector sweep, which can guarantee reception under an optimal antenna configuration that is not yet known. Feedback to the responder can be transmitted as a single SSW feedback PPDU / frame at the determined optimal antenna configuration. Finally, the SSW feedback PPDU / frame can be acknowledged by the responder with an SSW-ACK. The final PPDU / frame can be additionally used to negotiate the details of the subsequent BRP.

[0149] If the two STAs have sufficient transmit antenna gain, their SLS phase can be realized as pure transmit sector training, and receive sector training can be deferred to a subsequent BRP. Additionally, the initiator can instruct / request the responder to perform a receive sector sweep by specifying the number of receive sectors to be trained during their sweep, i.e., the initiator's sweep. If the initiator sweep corresponds to receive sector training, an additional signal may be required prior to the SLS phase.

[0150] Next, the operation in BRP is explained.

[0151] BRP can refine sectors found in the SLS stage. These sectors are determined using a non-uniform quasi-omni-directional antenna pattern and may have suboptimal signal quality. Additionally, BRP can predict the optimization of antenna weight vectors regardless of pre-defined sector patterns for phased antenna arrays.

[0152] This allows for increasing the beam training search space while simultaneously obtaining additional throughput gains. Although free variation of the antenna weight vector can result in arbitrary antenna patterns, directional characteristics can be preserved for antenna configurations that provide high throughput. Therefore, the training process for optimizing pre-defined directional sectors and antenna weight vectors can remain the same. Finally, if BRP is not part of the previous SLS, BRP can be used to train the receiver antenna configuration.

[0153] A BRP transaction can evaluate a set of directional transmission or reception patterns against the directional configuration known to be the best at the pairing node. Thus, the imperfections of quasi-omnidirectional patterns can be prevented. Since BRP relies on the preceding SLS step, reliable PPDU / frame exchange is guaranteed, and various antenna configurations can be tested across the same PPDU / frame. This can significantly reduce transmission overhead, unlike SLS, which requires the entire PPDU / frame to test a sector. In this regard, to sweep antenna configurations across the entire PPDU / frame, transmit and receive training fields (TRN-T / R) can be added to the PPDU / frame exchanged during the BRP transaction. Each field can be transmitted or received with the antenna configuration to test signal quality. The remainder of the PPDU / frame can be transmitted and received with the antenna configuration known to be the best.

[0154] BRP receive antenna training can be requested by specifying the number of configurations to test in the L-RX header field of the PPDU / frame. The pairing node may add that number of TRN-R fields to the next PPDU / frame. Transmit training can be requested by setting the TX-TRN-REQ header field and adding the TRN-T field to the same BRP PPDU / frame. Optionally, an acknowledgment PPDU / frame with the TX-TRN-OK field set and no training fields added may be transmitted by the receiver before the requester adds the TRN-T field to the next PPDU / frame. As with SLS, BRP feedback may be provided in the form of the SNR for the best found configuration and, in the case of transmit training, the best configuration ID.

[0155] FIG. 10 illustrates a BRP transaction that can be applied to the present disclosure.

[0156] Referring to Fig. 10, the BRP transaction can be configured to first train the receiving configuration between two STAs and then perform additional sending training refinement.

[0157] For example, STA B can combine transmit and receive training requests into a single PPDU / frame using the aforementioned request variation. On the other hand, STA A can request two transmit directions using two PPDU / frames.

[0158] The BRP phase may follow immediately after SLS using an SSW ACK frame for parameter exchange. Alternatively, the BRP phase may be initiated based on a special BRP setup sub-phase consisting of a BRP frame without a training field. In either case, the L-RX and TX-TRN-REQ fields may be used to exchange BRP parameters.

[0159] Definition of PPDU format for extended range and transmission / reception method

[0160] In next-generation wireless LAN systems, mmWave bands including the 60 GHz band (i.e., not limited to the 60 GHz band) may be used to improve throughput and efficiency. In this case, sector-level sweep (SLS) is required for beamforming application, and a PPDU format for this needs to be defined.

[0161] Taking these points into consideration, the present disclosure proposes a specific method for defining a PPDU format for SLS in the mmWave band.

[0162] FIG. 11 is a diagram showing regional examples of channeling in the millimeter wave (mmWave) band to which the present disclosure can be applied.

[0163] The example in Fig. 11 shows the mmWave bands used in the United States, the European Union, South Korea, Japan, Australia, and China, and indicates the size and location of the channels defined in the bands. For example, the bandwidth of each of the six channels may correspond to 2.16 GHz. Additionally, when bandwidth bonding is applied, up to four unit bandwidths can be bonded to support a bandwidth of up to 8.64 GHz.

[0164] In existing wireless LAN systems, the bandwidths supported by wireless LAN systems corresponding to 1x numerology (e.g., IEEE 802.11ac (VHT) based systems) are 20, 40, 80, and 160 MHz. For bandwidths of 20, 40, 80, and 160 MHz, the number of subcarriers is defined as 64, 128, 256, and 512, respectively. Additionally, a tone plan is defined for the number and location of DC subcarriers, guard subcarriers, null subcarriers, pilot subcarriers, etc. Additionally, subcarrier spacing is defined as 312.5 kHz, OFDM symbol length excluding CP (cyclic prefix) length as 3.2 µs, and applicable guard intervals as 0.8 µs and 0.4 µs.

[0165] Additionally, the bandwidths supported by wireless LAN systems corresponding to 4x numerology (e.g., IEEE 802.11ax (HE) or IEEE 802.11be (EHT) based systems) are 20, 40, 80, 160, and 320 MHz. For the bandwidths of 20, 40, 80, 160, and 320 MHz, the number of subcarriers is defined as 256, 512, 1024, 2048, and 4096, respectively. Additionally, RU / MRU tone plans are defined for the number and location of DC subcarriers, guard subcarriers, null subcarriers, pilot subcarriers, etc. Additionally, subcarrier spacing is defined as 78.125 kHz, the OFDM symbol length excluding CP length is defined as 12.8 µs, and applicable guard intervals are defined as 3.2 µs, 1.6 µs, and 0.8 µs.

[0166] Unlike these existing wireless LAN systems, technologies under discussion such as UHR are discussing the use of sub-7GHz bands (e.g., 2.4GHz, 5GHz, or 6GHz bands) and / or mmWave bands to achieve high data rates and low latency. For example, for certain use cases requiring high throughput, it is difficult to satisfy the requirements with only the bandwidth of currently defined channels, so transmitting / receiving specific PPDUs through mmWave bands may be considered.

[0167] However, in the mmWavw band, the signal has strong linearity, so it is necessary to transmit a PPDU with beamforming applied, and for this, the application of sector level sweep (SLS) may be essential.

[0168] In the mmWave band, bandwidth and tone plan, etc., can be configured by applying upclocking to the aforementioned 1x numerology and / or 4x numerology. That is, a new numerology in the mmWave band can be defined based on an N-fold upclocking relationship with the existing 1x numerology or 4x numerology. Here, N can correspond to values ​​such as 4, 8, 10, etc.

[0169] Here, upclocking may refer to an operation in which the sampling time is accelerated by rapidly changing the clock speed, thereby increasing the bandwidth (BW). Here, the sampling time can be defined as 1 / BW. For example, N-fold upclocking may correspond to an operation in which the sampling time becomes N-fold faster (i.e., 1 / (N*BW)) by rapidly changing the clock speed N-fold, and the bandwidth is increased N-fold accordingly. Here, N may be referred to as the upclocking factor.

[0170] Specifically, when applying N-fold upclocking in the mmWave band, the bandwidth is the existing bandwidth * N, the number of subcarriers is the same as the number in the existing bandwidth, the subcarrier spacing is the existing subcarrier spacing * N, and the symbol duration can be the existing symbol duration / N.

[0171] For example, a new numerology based on existing 1x numerology (e.g., 1x numerology in IEEE 802.11ac) may be defined as follows: the bandwidth is one of 20*N, 40*N, 80*N, or 160*N MHz; the subcarrier spacing is 312.5*N kHz; the number of subcarriers is one of 64, 128, 256, or 512; and the OFDM symbol length excluding the guard interval (or CP length) may be defined as 3.2 / N us. Here, candidate values ​​for the guard interval may be defined as 0.8 / N and 0.4 / N us. Additionally, a 160*2N MHz bandwidth (i.e., 1024 subcarriers) with the 160*N MHz tone plan repeated twice or a 160*4N MHz bandwidth (i.e., 2048 subcarriers) with the 160*N MHz tone plan repeated four times may be defined.

[0172] For example, a new numerology based on existing 4x numerology (e.g., 4x numerology in IEEE 802.11ax / 11be) can be defined as follows: the bandwidth is one of 20*N, 40*N, 80*N, 160*N, or 320*N MHz; the subcarrier spacing is 78.125*N kHz; the number of subcarriers is one of 256, 512, 1024, 2048, or 4096; and the OFDM symbol length excluding the guard interval (or CP length) can be defined as 12.8 / N us. Here, candidate values ​​for the guard interval can be defined as 0.8 / N, 1.6 / N, and 3.2 / N us. Additionally, a 320*2N MHz bandwidth (i.e., 8192 subcarriers) can be defined by repeating a 320*N MHz tone plan twice.

[0173] Based on the aforementioned numerology and / or numerology reused in the mmWave band, a PPDU format for SLS in the mmWave band can be defined.

[0174] PPDUs transmitted in the mmWave band can be defined by a preamble and a data field. Here, regarding the preamble, an existing legacy preamble may or may not exist; if it does not exist, it may briefly have the structure of STF, LTF, SIG, and Data.

[0175] FIG. 12 shows an example of a basic PPDU format in the mmWave band according to an embodiment of the present disclosure.

[0176] Referring to Fig. 12, the basic PPDU format in the mmWave band can be configured to include UHR-STF, UHR-LTF, UHR-SIG, and / or data fields.

[0177] In this regard, UHR-STF, UHR-LTF, and UHR-SIG described in this disclosure are examples of names referring to STF, LTF, and SIG in next-generation wireless LAN systems, and may be replaced with other names that perform the same function.

[0178] In the case of the mmWave band, the impact of interference due to beamforming and line of sight (LoS) characteristics may be minimal. Therefore, it may not be necessary to define a PPDU format considering compatibility, interoperability, and / or coexistence with STAs in existing wireless LAN systems (e.g., STAs / terminals according to IEEE 802.11ad / ay standards).

[0179] With these points in mind, a PPDU format in the mmWave band (e.g., a PPDU format for SLS) can be defined as a simple structure of UHR-STF, UHR-LTF, UHR-SIG, and / or data fields as shown in FIG. 12.

[0180] Below, each field illustrated in FIG. 12 is described in detail, and a new PPDU format for an extended range based on the structure is defined.

[0181] Example 1

[0182] The present embodiment relates to a case where a PPDU format (e.g., a PPDU format for SLS) in the mmWave band is composed of UHR-STF, UHR-LTF, UHR-SIG, and a data field / part.

[0183] First, the UHR-STF structure within the corresponding PPDU format will be explained.

[0184] For example, the structure of UHR-STF can be defined by applying N-fold upclocking based on L-STF or VHT-STF defined in each bandwidth (bandwidth, BW) prior to upclocking application.

[0185] However, when based on VHT-STF, UHR-STF can be constructed by repeating VHT-STF twice to estimate the coarse CFO (carrier frequency offset). When based on L-STF, UHR-STF can be identical to the existing structure, and its length can be changed to 1 / N.

[0186] When based on VHT-STF, UHR-STF can ultimately have a length of 8 / N us by applying upclocking. In this regard, VHT-STF has a length of 4 us and a structure in which a 0.8 us signal is repeated 5 times. That is, UHR-STF can consequently have a structure in which a 0.8 / N us signal is repeated a total of 10 times. Alternatively, for robust performance, a number of repetitions other than 10 may be used, and a number of repetitions other than 10 may also be used when based on L-STF.

[0187] As another example, the structure of UHR-STF can be defined by applying N-fold upclocking to the HE-STF or EHT-STF defined in each bandwidth prior to upclocking application. In this case, for coarse CFO estimation, UHR-STF can be constructed by repeating HE-STF or EHT-STF twice. Here, 1x HE-STF or 1x EHT-STF has a length of 4 us and can have a structure in which a 0.8 us signal is repeated 5 times. Additionally, 2x HE-STF or 2x EHT-STF has a length of 8 us and can have a structure in which a 1.6 us signal is repeated 5 times.

[0188] Accordingly, when based on 1x HE-STF or 1x EHT-STF, the UHR-STF included in the PPDU format proposed in this embodiment may have a length of 8 / N us. Alternatively, when based on 2x HE-STF or 2x EHT-STF, the UHR-STF included in the PPDU format proposed in this embodiment may have a length of 16 / N us. That is, the UHR-STF may consequently have a structure in which a 0.8 / N us signal or a 1.6 / N us signal is repeated a total of 10 times. Alternatively, a different number of repetitions other than 10 may be used for robust performance.

[0189] In this regard, in terms of CFO estimation, it may be desirable for UHR-STF to be defined based on L-STF or VHT-STF or 1x HE-STF or 1x EHT-STF.

[0190] The various structures described above for UHR-STF can be extended and applied in the same way not only to PPDUs for SLS but also to UHR-STFs of other PPDU formats used in the mmWave band.

[0191] Next, the UHR-LTF structure within the corresponding PPDU format is explained.

[0192] For example, the structure of UHR-LTF can be defined by applying N-fold upclocking to the L-LTF or VHT-LTF defined in each bandwidth prior to upclocking application. However, in the case of being based on VHT-LTF, for fine CFO estimation, the GI (guard interval) within the VHT-LTF may be repeated twice (i.e., GI*2) and placed at the beginning, and the part of the VHT-LTF excluding the GI (i.e., LTS (long training symbol)) may be repeated twice and placed at the end, and N-fold upclocking may be applied to this. That is, UHR-LTF can have a structure of [GI*2 + LTS + LTS]. In the case of being based on L-LTF, UHR-LTF may be identical to the existing structure, and its length may be changed to 1 / N.

[0193] Here, the length of the GI of VHT-LTF is 0.8 us (or 0.4 us in the case of short GI), and the length of the part excluding GI, i.e., the LTS, is 3.2 us. Therefore, the length of GI*2 can be 1.6 / N (or 0.8 / N) us, and the length of the LTS can be 3.2 / N us.

[0194] As another example, the structure of UHR-LTF can be defined by applying N-fold upclocking to the HE-LTF or EHT-LTF defined in each bandwidth prior to upclocking application. However, for fine CFO estimation, the GI (guard interval) within the corresponding HE-LTF or EHT-LTF may be repeated twice (i.e., GI*2) and positioned at the beginning, and the part excluding the GI (i.e., LTS (long training symbol)) may be repeated twice and positioned at the end, and N-fold upclocking may be applied to this. That is, UHR-LTF can have a structure of [GI*2 + LTS + LTS].

[0195] Here, the length of GI in HE-LTF or EHT-LTF is 0.8 us, 1.6 us, or 3.2 us, and the length of the part excluding GI, i.e., LTS, is 3.2 us, 6.4 us, or 12.8 us in 1x / 2x / 4x HE-LTF or EHT-LTF, respectively. Therefore, the length of GI*2 can be 1.6 / N us, 3.2 / N us, or 6.4 / N us, and the length of LTS can be 3.2 / N us, 6.4 / N us, or 12.8 / N us.

[0196] In this regard, in terms of channel estimation, it may be preferable for UHR-LTF to be defined based on 4x HE-LTF or 4x EHT-LTF. Additionally or alternatively, in terms of CFO estimation, it may be preferable for UHR-LTF to be defined based on L-LTF or VHT-LTF or 1x HE-LTF or 1x EHT-LTF. Additionally or alternatively, considering the trade-off between the two aforementioned aspects, it may be preferable for UHR-LTF to be defined based on 2x HE-LTF or 2x EHT-LTF.

[0197] The various structures described above for UHR-LTF can be extended and applied in the same way not only to PPDUs for SLS but also to UHR-LTFs of other PPDU formats used in the mmWave band.

[0198] Next, the UHR-SIG structure within the corresponding PPDU format and the information included / transmitted will be explained.

[0199] For example, the structure of UHR-SIG can be constructed based on the aforementioned 1x numerology. In this case, one symbol may have a length of 3.2 / N us excluding GI. This may be suitable when UHR-LTF within the corresponding PPDU format is constructed based on L-LTF or VHT-LTF, and may be available in all options of UHR-LTF.

[0200] As another example, the structure of UHR-SIG can be constructed based on the aforementioned 4x numerology. In this case, one symbol may have a length of 12.8 / N us excluding GI. This may be suitable when the UHR-LTF within the corresponding PPDU format is constructed based on HE-LTF or EHT-LTF (e.g., 2x HE-LTF / EHT-LTF or 4x HE-LTF / EHT-LTF).

[0201] Additionally, UHR-SIG can be repeated identically in 20*N MHz increments. This may be suitable when UHR-LTF within the corresponding PPDU format is configured based on L-LTF and may be available in all options of UHR-LTF.

[0202] Alternatively, the UHR-SIG may be configured based on the entire bandwidth. For example, if based on 1x numerology prior to upclocking, the UHR-SIG may be configured with the same tone plan as the data field / part in each bandwidth of the VHT. As another example, if based on 4x numerology prior to upclocking, the UHR-SIG may be configured with the same tone plan as the data field / part in each bandwidth of the HE / EHT. This may be suitable for UHR-LTF options other than those configured based on L-LTF within the corresponding PPDU format, and allows for the transmission / delivery of more information. This is because, if based on L-LTF, channel estimation of tones located at the 20 MHz boundary may not be possible.

[0203] Additionally, UHR-SIG can be fixed to a specific number of symbols. For example, UHR-SIG in the PPDU format for SLS can be fixed to 2 symbols. This is just one example, and UHR-SIG can also be fixed to a different number of symbols.

[0204] Additionally, regarding UHR-SIG, the MCS and coding may be fixed. For example, regarding UHR-SIG within the corresponding PPDU format, the MCS and coding may be fixed to BCC BPSK 1 / 2. This is just one example, but it may also be fixed to other coding and MCS values.

[0205] The various structures described above for UHR-SIG can be extended and applied in the same way not only to PPDUs for SLS but also to UHR-SIGs of other PPDU formats used in the mmWave band.

[0206] The aforementioned UHR-SIG can be composed of various contents.

[0207] For example, through the UHR-SIG in the corresponding PPDU format, information such as the PHY version, bandwidth, UL / DL information, and MCS, coding, and spatial stream count (NSS) applied to the data field / part for decoding the data field / part may be transmitted / transmitted.

[0208] Additionally, UHR-SIG may also contain information regarding BSS color values. In this regard, assuming a case where transmission, i.e., SLS transmission, is initiated on a specific link in the sub-7 GHz band, the information regarding BSS color values ​​may be set to the BSS color value of the link initiating the transmission. Alternatively, an ID corresponding to the mmWave band link performing the transmission, i.e., SLS transmission, may be set as the information regarding BSS color values, or it may be set using a subfield different from the BSS color.

[0209] Additionally, the UHR-SIG may indicate that the PPDU containing the UHR-SIG corresponds to a specific PPDU format, namely, a PPDU format for SLS. This indication may be implicitly conveyed through a combination of other information included in the UHR-SIG or explicitly conveyed through a specific subfield. For example, the number of bits in the subfield for the PPDU format indication may be determined according to the PPDU format defined in the mmWave band. Specifically, the subfield may consist of 1 bit when two types of PPDU formats are defined, and 2 bits when three or four types of PPDU formats are defined.

[0210] The aforementioned various contents can be similarly included, extended, or applied not only to PPDUs for SLS but also to UHR-SIGs of other PPDU formats used in the mmWave band.

[0211] Next, the structure of the data fields / parts within the corresponding PPDU format and the information included / transmitted will be explained.

[0212] The structure of the data field / part can be configured as various structures proposed for the aforementioned UHR-SIG. For example, the data field / part can be configured based on the aforementioned 1x numerology or 4x numerology, and can be repeated in units of 20*N MHz or configured based on the entire bandwidth.

[0213] This structure can be extended and applied in the same way not only to PPDUs for SLS but also to data fields / parts of other PPDU formats used in the mmWave band.

[0214] Example 2

[0215] This embodiment relates to a method for defining a PPDU format for an extended range based on the structure of a basic PPDU format (e.g., the PPDU format described in Example 1).

[0216] The PPDU format for extended range can be defined / configured by considering various options such as the following.

[0217] 1) Power boosting

[0218] PPDUs for extended range can be transmitted with power boosted by a specific amount compared to basic PPDUs. For example, 3 dB boosting can be applied.

[0219] The power boosting can be applied to all fields of the PPDU, or to only some fields. For example, power boosting can be applied only to the STF / LTF within the PPDU.

[0220] In this regard, an RU smaller than the smallest bandwidth used in the mmWave band (e.g., 20*N MHz, 40*N MHz) can be defined, and a signal can be transmitted based on the said RU. In this case, power boosting may be applied when transmitting a signal based on the said RU.

[0221] The RU may consist of continuous subcarriers or discontinuous subcarriers. Transmission through the RU may apply to all fields of the PPDU or to only some fields. For example, transmission through the RU may apply only to data fields within the PPDU.

[0222] 2) Frequency domain repetition

[0223] The same signal may be transmitted repeatedly in specific size units. For example, the same signal may be repeated in units of the smallest bandwidth used in the mmWave band (e.g., 20*N MHz, 40*N MHz). Such repetition may be applied to all fields of the PPDU, or to only some fields. For example, such repetition may be applied only to the SIG / data fields within the PPDU.

[0224] As another example, a smaller RU may be defined within the smallest bandwidth used in the mmWave band (e.g., 20*N MHz, 40*N MHz), and the aforementioned iteration may be performed on the unit of that RU. That RU may consist of continuous subcarriers or discontinuous subcarriers. Iteration / transmission through that RU may be applied to all fields of the PPDU or to only some fields. For example, iteration / transmission through that RU may be applied only to the data fields within the PPDU.

[0225] 3) Time domain repetition

[0226] The same signal can be transmitted repeatedly in specific symbol / time units. For example, two consecutive symbols can be repeated as the same signal.

[0227] When applied to an STF, the STF may have a longer length than the STF of the basic PPDU. For example, the STF may have twice the length of the STF of the basic PPDU.

[0228] When applied to an LTF, the LTF may consist of a number of symbols that is a specific multiple or greater than the number of LTF symbols required for conventional spatial stream transmission. In this case, similar to transmitting multiple streams, coefficients of the P-matrix and R-matrix may be applied to the data tones and pilot tones of the LTF.

[0229] For example, when transmitting two spatial streams, an LTF with two symbols can be configured by default. This implies that, in the case of considering a GI*2+LTS+LTS structure, the number of additional LTF symbols (GI+LTS or GI*2+LTS+LTS) is one. In this case, if configured with twice the number of LTF symbols, the LTF can consist of four symbols. This implies that, in the case of considering a GI*2+LTS+LTS structure, the number of additional LTF symbols (GI+LTS or GI*2+LTS+LTS) is two. In this case, similar to transmitting four spatial streams, the coefficients of the P matrix and R matrix can be applied to the data tone and pilot tone of the LTF. In the case of considering a GI*2+LTS+LTS structure, the P matrix and R matrix are applied to the corresponding LTS as if they were a single symbol, and from the additional LTF symbols onwards, the P matrix and R matrix for a multi-stream situation can be applied.

[0230] In addition, in the case of transmission for an extended range, the number of symbols in the LTF can be fixed to a specific number. For example, the length of the LTF can be fixed to 2 symbols, 4 symbols, or 8 symbols. This means that in the case of considering the GI*2+LTS+LTS structure, the number of additional LTF symbols may be 1, 3, or 7.

[0231] When applied to SIGs, if a SIG in a basic PPDU consists of multiple symbols, the SIG may have a structure in which the same SIG structure is repeated twice, or a structure in which each symbol is repeated twice. For example, if the basic SIG has the structure "SIG1 | SIG2", the PPDU for the extended range may have the structure "SIG1 | SIG2 | SIG1 | SIG2" by applying the former method, or the structure "SIG1 | SIG1 | SIG2 | SIG2" by applying the latter method.

[0232] When applied to a data field, the same signal may be repeated in units of specific symbols. Alternatively, the same symbol may be placed after each symbol. For example, assuming units of 2 symbols, the data field may have a structure of "sym1 | sym2 | sym1 | sym2 | sym3 | sym4 | sym3 | sym4 ..." in the former case, and a structure of "sym1 | sym1 | sym2 | sym2 | sym3 | sym3 | sym4 | sym4 ..." in the latter case.

[0233] In situations where applied to SIG and / or data fields, specific phase rotation may be applied to repeating symbols, which can improve performance.

[0234] 4) Low MCS application

[0235] For PPDUs for extended range, an MCS with a lower data rate than the lowest data rate MCS applied to the basic PPDU may be applied. For example, if BPSK 1 / 2 is the lowest data rate MCS applied to the basic PPDU, then the MCS of BPSK 1 / 2 with dual carrier modulation (DCM) applied may be applied to the PPDU for extended range. The application of a lower MCS may be applied to the SIG and / or data fields.

[0236] Based on one or more of the various options described above, the PPDU for extended range can be configured as a PPDU structure such as FIG. 13 based on the basic PPDU structure.

[0237] FIG. 13 shows an example of a PPDU format for an extended range in the mmWave band according to an embodiment of the present disclosure.

[0238] Referring to FIG. 13, the PPDU format may be configured to include STF, LTF, SIG, ER(Extended Range)-STF, ER-LTF, ER-SIG, and ER-Data fields.

[0239] Here, STF, LTF, and SIG may be identical to the basic PPDU structure (e.g., the PPDU structure of FIG. 12), and the ER-STF, ER-LTF, ER-SIG, and ER-Data fields may correspond to fields configured based on one or more of the various options described above.

[0240] Additionally, a mark symbol may be applied / added between SIG and ER-STF. The mark symbol may indicate that it is a PPDU for an extended range. For example, the mark symbol may be conveyed / configured with information such as BSS color.

[0241] Additionally, various methods can be considered as signaling to indicate that it is a PPDU for the aforementioned extended range.

[0242] In cases where the PPDU structure is not new—that is, where the various options described above have been applied to the basic PPDU structure—an indication that it is a PPDU for an extended range may be made in the STF. For example, to this end, the length of the STF and a specific signature may be used. Alternatively, the PPDU type may be indicated in the SIG. In this regard, it may be desirable to make such an indication in the STF to determine the number of LTF symbols.

[0243] For a new PPDU structure (e.g., the PPDU structure of FIG. 13), the PPDU type may be indicated in the SIG. Alternatively, a specific mark symbol located between the SIG and ER-STF may be applied to indicate that it is a PPDU for an extended range.

[0244] Alternatively, information indicating that it is a PPDU for extended range may be transmitted / instructed in the sub-7 GHz band (e.g., 2.4 GHz / 5 GHz / 6 GHz band, etc.) before transmitting the PPDU.

[0245] Regarding the aforementioned basic PPDU format and / or PPDU format for an extended range, a method utilizing signaling in the sub-7 GHz band to indicate the number of LTF symbols may be considered. However, STA(s) that do not receive such signaling in the sub-7 GHz band cannot know the number of LTF symbols and, consequently, may not be able to perform decoding for the PPDU.

[0246] Considering these problems and the overhead associated with such signaling, the present disclosure proposes a method for using / defining a fixed number of LTF symbols for PPDU formats in the mmWave band.

[0247] Example 3

[0248] This embodiment relates to a method for applying a fixed number of LTF symbols to the PPDU format in the mmWave band.

[0249] For example, a case may be considered in which the maximum number of spatial streams applicable to a mmWave band PPDU is defined as 1 (hereinafter referred to as Case 1 for convenience of explanation). In this case, the number of LTF symbols may always be 1, which may mean that there are no additional LTF symbols when considering the GI*2+LTS+LTS structure. Alternatively, for reliability, the LTF may be fixed to have two or more symbols. For example, the number of LTF symbols may be 1, 3, or 7, which may mean that there are 1, 3, or 7 additional LTF symbols when considering the GI*2+LTS+LTS structure. Here, the additional LTF symbols may be GI+LTS.

[0250] In this regard, using one symbol may be desirable in terms of LTF overhead, and using four or eight symbols may be desirable in terms of performance. When considering the trade-off, using two symbols may be desirable.

[0251] As another example, a case may be considered in which the maximum number of spatial streams applicable to a mmWave band PPDU is defined as 2 (hereinafter referred to as Case 2 for convenience of explanation). In this case, the number of LTF symbols can always be 2, which means that the number of additional LTF symbols is 1 when considering the GI*2+LTS+LTS structure. Alternatively, for reliability, the LTF may be fixed to have more than 2 symbols. For example, the number of LTF symbols can be 4 or 8, which means that the number of additional LTF symbols is 3 or 7 when considering the GI*2+LTS+LTS structure.

[0252] In this regard, using 2 symbols may be desirable in terms of LTF overhead, and using 8 symbols may be desirable in terms of performance. When considering the trade-off, using 4 symbols may be desirable.

[0253] Additionally or alternatively, depending on the type of PPDU, LTFs may be configured / defined with different number of symbols. For example, for a PPDU for beamforming training (e.g., a PPDU for SLS) or a PPDU for extended range, in cases 1 and 2, an LTF with a fixed number of 2 or more symbols and an LTF with a fixed number of more than 2 symbols may be configured / defined, respectively. Here, for an LTF with a fixed number of 2 or more symbols, the number of LTF symbols may be 2, 4, or 8, which means that the additional number of LTF symbols is 1, 3, or 7 when considering the GI*2+LTS+LTS structure. Also, for an LTF with a fixed number of more than 2 symbols, the number of LTF symbols may be 4 or 8, which means that the additional number of LTF symbols is 3 or 7 when considering the GI*2+LTS+LTS structure. For a PPDU to which beamforming, etc. is applied, in case 1 and case 2, the number of LTF symbols can be fixed to 1 or 2, respectively.

[0254] An LTF can be constructed using a predefined P matrix based on the number of symbols in the LTF. For example, the coefficients of the P matrix and R matrix can be applied to data tones and pilot tones. In a situation considering a GI*2+LTS+LTS structure, the P matrix and R matrix can be applied to the LTSs as if they were a single symbol, and the P matrix and R matrix in a multi-stream situation can be applied starting from additional LTF symbols.

[0255] Additionally, or alternatively, when constructing additional LTF symbols by considering GI*2+LTS+LTS as a single symbol, a form that repeats the structure may be considered. For example, the fact that an LTF symbol consists of two symbols may imply a structure of GI*2+LTS+LTS+GI*2+LTS+LTS. Furthermore, the P matrix and R matrix may be applied based on existing rules by considering GI*2+LTS+LTS as a single LTF symbol.

[0256] Hereinafter, the operation of the STA according to the embodiment of the present disclosure described above will be explained with reference to FIGS. 14 and 15. That is, the examples of FIGS. 14 and 15 may correspond to some of the various examples of the present disclosure.

[0257] FIG. 14 illustrates the operation of a first STA according to an embodiment of the present disclosure.

[0258] The first STA can configure a PPDU (physical layer protocol data unit) in a specific frequency band (S1410).

[0259] In this regard, the specific frequency band may be a mmWave band or a 60 GHz band. Additionally, the PPDU may include at least one of a first STF portion, a first LTF portion, a first SIG portion, a second STF portion, a second LTF portion, a second SIG portion, or a data portion.

[0260] That is, the PPDU configured in step S1410 may be based on the PPDU format for an extended range in the mmWave band described above in this disclosure (e.g., FIG. 13). For example, the structure of the PPDU is defined in relation to the operation for the extended range, in which case the second STF portion, the second LTF portion, the second SIG portion, and the data portion may be related to the operation for the extended range.

[0261] The first STA can transmit the corresponding PPDU to the second STA (S1420).

[0262] In this regard, the data portion within the PPDU may be configured based on an RU size smaller than the smallest bandwidth supported in a specific frequency band. For example, the smallest bandwidth corresponds to 20*N MHz or 40*N MHz, where N represents the value of the upclocking factor applied to the configuration of the PPDU.

[0263] According to the present disclosure, a PPDU is configured based on an upclocking element, and for said PPDU, the bandwidth is one of 20*N, 40*N, 80*N, or 160*N MHz, the subcarrier spacing is 312.5*N kHz, the number of subcarriers is one of 64, 128, 256, or 512, and the OFDM (orthogonal frequency division multiplexing) symbol length excluding the CP (cyclic prefix) length is 3.2 / N us, and N may correspond to the value of said upclocking element.

[0264] In addition, according to the present disclosure, the methods described below may be applied in relation to the configuration of the said PPDU.

[0265] For example, the data portion can be transmitted by applying power boosting in the aforementioned RU size units.

[0266] For example, the data portion can be transmitted by applying repetition in the frequency domain based on the aforementioned RU size unit.

[0267] For example, the number of symbols in the first LTF portion and the number of symbols in the second LTF portion can each be fixed (to the same value or a different value), and the number of symbols in the second LTF portion can be set to a value greater than or equal to 2 depending on the maximum number of spatial streams. Additionally, the number of symbols in the first LTF portion can be set to 1 or 2 depending on the maximum number of spatial streams.

[0268] For example, the second STF portion may be configured to have a longer length than the first STF portion.

[0269] Additionally, according to the present disclosure, within the said PPDU, at least one symbol (e.g., a mark symbol) for indicating the type of said PPDU may be located between the first SIG portion and the second STF portion.

[0270] Additionally, according to the present disclosure, if the PPDU includes one or more of a second STF portion, a second LTF portion, a second SIG portion, or a data portion (e.g., if the PPDU is for an extended range), the type of the PPDU may be indicated by the first SIG portion.

[0271] The method performed by the first STA described in the example of FIG. 14 can be performed by the first device (100) of FIG. 1. For example, one or more processors (102) of the first device (100) of FIG. 1 may be configured to configure a PPDU in a specific frequency band and to transmit the configured PPDU to the second STA (200) through one or more transceivers (106). For example, as described above, one or more processors (102) of the first device (100) may configure a PPDU for an extended range in the mmWave band by encoding a first STF portion, a first LTF portion, a first SIG portion, a second STF portion, a second LTF portion, a second SIG portion, and / or a data portion.

[0272] Furthermore, one or more memories (104) of the first device (100) may store instructions for performing the method described in the example of FIG. 14 or the examples described above when executed by one or more processors (102).

[0273] FIG. 15 illustrates the operation of a second STA according to an embodiment of the present disclosure.

[0274] The second STA can receive a PPDU (physical layer protocol data unit) in a specific frequency band (S1510).

[0275] In this regard, the specific frequency band may be a mmWave band or a 60 GHz band. Additionally, the PPDU may include at least one of a first STF portion, a first LTF portion, a first SIG portion, a second STF portion, a second LTF portion, a second SIG portion, or a data portion.

[0276] That is, the PPDU received in step S1510 may be based on the PPDU format for an extended range in the mmWave band described in the present disclosure (e.g., FIG. 13). For example, the structure of the PPDU is defined in relation to the operation for the extended range, in which case the second STF portion, the second LTF portion, the second SIG portion, and the data portion may be related to the operation for the extended range.

[0277] In this regard, the data portion may be configured based on a RU size smaller than the smallest bandwidth supported in a specific frequency band.

[0278] The second STA can process the received PPDU (S1520).

[0279] For example, processing of a PPDU may include obtaining information contained in each of the fields of a received PPDU based on one of various predetermined PPDU formats (e.g., a PPDU format for an extended range in the mmWave band, etc.).

[0280] In the example of FIG. 15, specific details regarding the application of upclocking elements, setting and application of a specific RU size, power boosting, repetition in the frequency domain, number of LTF symbols, STF length, and instructions for PPDU types for extended range are the same as those described in the example of FIG. 14, so redundant descriptions are omitted.

[0281] The method performed by the second STA described in the example of FIG. 15 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 in a specific frequency band from the first STA (100) through one or more transceivers (206) and may be configured to process the received PPDU. For example, one or more processors (202) of the second device (200) may be configured to decode the received PPDU based on a PPDU format defined for an extended range in the mmWave band to obtain information contained in a first STF portion, a first LTF portion, a first SIG portion, a second STF portion, a second LTF portion, a second SIG portion, and / or a data portion.

[0282] Furthermore, one or more memories (204) of the second device (200) may store instructions for performing the method described in the example of FIG. 15 or the examples described above when executed by one or more processors (202).

[0283] The present disclosure relates to a specific method for newly defining and configuring a PPDU format for an extended range in the mmWave band, which is not defined in existing wireless LAN systems. According to the method proposed in the present disclosure, new effects can be achieved to improve throughput and / or efficiency in the newly defined operating band (e.g., mmWave band, etc.).

[0284] 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.

[0285] 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.

[0286] 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.

[0287] 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 first station (STA) in a wireless LAN system, wherein the method comprises: A step of configuring a PPDU (physical layer protocol data unit) in a specific frequency band; and The step of transmitting the above PPDU to the second STA, wherein The above PPDU includes at least one of a first STF (short training field) portion, a first LTF (long training field) portion, a first signal (SIG) portion, a second STF portion, a second LTF portion, a second SIG portion, or a data portion. A method in which the above data portion is configured based on a resource unit (RU) size smaller than the smallest bandwidth supported in the above specific frequency band.

2. In Paragraph 1, The structure of the above PPDU is defined in relation to operation for an extended range, and The method, wherein the second STF portion, the second LTF portion, the second SIG portion, and the data portion are related to the operation of the extended range.

3. In Paragraph 1, The above smallest bandwidth corresponds to 20*N MHz or 40*N MHz, and A method in which N is the value of an upclocking factor applied to the configuration of the PPDU.

4. In Paragraph 1, The above PPDU is configured based on an upclocking element, and Regarding the above PPDU, The bandwidth is one of 20*N, 40*N, 80*N, or 160*N MHz, and The subcarrier spacing is 312.5*N kHz, and The number of subcarriers is one of 64, 128, 256, or 512, and The OFDM (orthogonal frequency division multiplexing) symbol length, excluding the CP (cyclic prefix) length, is 3.2 / N us, and The above N is a method corresponding to the value of the above upclocking element.

5. In Paragraph 1, The above specific frequency band corresponds to a millimeter wave (mmWave) band or a 60 GHz band, a method.

6. In Paragraph 1, A method in which the above data portion is transmitted by applying power boosting in the above RU size unit.

7. In Paragraph 1, A method in which the above data portion is transmitted by applying repetition in the frequency domain based on the above RU size unit.

8. In Paragraph 1, The number of symbols in the first LTF portion and the number of symbols in the second LTF portion are each fixed, and A method in which the number of symbols in the second LTF portion is set to a value greater than or equal to 2 according to the maximum number of spatial streams.

9. In Paragraph 8, A method in which the number of symbols in the first LTF portion is set to 1 or 2 depending on the maximum number of spatial streams.

10. In Paragraph 1, A method in which the second STF portion is configured to have a longer length than the first STF portion.

11. In Paragraph 1, A method in which at least one symbol for indicating the type of PPDU is located between the first SIG portion and the second STF portion.

12. In Paragraph 1, A method in which the type of the PPDU is indicated through the first SIG portion, based on the fact that the PPDU includes one or more of the second STF portion, the second LTF portion, the second SIG portion, or the data portion.

13. In a first 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: Configure a PPDU (physical layer protocol data unit) in a specific frequency band; Set the above PPDU to be transmitted to the second STA, but, The above PPDU includes at least one of a first STF (short training field) portion, a first LTF (long training field) portion, a first signal (SIG) portion, a second STF portion, a second LTF portion, a second SIG portion, or a data portion. A device configured based on a resource unit (RU) size smaller than the smallest bandwidth supported in the specific frequency band, wherein the above data portion is configured.

14. A method performed by a second station (STA) in a wireless LAN system, wherein the method comprises: A step of receiving a PPDU (physical layer protocol data unit) in a specific frequency band; and The step of processing the above PPDU is included, The above PPDU includes at least one of a first STF (short training field) portion, a first LTF (long training field) portion, a first signal (SIG) portion, a second STF portion, a second LTF portion, a second SIG portion, or a data portion. A method in which the above data portion is configured based on a resource unit (RU) size smaller than the smallest bandwidth supported in the above specific frequency band.

15. In a second 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: Receiving a PPDU (physical layer protocol data unit) in a specific frequency band; Set to process the above PPDU, but, The above PPDU includes at least one of a first STF (short training field) portion, a first LTF (long training field) portion, a first signal (SIG) portion, a second STF portion, a second LTF portion, a second SIG portion, or a data portion. A method in which the above data portion is configured based on a resource unit (RU) size smaller than the smallest bandwidth supported in the above specific frequency band.

16. In a processing unit configured to control a station (STA) in a wireless LAN system, the processing unit comprises: One or more processors; and A processing unit 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 12 based on execution by one or more processors.

17. 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 station (STA) device in a wireless LAN system to perform a method according to any one of claims 1 to 12.

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