Method and apparatus for transmitting and receiving PPDU based on guard interval in wireless LAN system

Abstract

Disclosed are a method and an apparatus for transmitting or receiving a physical layer protocol data unit (PPDU) based on a guard interval in a wireless LAN system. According to one embodiment of the present disclosure, a method performed by a first station (STA) in a wireless LAN system comprises the steps of: receiving, from a second STA, a physical layer protocol data unit (PPDU) including a first one or more fields and a second one or more fields, the first one or more fields include one or more non-legacy signal (SIG) fields and the second one or more fields include a data field; and decoding the first one or more fields and the second one or more fields, and obtaining a Media Access Control Protocol Data Unit (MPDU) based on the data field, where a guard interval value for the second one or more fields may be predefined as a single value.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for transmitting or receiving a guard interval-based physical layer protocol data unit (PPDU) in a wireless local area network (WLAN) system. Background Art

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

[0003] In order to provide a more complete wireless communication environment, enhanced technologies for EHT (Extremely High Throughput) are being discussed. For example, technologies for supporting increased bandwidth, effective use of multiple bands, and increased spatial streams, multi-access point (AP) coordination and multiple-input multiple-output (MIMO) are being studied, and in particular, various technologies for supporting low-latency or real-time services are being studied. In addition, new technologies that support ultra-high reliability (UHR) by including improvements or extensions of EHT technology are being discussed. Summary of the invention

[0004] Technical issues

[0005] A technical problem of the present disclosure is to provide a method and apparatus for transmitting or receiving a PPDU based on a guard interval applied to different fields of the PPDU in a WLAN system.

[0006] An additional technical problem of the present disclosure is to provide a method and apparatus for defining a guard interval for a portion including a data field of a PPDU in a WLAN system.

[0007] The technical objectives achieved by the present disclosure are not limited to the above-mentioned technical objectives, and other technical objectives not described herein will be clearly understood by those skilled in the relevant art from the following description.

[0008] Technical Solution

[0009] A method performed by a first station (STA) in a WLAN system according to one aspect of the present disclosure includes: receiving a physical layer protocol data unit (PPDU) including a first at least one field and a second at least one field from a second STA, wherein the first at least one field includes at least one non-legacy signal (SIG) field and the second at least one field includes a data field; and decoding the first at least one field and the second at least one field and obtaining a medium access control protocol data unit (MPDU) based on the data field, wherein a guard interval for the second at least one field may be predefined as a single value.

[0010] A method performed by a second station (STA) in a WLAN system according to another aspect of the present disclosure includes encoding a first at least one field including at least one non-legacy signal (SIG) field and a second at least one field including a data field, the data field including a medium access control protocol data unit (MPDU); and sending a physical layer protocol data unit (PPDU) including the first at least one field and the second at least one field to the first STA, wherein a guard interval for the second at least one field may be predefined as a single value.

[0011] Beneficial Effects

[0012] According to the present disclosure, a method and apparatus for transmitting or receiving a PPDU based on a guard interval applied to different fields of the PPDU in a WLAN system may be provided.

[0013] According to the present disclosure, a method and apparatus for defining a guard interval for a portion including a data field of a PPDU in a WLAN system may be provided.

[0014] Effects achievable by the present disclosure are not limited to the above-described effects, and other effects not described herein may be clearly understood by those skilled in the art through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are included as a part of the detailed description for understanding the present disclosure, provide embodiments of the present disclosure and describe technical features of the present disclosure through the detailed description.

[0016] Figure 1 A block configuration diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0017] Figure 2 is a diagram illustrating an exemplary structure of a WLAN system to which the present disclosure can be applied.

[0018] Figure 3 is a diagram for describing a link setting process to which the present disclosure can be applied.

[0019] Figure 4 is a diagram for describing a backoff process to which the present disclosure can be applied.

[0020] Figure 5 is a diagram for describing a CSMA / CA-based frame transmission operation to which the present disclosure may be applied.

[0021] Figure 6 is a diagram for describing an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0022] Figure 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0023] Figures 8 to 10 is a diagram for explaining an example of a resource unit of a WLAN system to which the present disclosure can be applied.

[0024] Fig.11 is a diagram showing an example of a channelized area of ​​a millimeter wave band to which the present disclosure can be applied.

[0025] Fig.12 is a flowchart for describing a PPDU receiving method according to the present disclosure.

[0026] Fig.13 is a flowchart for describing a PPDU transmission method according to the present disclosure. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description to be disclosed by the accompanying drawings is intended to describe exemplary embodiments of the present disclosure, rather than to represent the only embodiment in which the present disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art will appreciate that the present disclosure can be implemented without these specific details.

[0028] In some cases, well-known structures and devices may be omitted, or may be shown in the form of a block diagram based on the core functions of each structure and device in order to prevent ambiguity in the concepts of the present disclosure.

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

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

[0031] The terms used in this disclosure are intended to describe specific embodiments rather than to limit the claims. As used in the description of the embodiments and the appended claims, the singular form is intended to include the plural form unless the context clearly indicates otherwise. The term "and / or" used in this disclosure may refer to one of the related enumerated items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise stated, the " / " between words in this disclosure has the same meaning as "and / or".

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

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

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

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

[0036] Figure 1 The devices 100 and 200 illustrated in FIG. 1 may be referred to as stations (STAs). For example, Figure 1 The devices 100 and 200 illustrated in the figure may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, STA110 and 200 may perform an access point (AP) role or a non-AP role. That is, in the present disclosure, STA 110 and 200 may perform the functions of an AP and / or a non-AP. When STA 110 and 200 perform an AP function, they may be referred to as AP for short, and when STA 110 and 200 perform a non-AP function, they may be referred to as STA for short. In addition, in the present disclosure, an AP may also be indicated as an APSTA.

[0037] refer to Figure 1 , the first device 100 and the second device 200 can transmit and receive radio signals through various wireless LAN technologies (eg, IEEE802.11 series). The first device 100 and the second device 200 may include interfaces for a media access control (MAC) layer and a physical layer (PHY) conforming to the IEEE802.11 standard.

[0038] In addition, the first device 100 and the second device 200 may additionally support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) technologies other than wireless LAN technology. In addition, the device of the present disclosure may be implemented in various devices, such as mobile phones, vehicles, personal computers, augmented reality (AR) devices, virtual reality (VR) devices, etc. In addition, the STA of the present specification may support various communication services, such as voice calls, video calls, data communications, autonomous driving, machine type communications (MTC), machine to machine (M2M), device to device (D2D), IoT (Internet of Things), etc.

[0039] The first device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106 and may be configured to implement the description, function, process, proposal, method and / or operation flow chart disclosed in the present disclosure. For example, the processor 102 may send a wireless signal including the first information / signal through the transceiver 106 after generating the first information / signal by processing the information in the memory 104. In addition, the processor 102 may receive a wireless signal including the second information / signal through the transceiver 106, and then store the information obtained by the signal processing of the second information / signal in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for executing all or part of the process controlled by the processor 102 or for executing the description, function, process, proposal, method and / or operation flow chart disclosed in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., LTE 802.11 series). The transceiver 106 may be connected to the processor 102 and may send and / or receive wireless signals through one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used in conjunction with an RF (radio frequency) unit. In the present disclosure, a device may refer to a communication modem / circuit / chip.

[0040] The second device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the description, function, process, proposal, method and / or operation flow chart disclosed in the present disclosure. For example, the processor 202 may generate third information / signal by processing the information in the memory 204, and then send a wireless signal including the third information / signal through the transceiver 206. In addition, the processor 202 may receive a wireless signal including fourth information / signal through the transceiver 206, and then store the information obtained by 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 including instructions for executing all or part of the process controlled by the processor 202 or for executing the description, function, process, proposal, method and / or operation flow chart disclosed in the present 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 send and / or receive wireless signals through one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used in conjunction with an RF unit. In the present disclosure, a device may refer to a communication modem / circuit / chip.

[0041] In the following, the hardware elements of the device 100, 200 will be described in more detail. It is not limited thereto, but one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors 102, 202 may generate one or more PDUs (protocol data units) and / or one or more SDUs (service data units) according to the description, function, process, proposal, method, and / or operation flow chart disclosed in the present disclosure. One or more processors 102, 202 may generate messages, control information, data, or information according to the description, function, process, proposal, method, and / or operation flow chart disclosed in the present disclosure. One or more processors 102, 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, processes, proposals, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106, 206. The one or more processors 102, 202 may receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in the present disclosure.

[0042] One or more processors 102, 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. In an example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102, 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts included in the present disclosure may be implemented using firmware or software and the firmware or software may be implemented to include modules, processes, functions, etc. Firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operational flowcharts included in the present disclosure may be included in one or more processors 102, 202 or may be stored in one or more memories 104, 204 and driven by one or more processors 102, 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts included in the present disclosure may be implemented by firmware or software in the form of codes, commands, and / or command sets.

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

[0044] One or more transceivers 106, 206 may send user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operation flow charts, 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. mentioned in the descriptions, functions, processes, proposals, methods, and / or operation flow charts, etc. included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may send and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to send user data, control information, or wireless signals to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. In addition, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to send and receive user data, control information, wireless signals / channels, etc. mentioned in the description, functions, processes, proposals, methods and / or operation flow charts, etc. included in the present disclosure through one or more antennas 108, 208. In the present invention, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert received wireless signals / channels, etc. from RF band signals to baseband signals by using one or more processors 102, 202 to process received user data, control information, wireless signals / channels, etc. One or more transceivers 106, 206 may convert user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals to RF band signals. Therefore, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

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

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

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

[0048] The structure of a wireless LAN system may consist of multiple components. A wireless LAN that supports STA mobility transparent to upper layers may be provided through the interaction of multiple components. A basic service set (BSS) corresponds to a basic building block of a wireless LAN. Figure 2 It is exemplarily shown that two BSSs (BSS1 and BSS2) exist and two STAs are included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2 The ellipse representing the BSS in FIG. 1 may also be understood to represent a coverage area in which the STAs included in the corresponding BSS maintain communication. This area may be referred to as a basic service area (BSA). When a STA moves out of a BSA, it cannot directly communicate with other STAs in the BSA.

[0049] If you don't consider Figure 2 , the most basic type of BSS in a wireless LAN is an independent BSS (IBSS), if the DS shown in is included. For example, an IBSS may have a minimal form containing only two STAs. For example, assuming that other components are omitted, BSS1 containing only STA1 and STA2 or BSS2 containing only STA3 and STA4 may correspond to representative examples of IBSSs, respectively. This configuration is possible when STAs can communicate directly without an AP. In addition, in this type of wireless LAN, it is not configured in advance but can be configured when a LAN is needed, and this may be referred to as a self-organizing network. Because the IBSS does not include an AP, there is no centralized management entity. That is, in the IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs may be composed of mobile STAs, and access to a distributed system (DS) is not allowed, thereby forming a self-contained network.

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

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

[0052] DS means a structure in which BSSs are interconnected. Specifically, Figure 2As shown in , the BSS can exist as an extended form of a network composed of multiple BSSs. DS is a logical concept and can be specified by the characteristics of the distributed system medium (DSM). In this regard, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for a different purpose and is used by different components. These media are not limited to being the same or different. In this way, the flexibility of the wireless LAN structure (DS structure or other network structure) can be explained by the logical difference of multiple media. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be independently specified by the physical characteristics of each embodiment.

[0053] DS can support mobile devices by providing seamless integration of multiple BSSs and providing logical services necessary to address addresses to destinations. In addition, DS can further include a component called a portal, which serves as a bridge for connection between wireless LAN and other networks (e.g., IEEE 802.X).

[0054] The AP enables access to the DS through the WM for the associated non-AP STAs and means an entity that also has the functionality of a STA. Data movement between the BSS and the DS can be performed by the AP. For example, Figure 2 STA2 and STA3 shown in the figure have the functionality of STA and provide the function of allowing the associated non-AP STA (STA1 and STA4) to access the DS. In addition, because all APs basically 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 are not necessarily the same. A BSS composed of an AP and one or more STAs can be called an infrastructure BSS.

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

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

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

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

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

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

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

[0062] Scanning schemes include active scanning and passive scanning. Figure 3The network discovery operation including the active scanning process is exemplarily illustrated. In active scanning, the STA performing the scan sends a probe request frame while moving the channel to find out which APs exist around it and wait for a response thereto. The responder sends a probe response frame to the STA that has sent the probe request frame as a response to the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the scanned channel. In the BSS, because the AP sends a beacon frame, the AP becomes the responder, and in the IBSS, the STAs in the IBSS take turns sending beacon frames, so the responder is not constant. For example, a STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 may store the BSS-related information included in the received probe response frame, and may move to the next channel (e.g., channel 2) and perform scanning in the same manner (i.e., transmission / reception of probe requests / responses on channel 2).

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

[0064] After the STA discovers the network, an authentication process may be performed in step S320. In order to clearly distinguish it from the security setup operation of step S340 to be described later, this authentication process may be referred to as a first authentication process.

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

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

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

[0068] After the STA is successfully authenticated, an association process may be performed in step S330. The association process includes a process in which the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0069] For example, the association request frame may include information related to various capabilities, beacon listening interval, service set identifier (SSID), supported rates, supported channels, RSN, mobile domain, supported operation category, traffic indication map broadcast request (TIM broadcast request), interworking service capabilities, etc. For example, the association response frame may include information related to various capabilities, status code, association ID (AID), supported rates, enhanced distributed channel access (EDCA) parameter set, received channel power indicator (RCPI), received signal-to-noise ratio indicator (RSNI), mobile domain, timeout interval (e.g., association recovery time), overlapping BSS scanning parameters, TIM broadcast response, quality of service (QoS) map, etc. This corresponds to some examples of information that may be included in the association request / response frame, and may be replaced with other information, or may further include additional information.

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

[0071] The security setup process of step S340 may include, for example, a process of establishing a private key through a 4-way handshake of an Extensible Authentication Protocol over LAN (EAPOL) frame. In addition, the security setup process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

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

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

[0074] In addition, the IEEE 802.11 MAC protocol provides a hybrid coordination function (HCF). HCF is based on DCF and point coordination function (PCF). PCF is a polling-based synchronous access method, and refers to a method in which all receiving APs and / or STAs periodically poll to receive data frames. In addition, HCF has enhanced distributed channel access (EDCA) and HCF-controlled channel access (HCCA). EDCA is a contention-based access method for a provider to provide data frames to multiple users, and HCCA uses a non-contention-based channel access method using a polling mechanism. In addition, HCF includes a media access mechanism for improving the QoS (Quality of Service) of a wireless LAN, and QoS data can be sent in both a contention period (CP) and a contention-free period (CFP).

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

[0076] When the random backoff process starts, the STA continuously monitors the medium while counting down the backoff slot according to the determined backoff count value. When it detects that the medium is occupied, it stops the countdown and waits, and when the medium becomes idle, it resumes the remaining countdown.

[0077] exist Figure 4 In the example of , when the packet to be sent arrives at the MAC of STA3, STA3 can send the frame immediately after confirming that the medium is idle for as much as DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. At the same time, data to be sent may also occur in each of STA1, STA2 and STA5, and when the medium is monitored as idle, each STA waits as long as DIFS, and then the backoff slot can be counted down according to the random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, the case where the remaining backoff time of STA5 is less than the remaining backoff time of STA1 when STA2 completes the backoff count and starts frame transmission is illustrated. STA1 and STA5 temporarily stop the countdown and wait while STA2 occupies the medium. When STA2 occupancy ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and resume the stopped backoff count. That is, after counting down the remaining backoff slot within the remaining backoff time, frame transmission can be started. Because the remaining backoff time of STA5 is less than that of STA1, STA5 starts frame transmission. While STA2 occupies the medium, data to be sent may also appear in STA4. From the perspective of STA4, when the medium becomes idle, STA4 can wait for DIFS, and then perform a countdown according to the random backoff count value selected by STA4 and start sending frames. Figure 4 The example shows a case where the remaining backoff time of STA5 coincides with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, so data transmission fails. 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 the transmission of STA4 and STA5, waits for DIFS when the medium becomes idle, and then starts frame transmission after the remaining backoff time has elapsed.

[0078] like Figure 4As shown in the example of , a data frame is a frame for transmitting data forwarded to a higher layer, and may be sent after performing a backoff after DIFS has elapsed from when the medium becomes idle. In addition, a management frame is a frame for exchanging management information that is not forwarded to a higher layer, and is sent after performing a backoff after an IFS such as DIFS or a point coordination function IFS (PIFS). As subtype frames of the management frame, there are beacons, association request / responses, reassociation request / responses, probe request / responses, authentication request / responses, and the like. A control frame is a frame for controlling access to a medium. As subtype frames of the control frame, there are request to send (RTS), clear to send (CTS), acknowledgement (ACK), power save poll (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), empty data packet announcement (NDP announcement), and triggers, and the like. If the control frame is not a response frame of a previous frame, it is sent after performing a backoff after DIFS has elapsed, and if it is a response frame of a previous frame, it is sent without performing a backoff after a short IFS (SIFS) has elapsed. The type and subtype of a frame can be identified by the type field and subtype field in the frame control (FC) field.

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

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

[0081] As described above, the CSMA / CA mechanism includes virtual carrier sensing in addition to the physical carrier sensing in which the STA directly senses the medium. Virtual carrier sensing is intended to compensate for problems that may occur in media access, such as hidden node problems. For virtual carrier sensing, the STA's MAC can use a network allocation vector (NAV). NAV is a value that indicates to other STAs the remaining time until the medium is available for use by the STA that is currently using or has the right to use the medium. Therefore, the value set to NAV corresponds to the period in which the medium is scheduled for use by the STA that sends the frame, and the STA that receives the NAV value is prohibited from accessing the medium during the corresponding period. For example, the NAV can be configured based on the value of the "Duration" field of the MAC header of the frame.

[0082] exist Figure 5In the example of FIG. 1 , it is assumed that STA1 intends to send data to STA2, and STA3 is in a position to eavesdrop on some or all frames sent and received between STA1 and STA2.

[0083] In order to reduce the possibility of transmission conflicts between multiple STAs in CSMA / CA-based frame transmission operations, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example of , while STA1's transmission is being performed, as a result of STA3's carrier sensing, it can be determined that the medium is in an idle state. That is, STA1 may correspond to a hidden node of STA3. Alternatively, Figure 5 In the example of , it can be determined that the carrier sensing result medium of STA3 is in an idle state while the transmission of STA2 is performed. That is, STA2 may correspond to a hidden node of STA3. By performing the exchange of RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of one of STA1 or STA2, or STAs outside the carrier sensing range for transmission from STA1 or STA3 may not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[0084] 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 level or signal correlation detected in the channel. In addition, in terms of virtual carrier sensing, STA1 can use the network allocation vector (NAV) timer to determine the channel occupancy state.

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

[0086] If STA3 cannot eavesdrop on the CTS frame from STA2 but can eavesdrop on the RTS frame from STA1, STA3 can set the NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame) using the duration information included in the RTS frame. Alternatively, if STA3 can eavesdrop on the CTS frame from STA2, although STA3 cannot eavesdrop on the RTS frame from STA1, STA3 can set the NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS+data frame+SIFS+ACK frame) using the duration information included in the CTS frame. That is, if STA3 can eavesdrop on one or more of the RTS or CTS frames from one or more of STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access before the NAV timer expires.

[0087] When STA1 receives a CTS frame from STA2, STA1 may send a data frame to STA2 after SIFS from the time point when reception of the CTS frame is completed. When STA2 successfully receives the data frame, STA2 may send an ACK frame to STA1 as a response to the data frame after SIFS. STA3 may determine whether the channel is being used by carrier sensing when the NAV timer expires. When STA3 determines that the channel is not being used by other terminals during DIFS after the NAV timer expires, STA3 may attempt channel access after a contention window (CW) according to random backoff has elapsed.

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

[0089] With the help of instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MAC PDU (MPDU) to be sent. For example, when receiving a command requesting the PHY layer to start transmission from the MAC layer, the PHY layer switches to the transmission mode and configures the information (e.g., data) provided from the MAC layer in the form of a frame and sends it. In addition, when the PHY layer detects a valid preamble of the received frame, the PHY layer monitors the header of the preamble and sends a command to the MAC layer notifying the PHY layer of the start of reception.

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

[0091] The basic PPDU frame may include a short training field (STF), a long training field (LTF), a signal (SIG) field, and a data field. The most basic PPDU format (e.g., Figure 7 The non-HT (high throughput) shown in the PPDU format may consist of only the legacy STF (L-STF), the legacy LTF (L-LTF), the legacy SIG (L-SIG) field and the data field. In addition, depending on the type of PPDU format (e.g., HT mixed format PPDU, HT-greenfield format PPDU, VHT (very high throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)), etc. may be included between the L-SIG field and the data field.

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

[0093] The SIG field may include various information related to the transmission and reception of the PPDU. For example, the L-SIG field consists of 24 bits, and the L-SIG field may include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity field, and a 6-bit tail field. The RATE field may include information about the modulation and coding rate of the data. For example, the 12-bit length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit length field may be determined based on the type of 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.

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

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

[0096] The MAC header includes a frame control field, a duration / ID field, an address field, etc. The frame control field may include control information required for frame transmission / reception. The duration / ID field may be set to the time for transmitting the corresponding frame, etc. For detailed information on the sequence control, QoS control, and HT control subfields of the MAC header, please refer to the IEEE 802.11 standard document.

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

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

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

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

[0101] An example of a 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 (e.g. Figure 7 (shown in (c)).

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

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

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

[0105] Compared with EHT MU PPDU, Figure 7 The EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger (eg, a trigger frame or a trigger response schedule (TRS)) for UL MU transmission may perform UL transmission based on the EHT TB PPDU format.

[0106] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), EHT-SIG fields may be coded and modulated so that even legacy STAs may attempt to demodulate and decode, and may be mapped based on a determined subcarrier frequency interval (e.g., 312.5 kHz). These may be referred to as pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, Data, PE fields may be coded and modulated so that they may be demodulated and decoded by a STA that successfully decodes a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtains the information included in the field, and may be mapped based on a determined subcarrier frequency interval (e.g., 78.125 kHz). These may be referred to as EHT modulation fields.

[0107] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields may be referred to as HE modulation fields. In addition, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as free VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields may be referred to as VHT modulation fields.

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

[0109] U-SIG can be constructed in units of 20MHz. For example, if an 80MHz PPDU is constructed, the U-SIG may be repeated. That is, the same 4 U-SIGs may be included in the 80MHz PPDU. PPDUs with bandwidth exceeding 80MHz may include different U-SIGs.

[0110] For example, A uncoded bits may be sent via U-SIG, the first symbol of U-SIG (e.g., U-SIG-1 symbol) may send the first X bits of information out of a total of A bits of information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) may send the remaining Y bits of information out of a total of A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). For example, the tail field may be used to terminate a grid of a convolutional decoder and may be set to 0.

[0111] The bit information sent by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in Figure 7 In a new PPDU format not shown in the EHT PPDU format (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-related bits may be different.

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

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

[0114] For example, the version-related bits of the U-SIG may include information directly or indirectly indicating the PPDU type (eg, SUPPDU, MU PPDU, TB PPDU, etc.).

[0115] Information necessary for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information about bandwidth, information about an MCS technology applied to a non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether a DCM (dual carrier modulation) technology (e.g., a technology that achieves an effect similar to frequency diversity by repeatedly using the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and information about whether the non-legacy SIG is generated across the entire band, etc.

[0116] Some information necessary for PPDU transmission and reception may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-legacy LTF and the CP (cyclic prefix) length, information about the GI (guard interval) applicable to the non-legacy LTF, information about preamble puncturing applicable to the PPDU, information about RU (resource unit) allocation, etc. may be included only in the U-SIG, only in the non-legacy SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-legacy SIG.

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

[0118] exist Figure 7 In the example of , non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for receiving STAs. Non-legacy SIGs may be transmitted on at least one symbol, and one symbol may have a length of 4us. Information on the number of symbols used for EHT-SIG may be included in a previous SIG (eg, HE-SIG-A, U-SIG, etc.).

[0119] 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 compiled separately.

[0120] In some cases, the common field can be omitted. For example, in a compressed mode that does not apply OFDMA (Orthogonal Frequency Multiple Access), the common field can be omitted, and multiple STAs can receive PPDUs (e.g., data fields of PPDUs) through the same frequency band. In a non-compressed mode that applies OFDMA, multiple users can receive PPDUs (e.g., data fields of PPDUs) through different frequency bands.

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

[0122] The common field may include CRC bits and tail bits, and 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 about the locations of RUs assigned to multiple users (ie, multiple receiving STAs).

[0123] RU can include multiple subcarriers (or tones). RU can be used when sending signals to multiple STAs based on OFDMA technology. In addition, RU can be defined even when sending signals to one STA. Resources can be allocated in units of RU for non-legacy STF, non-legacy LTF and data fields.

[0124] The applicable size of RU can be defined according to the PPDU bandwidth. For the applied PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.), the RU can be defined the same or differently. For example, in the case of 80MHz PPDU, the RU placement of HEPPDU and EHT PPDU may be different. The applicable RU size, RU number and RU position, DC (direct current) subcarrier position and number, empty subcarrier position and number, protection subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, a tone plan for high bandwidth can be defined in the form of multiple iterations of a low bandwidth tone plan.

[0125] RUs of various sizes may be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2Х996-tone RUs, 3Х996-tone RUs, etc. MRUs (multiple RUs) are distinguished from multiple individual RUs and correspond to a group of subcarriers consisting of multiple RUs. For example, one MRU may be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2Х996+484 tones, 3Х996 tones, or 3Х996+484 tones. In addition, the multiple RUs constituting one MRU may or may not be continuous in the frequency domain.

[0126] The specific size of the RU may be reduced or enlarged. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in the present disclosure is not restrictive and is illustrative. In addition, in the present disclosure, within a predetermined bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...), the number of RUs may vary depending on the RU size.

[0127] Figure 7 The name of each field in the PPDU format is exemplary, and the scope of the present disclosure is not limited by the name. In addition, the examples of the present disclosure may be applied to Figure 7 The PPDU format shown in FIG. Figure 7 The PPDU format of the present invention excludes some fields and / or adds some fields to the new PPDU format.

[0128] Resource Unit

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

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

[0131] like Figures 8 to 10 As shown, RUs corresponding to different numbers of tones (i.e., subcarriers) are used to construct some fields of a 20 MHz, 40 MHz, or 80 MHz X-PPDU (X is HE, EHT, etc.). For example, resources can be allocated in RU units as shown for the X-STF, X-LTF, and data fields.

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

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

[0134] Figure 8 The RU allocation is utilized not only in the case of multi-user (MU) but also in the case of single user (SU), and in this case, a 242 unit can be used, such as Figure 8 In this case, three DC tones can be inserted.

[0135] exist Figure 8 In the examples of the present disclosure, various sizes of RUs, i.e., 26-RU, 52-RU, 106-RU, 242-RU, etc., are illustrated, but the specific sizes of these RUs may be reduced or enlarged. Therefore, in the present disclosure, the specific size of each RU (i.e., the number of corresponding tones) is exemplary and not restrictive. In addition, within the predetermined bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) of the present disclosure, the number of RUs may vary according to the size of the RU. In the following description, Fig. 9 and / or Fig.10 The fact that the size and / or number of RUs can vary is related to Figure 8 The same example.

[0136] Fig. 9 is a diagram illustrating an exemplary allocation of resource units (RUs) used on a 40 MHz band.

[0137] As in Figure 8 As in the example using various RU sizes, Fig. 9 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. may also be used in the example. In addition, 5 DC tones may be inserted at the center frequency, 12 tones may be used as a guard band in the leftmost band of the 40 MHz band, and 11 tones may be used as a guard band in the rightmost band of the 40 MHz band.

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

[0139] Fig.10 is a diagram illustrating an exemplary allocation of resource units (RUs) used on an 80 MHz band.

[0140] Just like in Figure 8 and Fig. 9 As in the example using various RU sizes, Fig.10 In the example of 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc., can also be used. In addition, in the case of 80MHz PPDU, the RU allocation of HE PPDU and EHT PPDU may be different, and Fig.10 The example of FIG. 1 shows an example of RU allocation for an 80 MHz EHT PPDU. Fig.10 The scheme of using 12 tones as a guard band in the leftmost band of the 80MHz band and 11 tones as a guard band in the rightmost band of the 80MHz band in the example is the same in the HE PPDU and the EHT PPDU. Unlike the HE PPDU, 7 DC tones are inserted in the DC band and there is one 26-RU corresponding to each of the 13 tones on the left and right sides of the DC band, in the EHT PPDU, 23 DC tones are inserted in the DC band, and there is one 26-RU on the left and right sides of the DC band. Unlike the HE PPDU, there are five empty subcarriers in the EHT PPDU, where there is one empty subcarrier between 242-RUs instead of between the center bands. In the HE PPDU, one 484-RU does not include an empty subcarrier, but in the EHT PPDU, one 484-RU includes 5 empty subcarriers.

[0141] Additionally, as shown, when used for a single user, 996-RU may be used, and in this case, 5 DC tones are inserted together with the HEPPDU and EHT PPDU.

[0142] The 160MHz EHT PPDU can be configured with Fig.10 The RU allocation for each 80MHz sub-block can be Fig.10 If the 80 MHz sub-block of a 160 MHz or 320 MHz EHT PPDU is not punctured and the entire 80 MHz sub-block is used as a RU or part of multiple RUs (MRU), the 80 MHz sub-block can be used Fig.10 The 996-RU.

[0143] Here, the MRU corresponds to a group of subcarriers (or tones) composed of multiple RUs, and the multiple RUs constituting the MRU may be RUs of the same size or RUs of different sizes. For example, a single MRU may be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2Х996+484 tones, 3Х996 tones, or 3Х996+484 tones. Here, the multiple RUs constituting one MRU may correspond to a small-size (e.g., 26, 52, or 106) RU or a large-size (e.g., 242, 484, or 996) RU. That is, one MRU including a small-size RU and a large-size RU may not be configured / defined. In addition, the multiple RUs constituting one MRU may be continuous in the frequency domain, or may not be continuous.

[0144] When an 80 MHz sub-block includes RUs of less than 996 tones or a portion of the 80 MHz sub-block is punctured, the 80 MHz sub-block may use RU allocations other than the 996-tone RUs.

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

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

[0147] New PPDU format for new operating bands

[0148] The description of the above WLAN system can be mainly applied to a WLAN system operating in an existing operating frequency band, for example, a frequency band below 7 GHz (for example, a 2.4 GHz, 5 GHz, or 6 GHz frequency band). For example, the above PPDU format can be mainly applied to a WLAN system operating in a frequency band below 7 GHz. In addition, a WLAN system operating in a high operating frequency band, for example, a millimeter wave (mmWave) frequency band such as 60 GHz has been defined.

[0149] The present disclosure describes an example of a new PPDU format (particularly, bandwidth and / or guard interval (GI) applied to the PPDU) that takes into account throughput and efficiency improvements in millimeter wave bands including (i.e., not limited to) the 60 GHz band. Here, because the scope of the present disclosure is the new PPDU format itself, there is no limitation that the examples described below must only be applied to systems operating in millimeter waves, and the examples of the present disclosure can be equally applied to other operating bands (e.g., sub-7 GHz bands).

[0150] Fig.11 is a diagram showing an example of a channelized area of ​​a millimeter wave band to which the present disclosure can be applied.

[0151] Fig.11 The example in shows the millimeter wave bands used by the United States, the European Union, South Korea, Japan, Australia, and China, and shows the size and location of the channels defined in the corresponding bands. For example, the bandwidth of each of the six channels may correspond to 2.16 GHz. In addition, when bandwidth bundling is applied, up to four unit bandwidths may be bundled to support bandwidths up to 8.64 GHz.

[0152] In addition, the bandwidths supported by a WLAN system corresponding to a 1x parameter set (e.g., a system based on IEEE 802.11ac (VHT)) 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. In addition, a tone plan for the number and position of a DC subcarrier, a guard subcarrier, a null subcarrier, a pilot subcarrier, etc. is also defined. In addition, the subcarrier spacing is defined as 312.5 kHz, the OFDM symbol length excluding the cyclic prefix (CP) length is defined as 3.2 us, and the applicable guard interval is defined as 0.8 us and 0.4 us.

[0153] As reference Figures 8 to 10As described, the bandwidths supported by a WLAN system corresponding to a 4x parameter set (e.g., a system based on IEEE 802.11ax (HE) or IEEE 802.11be (EHT)) are 20, 40, 80, 160, and 320 MHz. For bandwidths of 20, 40, 80, 160, and 320 MHz, the number of subcarriers is defined as 256, 512, 1024, 2048, and 4096, respectively. In addition, the RU / MRU tone plan for the number and position of DC subcarriers, guard subcarriers, empty subcarriers, pilot subcarriers, etc. is also defined. In addition, the subcarrier spacing is defined as 78.125 kHz, the OFDM symbol length excluding the CP length is defined as 12.8 us, and the applicable guard interval is defined as 3.2 us, 1.6 us, and 0.8 us.

[0154] Unlike existing WLAN systems, in technologies under discussion such as UHR, the use of sub-7 GHz bands (e.g., 2.4 GHz, 5 GHz, or 6 GHz bands) and / or millimeter wave bands (e.g., 60 GHz bands) is being discussed to achieve high data rates and low latency. For example, for certain use cases that require high throughput, it is difficult to meet the requirements using only the bandwidth of currently defined channels, so it may be considered to send / receive specific PPDUs through millimeter wave bands. To this end, a new PPDU format is required, especially a new design for PPDU bandwidth and guard interval.

[0155] Various examples of the present disclosure for PPDU transmission or reception based on a new PPDU format (eg, based on a new definition / operation for a guard interval) are described below.

[0156] Fig.12 is a flowchart for describing a PPDU receiving method according to the present disclosure.

[0157] In S1210 , the first STA may receive a PPDU including a first at least one field and a second at least one field.

[0158] The first at least one field may include at least one non-legacy SIG field (e.g., UHR-SIG field). For example, the first at least one field may correspond to a pre-UHR modulation field of the PPDU. For example, the first at least one field may include at least one of the following fields: a legacy STF (L-STF) field (or a non-HT STF field), a legacy LTF (L-LTF) field (or a non-HT LTF field), a legacy SIG (L-SIG) field (or a non-HT SIG field), a repeated L-SIG (RL-SIG) field (or a repeated non-HT STF field), a universal SIG (U-SIG) field, or at least one non-legacy SIG field.

[0159] The second at least one field may include a data field. For example, the second at least one field may correspond to a UHR modulation field of the PPDU. For example, the second at least one field may include at least one of a non-legacy STF field (e.g., a UHR-STF field), a non-legacy LTF field (e.g., a UHR-LTF field), or a data field.

[0160] The operating frequency band for receiving (or sending) the PPDU may be a millimeter wave band or a 60 GHz band.

[0161] In S1220, the first STA may decode the second at least one field based on the guard interval for the second at least one field, and obtain the MPDU from the data field included in the second at least one field.

[0162] The value of the guard interval for the second at least one field may be signaled / indicated through the first at least one field (e.g., at least one non-legacy SIG field included in the first at least one field) or through a separate PPDU (e.g., a PPDU transmitted / received in a different operating frequency band).

[0163] Alternatively, the value of the guard interval for the second at least one field may be predefined as a single value. Therefore, there is no need to signal / indicate the value of the guard interval for the second at least one field. For example, at least one non-legacy SIG field (e.g., U-SIG and / or UHR-SIG) of the first at least one field may lack information indicating the value of the guard interval for the second at least one field. Therefore, the signaling overhead for indicating the guard interval can be reduced, and the STA operation complexity can be reduced.

[0164] For example, the value of the guard interval for the second at least one field may be predefined as a single value. In other words, only one guard interval candidate may be defined. For example, the value of the guard interval for the second at least one field may be predefined as a single value of 0.1us. Alternatively, the value of the guard interval for the second at least one field may be predefined as a single value of 0.2us. Alternatively, the value of the guard interval for the second at least one field may be predefined as a single value of 0.4us.

[0165] The parameter set for the second at least one field may be defined based on an existing 1x parameter set or 4x parameter set and an N-fold upclocking relationship. N may correspond to a value of 4, 8, 10, etc.

[0166] For example, for a new parameter set for the second at least one field based on the 1x parameter set, the bandwidth may be defined as one of 20*N, 40*N, 80*N, or 160*N MHz; the subcarrier spacing may be 312.5*N kHz; the number of subcarriers may be one of 64, 128, 256, or 512; and the OFDM symbol length excluding the CP length may be defined as 3.2 / N us. Here, the candidate value of the guard interval may be defined as 1 / N times (e.g., 0.8 / N and 0.4 / N us) of the guard interval of the 1x parameter set or 1 / N times (e.g., 0.8 / N, 1.6 / N, and 3.2 / N us) of the guard interval of the 4x parameter set, and one of these candidate values ​​of the guard interval may be indicated / signaled. Alternatively, the guard interval may be predefined as the above-mentioned single value and may not be indicated / signaled.

[0167] For example, for a new parameter set for the second at least one field based on a 4x parameter set, the bandwidth may be defined as one of 20*N, 40*N, 80*N, 160*N, or 320*N MHz; the subcarrier spacing may be 78.125*N kHz; the number of subcarriers may be one of 256, 512, 1024, 2048, or 4096; and the OFDM symbol length excluding the CP length may be 12.8 / N us. Here, the candidate values ​​of the guard interval may be defined as 0.8 / N and 0.4 / N us, or the candidate values ​​of the guard interval may be defined as 0.8 / N, 1.6 / N, and 3.2 / N us, and one of these candidate values ​​of the guard interval may be indicated / signaled. Alternatively, the guard interval may be predefined as a single value as described above, and may not be indicated / signaled.

[0168] Fig.12 The method described in the example can be Figure 1 The first device (100) executes. For example, Figure 1 At least one processor (102) of the first device (100) may be configured to receive a PPDU and decode a data field based on a guard interval defined or signaled for a portion of a data field comprising the received PPDU. In addition, at least one memory (104) of the first device (100) may store instructions for, when executed by the at least one processor (102), performing Fig.12 or the methods described in the examples described below.

[0169] Fig.13 is a flowchart for describing a PPDU transmission method according to the present disclosure.

[0170] In S1310 , the second STA may encode the second at least one field based on the guard interval for the second at least one field.

[0171] In S1320 , the second STA may send a PPDU including the first at least one field and the second at least one field to the first STA.

[0172] Because the examples of the first at least one field, the second at least one field, and the PPDU are similar to those of the reference Fig.12 The descriptions are the same, so duplicate descriptions are omitted.

[0173] exist Fig.13 In the example, the value of the encoded guard interval applied to at least one second field (e.g., the data field) may be indicated / signaled to the first STA via the corresponding PPDU or another PPDU, or may be predefined and may not be indicated / signaled to the first STA.

[0174] Fig.13 The method described in the example can be Figure 1 The second device (200) in the embodiment executes. For example, Figure 1 At least one processor (202) of the second device (200) may be configured to send a PPDU including a data field encoded based on a guard interval. The value of the guard interval applied to the portion including the corresponding data field may be indicated / signaled to the first device receiving the PPDU, or a value known in advance by the first device, i.e., a predefined value, may be applied. In addition, at least one memory (204) of the second device (200) may store instructions for executing, when executed by the at least one processor (202), Fig.13 or the methods described in the examples described below.

[0175] Fig.12 and Fig.13 Examples of may correspond to some examples of various examples of the present disclosure. In the following, including Fig.12 and Fig.13 Various examples of the present disclosure will be described in more detail.

[0176] In the following embodiments, 60 GHz is described as a representative example of an operating frequency band to which the present disclosure is applied, but the following embodiments may also be similarly applied to another millimeter wave band other than 60 GHz or an operating frequency band other than the millimeter wave band.

[0177] In the following examples, it is described by assuming that the non-legacy PPDU format is configured with L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, non-legacy SIG, non-legacy STF, non-legacy LTF and data fields, but it is not limited to being applied only to this PPDU format. In other words, the fields in the non-legacy PPDU format as above are not exhaustively listed, and some fields may be excluded and other fields not shown may be added. The example described below may be applied to the second at least one field of the non-legacy PPDU format (e.g., at least one of the non-legacy STF, non-legacy LTF and data fields). As described above, "non-legacy" may be UHR, but is not limited by its name. Alternatively, the example described below may not be applied to the first at least one field (e.g., at least one of L-STF, L-LTF, L-SIG, RL-SIG, U-SIG and non-legacy (e.g., UHR)-SIG).

[0178] Example 1

[0179] The new parameter set and tone plan applied to the new PPDU format can be defined in the same manner as the 4x parameter set and tone plan. For example, for the second at least one field of the new PPDU format (e.g., UHR-STF / UHR-LTF / data field), the tone plan such as RU / MRU for the number and position of DC tone, guard tone, null tone and pilot tone based on 20, 40, 80, 160, 320 MHz bandwidth and 256, 512, 1024, 2048, 4096 subcarriers can be applied in the same manner.

[0180] In addition, a 480 or 640 MHz bandwidth may be defined. In this case, similar to the tone plan for 80 MHz bandwidth being repeated twice for 160 MHz bandwidth and the tone plan for 80 MHz bandwidth being repeated four times for 320 MHz bandwidth, the tone plan for 80 MHz bandwidth being repeated six times may be applied to the 480 MHz bandwidth, and the tone plan for 80 MHz bandwidth being repeated eight times may be applied to the 640 MHz bandwidth.

[0181] Example 2

[0182] New parameter sets and tone plans applied to new PPDU formats may be defined for up-converted bandwidths. Up-converted bandwidths may be used to support data rate increases and latency reductions. For example, frequency domain attributes such as bandwidth, subcarrier spacing, etc. are increased by a specific multiple (e.g., N) according to up-converting, while time domain attributes such as symbol length are reduced by a specific multiple, but the number of subcarriers in the corresponding bandwidth is the same, and the same tone plan as the existing tone plan may be applied.

[0183] Example 2-1

[0184] The upscaling based bandwidth according to this embodiment is based on the bandwidth applied to the existing 4x parameter set.

[0185] For example, for N=4, new bandwidths may be defined as 80, 160, 320, 640, 1280 MHz, which are 4 times the existing 20, 40, 80, 160, 320 MHz. In addition, a new subcarrier spacing of 312.5 kHz may be defined, which is 4 times the existing 78.125 kHz. Therefore, the number of subcarriers for 80, 160, 320, 640, and 1280 MHz bandwidths is 256, 512, 1024, 2048, and 4096, respectively. Here, the bandwidth and subcarrier spacing are increased, but the existing tone scheme may be applied in the same manner. In other words, as the tone scheme for 80, 160, 320, 640, and 1280 MHz bandwidths, the tone schemes defined for the existing 20, 40, 80, 160, and 320 MHz bandwidths may be applied, respectively. When the tone scheme is applied equally, this may mean that the number and position of data tones, DC tones, guard tones, null tones, pilot tones, etc. are applied equally.

[0186] In addition, for N=4, the OFDM symbol length becomes 1 / 4 times, so a new OFDM symbol length of 3.2us excluding the cyclic prefix (CP) can be defined. The guard interval (or CP length) can be defined as a new guard interval (or CP length) of 0.2, 0.4 or 0.8us, which is 1 / 4 times the existing 0.8, 1.6 or 3.2us. In other words, there are three candidates for the guard interval value, 0.2, 0.4 and 0.8us, and among them, one guard interval value can be applied. Alternatively, two guard intervals of 0.4 and 0.8us can be defined, as in the existing 1x parameter set. Alternatively, only one guard interval of 0.8us can be defined.

[0187] In addition, for N=4, bandwidths of 1920 and 2560 MHz may be additionally defined. For a tone plan for a 1920 MHz bandwidth, a 320 MHz bandwidth (i.e., a tone plan for a 320 MHz bandwidth based on a subcarrier spacing of 312.5 kHz and a tone plan for an 80 MHz bandwidth based on a subcarrier spacing of 78.125 kHz) may be defined to be repeated 6 times. For a tone plan for a 2560 MHz bandwidth, a 320 MHz bandwidth (i.e., a tone plan for a 320 MHz bandwidth based on a subcarrier spacing of 312.5 kHz and a tone plan for an 80 MHz bandwidth based on a subcarrier spacing of 78.125 kHz) may be defined to be repeated 8 times.

[0188] As an additional example, for N=8, bandwidths of 160, 320, 640, 1280, and 2560 MHz and a subcarrier spacing of 625 kHz may be newly defined. In other words, the number of subcarriers for bandwidths of 160, 320, 640, 1280, and 2560 MHz are 256, 512, 1024, 2048, and 4096, respectively. In addition, as tone plans for bandwidths of 160, 320, 640, 1280, and 2560 MHz, the tone plans defined for existing bandwidths of 20, 40, 80, 160, and 320 MHz may be applied, respectively. In addition, the OFDM symbol length may be newly defined as 1.6 us, excluding CP. In addition, a guard interval (or CP length may be newly defined as 0.4, 0.2, or 0.1 us. In addition, a bandwidth of 5120 MHz may be additionally defined. A tone plan in which a tone plan for a 640 MHz bandwidth based on a 625 kHz subcarrier spacing is repeated 8 times (or a tone plan in which a 2560 MHz tone plan is repeated 2 times) may be applied to a 5120 MHz bandwidth.

[0189] As an additional example, for N=10, bandwidths of 200, 400, 800, 1600, and 3200 MHz and subcarrier spacing of 781.25 kHz may be newly defined, and the tone plan may be applied in the same manner as before. In other words, as tone schemes for 200, 400, 800, 1600, and 3200 MHz bandwidths, the tone schemes defined for the existing 20, 40, 80, 160, and 320 MHz bandwidths may be applied, respectively. In addition, the OFDM symbol length may be newly defined as 1.28 us, excluding CP. In addition, the guard interval (or CP length) may be newly defined as 0.08, 0.16, or 0.32 us. In addition, bandwidths of 4800 and 6400 MHz may be additionally defined. A tone scheme in which the tone scheme for an 800 MHz bandwidth based on a 781.25 kHz subcarrier spacing is repeated 6 times may be applied to a 4800 MHz bandwidth. A tone scheme in which a tone scheme for an 800 MHz bandwidth based on a 781.25 kHz subcarrier spacing is repeated 8 times may be applied to a 6400 MHz bandwidth.

[0190] Compared to the existing 4x parameter set-based PPDU format, the bandwidth for the new PPDU format may be defined as N*20, N*40, N*80, N*160, and N*320 MHz, the subcarrier spacing may be defined as N*78.125 kHz, and the symbol length excluding the CP may be defined as 12.8 / N us. The guard interval or CP length may be defined as 0.8 / N, 1.6 / N, and 3.2 / N us (for N=4, the guard interval or CP length may be defined as 0.4 and 0.8 us or may be defined as 0.8 us). For the new PPDU format, the tone plan defined for the existing 4x parameter set-based bandwidth may be applied in the same manner. In addition, a bandwidth of N*480 MHz may be defined, and the tone plan for N*80 MHz may be repeated 6 times and applied to the bandwidth. In addition, a bandwidth of N*640 MHz may be defined, and the tone plan for N*80 MHz may be repeated 8 times and applied to the bandwidth.

[0191] Example 2-2

[0192] The upscaling based bandwidth according to this embodiment is based on the bandwidth applied to the existing 1x parameter set.

[0193] For example, for N=4, new bandwidths of 80, 160, 320, and 640 MHz may be defined for bandwidths, which are four times the existing 20, 40, 80, and 160 MHz. In addition, a new subcarrier spacing of 1.25 MHz may be newly defined for subcarrier spacing, which is four times the existing 312.5 kHz. Therefore, the number of subcarriers for 80, 160, 320, and 640 MHz bandwidths is 64, 128, 256, and 512. Here, the bandwidth and subcarrier spacing increase, but the existing tone scheme may be equally applied. In other words, as the tone scheme for 80, 160, 320, and 640 MHz bandwidths, the tone scheme defined for the existing 20, 40, 80, and 160 MHz bandwidths may be applied, respectively. When the tone scheme is equally applied, it may mean that the number and position of data tones, DC tones, guard tones, null tones, pilot tones, etc. are equally applied.

[0194] In addition, for N=4, the OFDM symbol length becomes 1 / 4 times, so a new OFDM symbol length of 0.8us excluding the cyclic prefix (CP) can be defined. The guard interval (or CP length) can be defined as a new guard interval (or CP length) of 0.2 and 0.1us, which is 1 / 4 times the existing 0.8 and 0.4us. In other words, two candidates for the guard interval value are 0.2 and 0.1us, and a guard interval value among them can be applied. Alternatively, as described below, only one guard interval can be defined.

[0195] In addition, for N=4, additional bandwidths of 1280 and 2560 MHz may be defined. The tone plan for the 1280 MHz bandwidth may be defined as two repetitions of the 640 MHz bandwidth (i.e., 1024 subcarriers). The tone plan for the 2560 MHz bandwidth may be defined as four repetitions of the 640 MHz bandwidth (i.e., 2048 subcarriers).

[0196] As an additional example, for N=8, bandwidths of 160, 320, 640, and 1280 MHz and a subcarrier spacing of 2.5 MHz may be newly defined. In other words, the number of subcarriers for bandwidths of 160, 320, 640, and 1280 MHz is 64, 128, 256, and 512. In addition, as tone plans for bandwidths of 160, 320, 640, and 1280 MHz, the tone plans defined for existing bandwidths of 20, 40, 80, 160, and 320 MHz may be applied, respectively. In addition, the OFDM symbol length may be newly defined as 0.4 us, excluding CP. In addition, the guard interval (or CP length) may be newly defined as 0.1 us or 50 ns. In addition, bandwidths of 2560 and 5120 MHz may be additionally defined. A tone plan in which the tone plan for a bandwidth of 1280 MHz is repeated 2 times (i.e., 1024 subcarriers) may be applied to a bandwidth of 2560 MHz. A tone plan in which the tone plan for 1280 MHz bandwidth is repeated 2 times (ie, 2048 subcarriers) may be applied to 5120 MHz bandwidth.

[0197] In terms of subcarrier spacing, 1x parameter set based upconversion supports wider subcarrier spacing than 4x parameter set based upconversion, so it is robust to carrier frequency offset (CFO), phase noise, etc. Considering OFDMA transmission, etc., 4x parameter set based upconversion can increase the gain in multi-user (MU) transmission. When single-user (SU) transmission in the mmWave band is prioritized and alternative methods for MU transmission (e.g., frequency division multiple access (FDMA), multi-link operation (MLO)) are considered, 1x parameter set based upconversion can be applied preferentially instead of 4x parameter set based upconversion which is expected to benefit from OFDMA transmission.

[0198] In terms of delay extension, up-conversion based on the 4x parameter set provides a wider guard interval than up-conversion based on the 1x parameter set, so it can be applied preferentially. This is for the case where only up-conversion is additionally applied to the existing PPDU transmission / reception process. If a (wider) guard interval is additionally defined for up-conversion based on the 1x parameter set, the implementation complexity may increase, but it can be used advantageously in terms of delay extension, etc.

[0199] Example 3

[0200] For new parameters applied to the new PPDU format, the guard interval may be redefined. For example, the number of candidates for the guard interval may be multiple or one.

[0201] Example 3-1

[0202] Multiple guard interval candidates may be defined for the new PPDU format. For example, for N=8, three guard interval candidates of 0.4, 0.2, and 0.1us may be defined for the case based on the 1x parameter set and the case based on the 4x parameter set. Alternatively, for N=8, two guard interval candidates of 0.2 and 0.1us may be defined for both the case based on the 1x parameter set and the case based on the 4x parameter set. When multiple guard interval candidates are defined in this manner, values ​​suitable for various delay spreads may be selectively applied.

[0203] Among a plurality of guard interval candidates, one guard interval to be applied to a specific PPDU transmission may also be indicated through a SIG field (eg, a non-legacy (eg, UHR or U)-SIG field) included in a specific PPDU.

[0204] Alternatively, among multiple guard interval candidates, a guard interval to be applied to a specific PPDU transmission may be indicated by another PPDU sent before the specific PPDU. For example, the value of the guard interval of a specific PPDU to be sent or received in a millimeter wave band may be indicated by another PPDU sent or received in a band below 7 GHz.

[0205] Example 3-2

[0206] A single guard interval value may be defined for the new PPDU format. In this case, since there is only one candidate for the guard interval value, there is no need to signal the guard interval value between the PPDU transmitting side and the PPDU receiving side, and thus overhead may be reduced. In other words, one predefined guard interval value may be applied at the transmitting side and the receiving side.

[0207] For example, for N=8, for a case based on a 1x parameter set and a case based on a 4x parameter set, a 0.4us guard interval may be predefined, or a 0.2us guard interval may be predefined, or a 0.1us guard interval may be predefined.

[0208] For example, for N=4, for a case based on a 1x parameter set and a case based on a 4x parameter set, a guard interval of 0.2 us may be predefined, or a guard interval of 0.1 us may be predefined.

[0209] Considering that most delay spreads have values ​​within 0.1 us in the mmWave band even in non-line-of-sight (NLoS) scenarios, a guard interval value of 0.1 us may be predefined for the GI in terms of throughput.

[0210] Considering the significant impact of obstacles, such as CFO, phase noise, etc., the bandwidth based on the upscaling for the bandwidth and 1x parameter set is defined, and the guard interval in this case can be defined to apply only a guard interval value of 0.1us.

[0211] Considering that for the case based on the 1x parameter set, the guard interval of 0.1us is a value derived from N=8 upscaling, if N=8 upscaling is applied, the ease of implementation can be improved in reusing the processing for existing PPDU transmission / reception.

[0212] Different from the bandwidth and guard interval applied to PPDU in the existing WLAN system, the bandwidth and / or guard interval according to the example of the present disclosure can be defined and applied based on the new parameter set considering upscaling as described above. Therefore, a new effect of effectively supporting high data rate and low delay can be achieved.

[0213] The above-mentioned embodiments are elements and features of the present disclosure combined in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be considered optional. Each element or feature can be implemented in a form that is not combined with other elements or features. In addition, the embodiments of the present disclosure may include combined partial elements and / or features. The order of the operations described in the embodiments of the present disclosure may be changed. Some elements or features of an embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. It is clear that an embodiment may include a combined claim without an explicit dependency in the claim, or may be included as a new claim by modification after application.

[0214] It is clear to those skilled in the art that the present disclosure can be implemented in other specific forms within the scope of the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted restrictively in every aspect, but should be considered as illustrative. The scope of the present invention should be determined by the reasonable interpretation of the attached claims, and all changes within the equivalent scope of the present disclosure are included in the scope of the present invention.

[0215] The scope of the present disclosure includes software or machine executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations in a device or computer according to the methods of various embodiments, and non-transitory computer-readable media that store such software or commands, etc. and can be executed in a device or computer. Commands that can be used to program a processing system that performs the features described in the present disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in the present disclosure can be implemented by using a computer program product that includes such a storage medium. The storage medium may include a high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, but is not limited thereto, and it 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 optionally includes one or more storage devices located away from the processor. The memory or alternatively, the non-volatile memory device in the memory includes a non-transitory computer-readable storage medium. The features described in this disclosure may be stored in any machine-readable medium to control the hardware of a processing system, and may be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0216] [Industrial Applicability]

[0217] The method proposed by the present disclosure is mainly described based on an example of being applied to an IEEE 802.11-based system and a 5G system, but can also be applied to various WLAN or wireless communication systems other than the IEEE 802.11-based system.

Claims

1. A method performed by a first station (STA) in a wireless local area network (WLAN) system, the method comprising: receiving, from a second STA, a physical layer protocol data unit (PPDU) including a first at least one field and a second at least one field, wherein the first at least one field includes at least one non-legacy signal (SIG) field and the second at least one field includes a data field; as well as decoding the first at least one field and the second at least one field, and obtaining a medium access control protocol data unit (MPDU) based on the data field, Therein, a guard interval for the second at least one field is predefined as a single value.

2. The method according to claim 1, wherein: The at least one non-legacy SIG field included in the first at least one field lacks information indicating a value of the guard interval for the second at least one field.

3. The method according to claim 1, wherein: The single value of the guard interval is 0.1 or 0.2 microseconds (us).

4. The method according to claim 1, wherein: For the second at least one field: 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. The Orthogonal Frequency Division Multiplexing (OFDM) symbol length excluding the Cyclic Prefix (CP) length is 3.2 / N us.

5. The method according to claim 4, wherein: N is 8 or 4.

6. The method according to claim 1, wherein: For the second at least one field: The bandwidth is one of 20*N, 40*N, 80*N, 160*N, 320*N MHz, The subcarrier spacing is 78.125*N kHz, The number of subcarriers is one of 256, 512, 1024, 2048 or 4096, The OFDM symbol length excluding the CP length is 12.8 / N us.

7. The method according to claim 6, wherein: N is 8 or 4.

8. The method according to claim 1, wherein: The second at least one field further includes at least one of a non-legacy short training field (STF) field or a non-legacy long training field (LTF) field.

9. The method according to claim 1, wherein: The first at least one field further includes at least one of a legacy STF (L-STF) field, a legacy LTF (L-LTF) field, a legacy SIG (L-SIG), a repeated L-SIG (RL-SIG) field, or a universal SIG (U-SIG) field.

10. The method of claim 1, wherein: An operating frequency band for transmitting or receiving the PPDU is a millimeter wave (mmWave) frequency band or a 60 GHz frequency band.

11. A first station (STA) device in a wireless local area network (WLAN) system, the device comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: receiving, by the at least one transceiver, from a second STA, a physical layer protocol data unit (PPDU) including a first at least one field and a second at least one field, wherein the first at least one field includes at least one non-legacy signal (SIG) field, and the second at least one field includes a data field; and decoding the first at least one field and the second at least one field, and obtaining a medium access control protocol data unit (MPDU) based on the data field, Therein, a guard interval for the second at least one field is predefined as a single value.

12. A method performed by a second station (STA) in a wireless local area network (WLAN) system, the method comprising: encoding a first at least one field comprising at least one non-legacy signal (SIG) field and a second at least one field comprising a data field, the data field comprising a medium access control protocol data unit (MPDU); as well as sending a physical layer protocol data unit (PPDU) including the first at least one field and the second at least one field to a first STA, Therein, a guard interval for the second at least one field is predefined as a single value.

13. A second station (STA) device in a wireless local area network (WLAN) system, the device comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: encoding a first at least one field comprising at least one non-legacy signal (SIG) field and a second at least one field comprising a data field, the data field comprising a media access control protocol data unit (MPDU); and sending, by the at least one transceiver, a physical layer protocol data unit (PPDU) including the first at least one field and the second at least one field to the first STA, Therein, a guard interval for the second at least one field is predefined as a single value.

14. A processing device, the processing device being configured to control a station (STA) in a wireless local area network (WLAN) system, the processing device comprising: at least one processor; as well as At least one computer memory, the at least one computer memory being operatively connected to the at least one processor and storing instructions for executing the method according to any one of claims 1 to 10 upon execution by the at least one processor.

15. At least one non-transitory computer-readable medium storing at least one instruction, wherein: The at least one instruction is executed by at least one processor to control a device to perform the method according to any one of claims 1 to 10 in a wireless local area network (WLAN) system.

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