Method and apparatus for PPDU transmission / reception in wireless LAN system

Abstract

Disclosed are a method and apparatus for PPDU transmission / reception in a wireless LAN system. A method performed by means of a first STA according to an embodiment of the present disclosure may comprise the steps of: generating a PPDU; and transmitting the PPDU to the second STA.

Description

Technical Field

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

[0002] New technologies have been introduced for wireless LANs (WLANs) 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 can be referred to as Wi-Fi. For example, recent technologies introduced to WLANs include Very High Throughput (VHT) enhancements to the 802.11ac standard and High Efficiency (HE) enhancements to the IEEE 802.11ax standard.

[0003] To provide a more complete wireless communication environment, enhancement technologies for EHT (Extreme High Throughput) are under discussion. For example, technologies are being studied to support increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, including multi-access point (AP) coordination and multiple-input, multiple-output (MIMO). In particular, various technologies are being studied to support low-latency or real-time services. Furthermore, new technologies are being discussed to support ultra-high reliability (UHR) by improving or expanding EHT technology. Summary of the Invention

[0004] Technical issues

[0005] The technical purpose of the present disclosure is to provide a method and apparatus for transmitting and receiving a plurality of PSDUs (Physical Service Data Units) for a specific receiving device.

[0006] 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.

[0007] Technical Solution

[0008] According to one aspect of the present disclosure, a method performed by a first station (STA) in a wireless local area network (WLAN) system may include generating a physical protocol data unit (PPDU) and transmitting the PPDU to a second STA. The PPDU may indicate a resource unit (RU) or multiple RUs (MRUs) to which multi-layer transmission is applied to transmit multiple physical service data units (PSDUs).

[0009] According to additional aspects of the present disclosure, a method performed by a second station (STA) in a wireless local area network (WLAN) system may include: receiving a PPDU (physical protocol data unit) from a first STA; and processing the PPDU. The PPDU may indicate a resource unit (RU) or multiple RUs (MRUs) to which multi-layer transmission is applied to transmit multiple physical service data units (PSDUs).

[0010] Beneficial effects

[0011] According to an embodiment of the present disclosure, throughput can be improved by transmitting and receiving a PPDU including a plurality of PSDUs for a specific receiving device.

[0012] In addition, by sending and receiving a PPDU containing multiple PSDUs to a specific receiving device, latency can be reduced.

[0013] Effects achievable by the present disclosure are not limited to the above-described effects, and those skilled in the art can clearly understand other effects not described herein through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 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.

[0015] Figure 1 A block configuration diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0016] Figure 2 is a diagram illustrating an exemplary structure of a WLAN system to which the present disclosure can be applied.

[0017] Figure 3 is a diagram for describing a link setting procedure to which the present disclosure can be applied.

[0018] Figure 4 is a diagram for describing a backoff process to which the present disclosure can be applied.

[0019] Figure 5 is a diagram for describing a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0020] 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.

[0021] 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.

[0022] Figure 8is a diagram illustrating an exemplary arrangement of resource units (RUs) used on a 20 MHz frequency band.

[0023] Figure 9 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on a 40 MHz frequency band.

[0024] Figure 10 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on an 80 MHz frequency band.

[0025] Figure 11 The diagram illustrates multi-layer transmission applicable to the wireless LAN system of the present disclosure.

[0026] Figure 12 The operation of the transmitting device for the PPDU transmitting and receiving method according to an embodiment of the present disclosure is illustrated.

[0027] Figure 13 The operation of the receiving device for the PPDU transmission and reception method according to an embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure may be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art will appreciate that the present disclosure may be implemented without these specific details.

[0029] 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.

[0030] In the present disclosure, when an element is referred to as being "connected," "combined," or "linked" to another element, it may include an indirect connection relationship in which another element exists therebetween as well as a direct connection relationship. In addition, in the present disclosure, the terms "comprising" or "having" specify the presence of the mentioned features, steps, operations, components, and / or elements, but do not preclude the presence or addition of one or more other features, steps, operations, components, elements, and / or groups thereof.

[0031] In the present invention, terms such as "first," "second," etc. are used only to distinguish one element from another and are not used to limit the elements. Unless otherwise specified, they do not limit the order or importance of the elements. Therefore, within the scope of the present disclosure, the first element in one embodiment may be referred to as the second element in another embodiment, and similarly, the second element in one embodiment may be referred to as the first element in another embodiment.

[0032] The terms used in this disclosure are intended to describe specific embodiments and not to limit the claims. As used in the description of the embodiments and the appended claims, the singular is intended to include the plural, unless the context clearly indicates otherwise. The term "and / or" used in this disclosure may refer to one of the relevant enumerated items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise indicated, the " / " between words in this disclosure has the same meaning as "and / or".

[0033] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to wireless LAN systems. For example, examples of the present disclosure can be applied to wireless LANs based on the IEEE 802.11a / g / n / ac / ax standards. Furthermore, examples of the present disclosure can be applied to wireless LANs based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to wireless LANs based on the IEEE 802.11be version-2 standard, which corresponds to the additional enhancements to the IEEE 802.11be version-1 standard. Furthermore, examples of the present disclosure can be applied to next-generation standard-based wireless LANs following IEEE 802.11be. Furthermore, examples of the present disclosure can be applied to cellular wireless communication systems. For example, examples of the present disclosure can be applied to cellular wireless communication systems based on Long Term Evolution (LTE) technology and 5G New Radio (NR) technology, both based on the 3rd Generation Partnership Project (3GPP) standard.

[0034] Hereinafter, technical features of examples to which the present disclosure can be applied will be described.

[0035] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0036] Figure 1 The 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. 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), or a network. It may be replaced by various terms such as an artificial intelligence (AI) system, a roadside unit (RSU), a repeater, a router, a relay, and a gateway.

[0037] Figure 1The devices 100 and 200 illustrated in FIG may be referred to as stations (STAs). For example, Figure 1 The devices 100 and 200 illustrated in FIG. 1 may be referred to by various terms such as transmitting device, receiving device, transmitting STA, and receiving STA. For example, STAs 110 and 200 may perform either an access point (AP) role or a non-AP role. That is, in this disclosure, STAs 110 and 200 may perform AP and / or non-AP functions. When STAs 110 and 200 perform AP functions, they may be referred to simply as APs, and when STAs 110 and 200 perform non-AP functions, they may be referred to simply as STAs. Furthermore, in this disclosure, an AP may also be referred to as an APSTA.

[0038] 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, IEEE 802.11 series). The first device 100 and the second device 200 can include interfaces for a media access control (MAC) layer and a physical layer (PHY) that conform to the IEEE 802.11 standard.

[0039] Furthermore, the first device 100 and the second device 200 may support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) in addition to wireless LAN technologies. Furthermore, the devices 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. Furthermore, the STAs of this 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.

[0040] The first device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein. For example, the processor 102 may generate first information / signals by processing information in the memory 104 and then transmit a wireless signal including the first information / signals via the transceiver 106. Furthermore, the processor 102 may receive a wireless signal including second information / signals via the transceiver 106 and then store information obtained through signal processing of the second information / signals in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for executing all or part of the processes controlled by the processor 102 or for executing the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein. Here, the processor 102 and memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the LTE 802.11 family). A transceiver 106 may be connected to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used in conjunction with an RF (radio frequency) unit. In this disclosure, a device may refer to a communication modem / circuit / chip.

[0041] The second device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein. For example, the processor 202 may generate third information / signals by processing information in the memory 204 and then transmit a wireless signal including the third information / signals via the transceiver 206. Furthermore, the processor 202 may receive a wireless signal including fourth information / signals via the transceiver 206 and then store information obtained through signal processing of the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for executing all or part of the processes controlled by the processor 202 or for executing the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein. 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., the IEEE 802.11 series). The transceiver 206 may be connected to the processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used in conjunction with an RF unit. In this disclosure, a device may refer to a communication modem / circuit / chip.

[0042] The hardware elements of devices 100 and 200 will be described in more detail below. Without limitation, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY and MAC). One or more processors 102 and 202 may generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) in accordance with the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information in accordance with the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this disclosure. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information in accordance with the functions, procedures, proposals, and / or methods disclosed in this disclosure, and provide them to one or more transceivers 106 and 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 this disclosure.

[0043] The one or more processors 102, 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102, 202 may be implemented using hardware, firmware, software, or a combination thereof. In some examples, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in the one or more processors 102, 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts included in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operational flowcharts included in this disclosure may be included in the one or more processors 102, 202 or may be stored in one or more memories 104, 204 and driven by the one or more processors 102, 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts included in this disclosure may be implemented in firmware or software in the form of code, commands, and / or command sets.

[0044] The one or more memories 104, 204 may be connected to the one or more processors 102, 202 and may be capable of storing data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. The one or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, a hard drive, registers, cache memory, a computer-readable storage medium, and / or a combination thereof. The one or more memories 104, 204 may be located internally and / or externally to the one or more processors 102, 202. Furthermore, the one or more memories 104, 204 may be connected to the one or more processors 102, 202 via a variety of technologies, such as wired or wireless connections.

[0045] One or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, and the like mentioned in the methods and / or operational flowcharts, etc., of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, and the like mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts, etc., included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Furthermore, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and may be configured to transmit and receive user data, control information, wireless signals / channels, and the like as described in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts, etc., included in this disclosure, via the one or more antennas 108, 208. In the present disclosure, the one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 may process the received user data, control information, wireless signals / channels, and the like by converting them from RF band signals to baseband signals using the one or more processors 102, 202. The one or more transceivers 106, 206 may convert the user data, control information, wireless signals / channels, and the like processed by the one or more processors 102, 202 from baseband signals to RF band signals. Therefore, the one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0046] 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 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 may be configured to execute the operations. For example, examples of operations for generating a transmit / receive signal or performing data processing or calculation on the transmit / receive signal in advance may include: 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signal (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / acquiring time resources or frequency resources (e.g., subcarrier resources) used for the fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / acquiring specific sequences (e.g., pilot sequences, STF / LTF sequences, additional sequences applied to SIGs) for the fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power saving operations applied to STAs; and 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding ACK signals. 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 memories 104 and 204.

[0047] Hereinafter, the downlink (DL) may refer to a link used for communication from an AP STA to a non-AP STA, and DL PPDUs / packets / signals may be transmitted and received over the DL. In DL communication, the transmitter may be part of an AP STA, and the receiver may be part of a non-AP STA. The uplink (UL) may refer to a link used for communication from a non-AP STA to an AP STA, and UL PPDUs / packets / signals may be transmitted and received over the UL. In UL communication, the transmitter may be part of a non-AP STA, and the receiver may be part of an AP STA.

[0048] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0049] The structure of a wireless LAN system can be composed of multiple components. Wireless LANs that support STA mobility transparent to upper layers can be provided through the interaction of multiple components. The basic service set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 It is exemplarily shown that two BSSs (BSS1 and BSS2) exist and two STAs are included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2 The ellipse representing the BSS in the figure can also be understood as representing the coverage area in which the STAs included in the corresponding BSS maintain communication. This area can be called a basic service area (BSA). When a STA moves out of the BSA, it cannot directly communicate with other STAs within the BSA.

[0050] If you don't consider Figure 2 If the DS is shown in Figure 1, the most basic type of BSS in a wireless LAN is the standalone BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For example, assuming other components are omitted, BSS1 consisting of only STA1 and STA2, or BSS2 consisting of only STA3 and STA4, respectively, can correspond to representative examples of an IBSS. This configuration is possible when STAs can communicate directly without an AP. Furthermore, in this type of wireless LAN, it is not configured in advance but can be configured when the LAN is needed, and this can be called an ad hoc network. Because an IBSS does not include an AP, there is no centralized management entity. In other words, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs can be mobile STAs, and access to the distributed system (DS) is not allowed, thus forming a self-contained network.

[0051] A STA's membership in a BSS can be changed dynamically by turning the STA on or off, entering or exiting a BSS region, and so on. To become a member of a BSS, a STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, a STA must associate with the BSS. This association can be established dynamically and can include the use of Distributed System Services (DSS).

[0052] 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 other cases, communication between STAs at greater distances may be required. A distributed system (DS) can be configured to support extended coverage.

[0053] DS refers to the structure of BSS interconnection. Specifically, Figure 2As shown in , a BSS can exist as an extended form of a network composed of multiple BSSs. The 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 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 logically different 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.

[0054] DS can support mobile devices by providing seamless integration of multiple BSSs and providing the logical services necessary to address the address to the destination. In addition, DS can further include a component called a portal, which serves as a bridge for the connection between the wireless LAN and other networks (e.g., IEEE 802.X).

[0055] The AP enables access to the DS through the WM for 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 through the AP. For example, Figure 2 STA2 and STA3 shown in the figure have STA functionality and provide functionality allowing associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, because all APs essentially correspond to STAs, all APs are addressable entities. The addresses used by an AP for communication on the WM and the addresses used by the AP for communication on the DSM are not necessarily the same. A BSS consisting of an AP and one or more STAs may be referred to as an infrastructure BSS.

[0056] 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.

[0057] In addition to the above-mentioned DS structure, an extended service set (ESS) can also be configured to provide wide coverage.

[0058] An ESS refers to a network of arbitrary size and complexity consisting of a DS and a BSS. An ESS can correspond to a collection of BSSs connected to a DS. However, an ESS does not include a DS. An ESS network is characterized as an IBSS in the logical link control (LLC) layer. STAs within an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs within an ESS can have the same service set identifier (SSID). The SSID is distinguished from the BSSID, which is the identifier of the BSS.

[0059] Wireless LAN systems make no assumptions about the relative physical locations of BSSs, and all of the following configurations are possible. BSSs can partially overlap, a common approach for providing continuous coverage. Furthermore, BSSs may not be physically connected, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs may be physically co-located, which can be used to provide redundancy. Furthermore, one (or more) IBSSs or ESS networks can physically exist in the same space as one (or more) ESS networks. This can be similar to the configuration corresponding to ESS networks when an ad hoc network operates in the same location as an ESS network, 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.

[0060] Figure 3 is a diagram for explaining a link setting procedure to which the present disclosure can be applied.

[0061] In order for a STA to establish a link with a network and send / receive data, it must first discover the network, authenticate, and establish an association. This process also requires an authentication process for security. The link establishment process may also be referred to as the session initiation process or the session setup process. Furthermore, the discovery, authentication, association, and security setup processes of the link establishment process are collectively referred to as the association process.

[0062] In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation by the STA. In other words, in order for the STA to access the network, it needs to find a network that it can participate in. Before participating in a wireless network, the STA should identify compatible networks. The process of identifying networks existing in a specific area is called scanning.

[0063] Scanning schemes include active scanning and passive scanning. Figure 3This diagram illustrates an exemplary network discovery operation, including an active scanning process. In active scanning, a scanning STA transmits probe request frames while moving across channels to discover nearby APs and wait for responses. A responder sends a probe response frame to the STA that sent the probe request frame. The responder can be the STA that last transmitted a beacon frame in the BSS of the scanned channel. In a BSS, the AP becomes the responder because it transmits a beacon frame. In an IBSS, STAs within the IBSS take turns transmitting beacon frames, so the responder is not constant. For example, a STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information included in the received probe response frame and then move to the next channel (e.g., channel 2) and perform scanning in the same manner (i.e., transmitting and receiving probe requests and responses on channel 2).

[0064] Although Figure 3 Although not shown, 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 through channels. A beacon frame is one of the management frames defined in IEEE 802.11 and is periodically transmitted to notify the existence of a wireless network and allow the STA performing the scan to find and participate in the wireless network. In a BSS, the AP periodically transmits beacon frames, and in an IBSS, STAs within the IBSS take turns transmitting beacon frames. When a STA performing the scan receives a beacon frame, the STA stores the BSS information 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 same manner in the next channel. Comparing active scanning and passive scanning, active scanning has the advantages of less latency and lower power consumption than passive scanning.

[0065] 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.

[0066] 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 used for authentication request / response corresponds to a management frame.

[0067] 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.

[0068] The STA can send an authentication request frame to the AP. The AP can determine whether to allow authentication of the corresponding STA based on the information included in the received authentication request frame. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0069] 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.

[0070] 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, mobility 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), mobility domain, timeout interval (e.g., association recovery time), overlapping BSS scan 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.

[0071] After the STA successfully associates with the network, a security setup procedure may be performed in step S340. The security setup procedure of step S340 may be referred to as an authentication procedure through a Robust Security Network Association (RSNA) request / response, and the authentication procedure of step S320 may be referred to as a first authentication procedure. The security setup procedure of step S340 may also be referred to simply as an authentication procedure.

[0072] 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.

[0073] Figure 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0074] In wireless LAN systems, the basic access mechanism for media access control (MAC) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism. This CSMA / CA mechanism, also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC, essentially employs a "listen before talk" access mechanism. With this type of access mechanism, the AP and / or STA performs a Clear Channel Assessment (CCA) to sense the wireless channel or medium within a predetermined time interval (e.g., the DCF Interframe Space (DIFS)) before starting transmission. If the medium is determined to be idle based on this sensing, frame transmission begins over the medium. On the other hand, if the medium is detected to be occupied or busy, the AP and / or STA does not initiate its own transmission and may set a delay period (e.g., a random backoff period) for medium intervention before attempting frame transmission. By applying a random backoff period, collisions can be minimized because multiple STAs are expected to attempt frame transmission after waiting for varying periods of time.

[0075] In addition, the IEEE 802.11 MAC protocol provides a hybrid coordination function (HCF). HCF is based on the DCF and the 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 medium access mechanism for improving the QoS (Quality of Service) of the wireless LAN, and QoS data can be transmitted in both a contention period (CP) and a contention-free period (CFP).

[0076] 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 transmit 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, ...).

[0077] When the random backoff process starts, the STA continuously monitors the medium while counting down the backoff slot according to the backoff count value determined. When it detects that the medium is occupied, it stops counting down and waits, and when the medium becomes idle, it resumes the remaining countdown.

[0078] exist Figure 4 In the example shown in Figure 2, when a packet to be transmitted arrives at STA3's MAC, STA3 can immediately transmit the frame after confirming that the medium is idle for a period of DIFS. The remaining STAs monitor and wait until the medium becomes occupied / busy. Meanwhile, STA1, STA2, and STA5 may each have data to transmit. Upon detecting that the medium is idle, each STA waits for a period of DIFS and then counts down the backoff slot according to a random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. This illustrates a case where, when STA2 completes the backoff count and begins frame transmission, STA5's remaining backoff time is less than STA1's. STA1 and STA5 temporarily stop the countdown and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and resume the backoff count. In other words, after counting down the remaining backoff slots within the remaining backoff time, frame transmission can begin. Because STA5's remaining backoff time is less than STA1's, STA5 begins frame transmission. While STA2 is occupying the medium, STA4 may also have data to send. From STA4's perspective, when the medium becomes idle, STA4 can wait DIFS and then count down according to the random backoff count value selected by STA4 and begin transmitting frames. Figure 4 The example shows a case where STA5's remaining backoff time coincides with STA4's random backoff count value. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, and data transmission fails. In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. STA1 waits while the medium is occupied by STA4 and STA5's transmissions, waits DIFS when the medium becomes idle, and then begins frame transmission after the remaining backoff time has elapsed.

[0079] like Figure 4As shown in the example, data frames are frames used to transmit data forwarded to higher layers and can be sent after a backoff after a DIFS (divided interval of time) has elapsed since the medium became idle. Management frames, on the other hand, are used to exchange management information not forwarded to higher layers and are sent after a backoff after an IFS (intermediate forwarding function) such as DIFS or Point Coordination Function (PIFS). Subtypes of management frames include beacons, association request / responses, reassociation request / responses, probe request / responses, and authentication request / responses. Control frames are frames used to control access to the medium. Subtypes of control frames include request to send (RTS), clear to send (CTS), acknowledgement (ACK), power save poll (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), null data packet announcement (NDP announcement), and triggers. If a control frame is not a response frame to a previous frame, it is sent after a backoff after a DIFS (divided interval of time) has elapsed. If it is a response frame to a previous frame, it is sent after a short IFS (SIFS) has elapsed without a backoff. The type and subtype of a frame can be identified by the type field and subtype field in the frame control (FC) field.

[0080] A Quality of Service (QoS) STA can back off after the arbitration IFS (AIFS) of the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), and then transmit the frame. Frames that can use AIFS[i] may include data frames, management frames, or control frames, excluding response frames.

[0081] Figure 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0082] As described above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which STAs directly sense the medium. Virtual carrier sensing is intended to compensate for issues that may arise in medium access, such as the hidden node problem. For virtual carrier sensing, the STA's MAC can use a network allocation vector (NAV). The NAV is a value that indicates to other STAs the remaining time until the medium is available for use by the STA currently using or authorized to use the medium. Therefore, the value set to the NAV corresponds to the period in which the medium is scheduled for use by the STA transmitting the frame, and STAs receiving the NAV value are prohibited from accessing the medium during the corresponding period. For example, the NAV can be configured based on the value of the "Duration" field in the MAC header of the frame.

[0083] exist Figure 5In the example of FIG, it is assumed that STA1 intends to send data to STA2, and STA3 is in a position to be able to eavesdrop on some or all frames sent and received between STA1 and STA2.

[0084] In order to reduce the possibility of transmission collisions 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 is performing transmission, 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 shown in FIG1 , it can be determined that the medium is idle as a result of carrier sensing by STA3 while STA2 is transmitting. In other words, STA2 may correspond to a hidden node of STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, can avoid attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0085] Specifically, STA1 can determine whether a channel is in use through carrier sensing. In physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy level or signal correlation detected in the channel. In virtual carrier sensing, STA1 can also use the Network Allocation Vector (NAV) timer to determine the channel occupancy state.

[0086] When the channel is idle for DIFS, STA1 can send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0087] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 can overhear a CTS frame from STA2, but cannot overhear an RTS frame from STA1, STA3 can use the duration information included in the CTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame). In other words, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, STA3 can set the NAV accordingly. If 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.

[0088] When STA1 receives a CTS frame from STA2, STA1 may transmit a data frame to STA2 after a SIFS interval, starting from the time when the CTS frame is received. When STA2 successfully receives the data frame, STA2 may transmit an ACK frame to STA1 after a SIFS interval as a response to the data frame. When the NAV timer expires, STA3 may determine whether the channel is currently in use through carrier sensing. If STA3 determines that the channel is not being used by other terminals during a DIFS interval after the NAV timer expires, STA3 may attempt channel access after the contention window (CW) based on random backoff has expired.

[0089] 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.

[0090] The PHY layer prepares the MAC PDU (MPDU) to be transmitted using commands or primitives (meaning a set of instructions or parameters) from the MAC layer. For example, upon receiving a command from the MAC layer requesting the PHY layer to start transmission, the PHY layer switches to transmit mode, configures the information provided by the MAC layer (e.g., data) in the form of a frame, and transmits it. Furthermore, when the PHY layer detects a valid preamble in a received frame, it monitors the preamble's header and sends a command to the MAC layer notifying the PHY layer of the start of reception.

[0091] In this manner, information transmission / reception in the wireless LAN system is performed in the form of frames, and for this purpose, a PHY layer protocol data unit (PPDU) frame format is defined.

[0092] 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) field shown in FIG may consist only of the legacy STF (L-STF), legacy LTF (L-LTF), legacy SIG (L-SIG) field, and 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.)) and the like may be included between the L-SIG field and the data field.

[0093] The STF is a signal used for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., and the LTF is a signal used for channel estimation and frequency error estimation. The STF and LTF can be referred to as signals for synchronization and channel estimation of the OFDM physical layer.

[0094] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits and may include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity field, and a 6-bit tail field. The RATE field may include information about the modulation and coding rate of the data. For example, the 12-bit length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit length field may be determined based on the PPDU type. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field may be determined as a multiple of 3. For example, for HE PPDUs, the value of the length field may be determined as a multiple of 3 + 1 or 3 + 2.

[0095] 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 to synchronize the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used by upper layers. The PPDU TAIL bit may be used to return the encoder to the 0 state. The padding bits may be used to adjust the length of the data field in predetermined units.

[0096] MAC PDU is defined according to various MAC frame formats, and the basic MAC frame consists of a MAC header, a frame body, and a frame check sequence (FCS). A MAC frame can be composed of MAC PDUs and transmitted / received through the PSDU of the data portion of the PPDU frame format.

[0097] The MAC header includes a frame control field, a duration / ID field, and an address field. The frame control field contains control information required for frame transmission and reception. The duration / ID field can be set to, for example, the time required to transmit the corresponding frame. For detailed information on the sequence control, QoS control, and HT control subfields of the MAC header, refer to the IEEE 802.11 standard.

[0098] 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 the 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 the general PPDU frame format and does not include the remaining portion (i.e., the data field).

[0099] 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.

[0100] In standards such as IEEE 802.11a / g / n / ac / ax, various types of PPDUs have been used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and data fields. The basic PPDU format may also be referred to as a non-HT PPDU format (e.g., Figure 7 (shown in (a)).

[0101] 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. Additionally, 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 the L-STF, L-LTF, and L-SIG (not shown).

[0102] 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)).

[0103] An example of the 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 (e.g. Figure 7 (d)). Depending on 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 can know whether the received PPDU is an HE PPDU or an EHT PPDU based on the presence of the RL-SIG, which will be described later.

[0104] 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, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0105] Figure 7 The EHT MU PPDU in (e) corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU can be used for both SU and MU transmissions. For example, the EHT MU PPDU can correspond to a PPDU for one or more receiving STAs.

[0106] Compared with EHT MU PPDU, Figure 7The EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for UL MU transmission (eg, a trigger frame or a trigger response schedule (TRS)) may perform UL transmission based on the EHT TB PPDU format.

[0107] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), and EHT-SIG fields may be coded and modulated so that even legacy STAs can attempt demodulation and decoding, and may be mapped based on a determined subcarrier frequency spacing (e.g., 312.5 kHz). These may be referred to as pre-EHT modulation fields. Subsequently, the EHT-STF, EHT-LTF, Data, and PE fields may be coded and modulated so that STAs that successfully decode non-legacy SIGs (e.g., U-SIG and / or EHT-SIG) and obtain the information included in these fields may be demodulated and decoded, and may be mapped based on a determined subcarrier frequency spacing (e.g., 78.125 kHz). These may be referred to as EHT modulation fields.

[0108] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields may be referred to as HE modulation fields. Furthermore, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as free VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields may be referred to as VHT modulation fields.

[0109] Figure 7 The U-SIG included in the EHT PPDU format can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol used for the U-SIG (e.g., OFDM symbol) can have a duration of 4 us, and the U-SIG can have a total duration of 8 us. Each U-SIG symbol can be used to transmit 26 bits of information. For example, each U-SIG symbol can be transmitted and received based on 52 data tones and 4 pilot tones.

[0110] The U-SIG can be constructed in 20MHz units. For example, if an 80MHz PPDU is constructed, the U-SIG may be repeated. That is, the same four U-SIGs can be included in the 80MHz PPDU. PPDUs with bandwidth exceeding 80MHz can include different U-SIGs.

[0111] For example, A uncoded bits may be transmitted via the U-SIG. The first symbol of the U-SIG (e.g., the U-SIG-1 symbol) may transmit the first X bits of information out of the total A bits of information, and the second symbol of the U-SIG (e.g., the U-SIG-2 symbol) may transmit the remaining Y bits of information out of the total A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit field). For example, the tail field may be used to terminate the trellis of the convolutional decoder and may be set to 0.

[0112] 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 FIG, (e.g., a UHR PPDU format), and in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, and some or all of the version-dependent bits may be different.

[0113] For example, the size of the version-independent bits of the U-SIG may be fixed or variable. The version-independent bits 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 bits and the version-dependent bits may be referred to by various names, such as the first control bit and the second control bit.

[0114] 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 the BSS color ID.

[0115] 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.).

[0116] The information necessary for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information about the bandwidth, information about the MCS technology applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether the DCM (Dual Carrier Modulation) technology (e.g., a technology that achieves an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and information about whether the non-legacy SIG is generated across the entire band.

[0117] Some information necessary for PPDU transmission and reception may be included in the U-SIG and / or non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information regarding the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information regarding the length of the non-legacy LTF and the CP (Cyclic Prefix) length, information regarding the GI (Guard Interval) applicable to the non-legacy LTF, information regarding preamble puncturing applicable to the PPDU, information regarding 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 information included in the U-SIG and information included in the non-legacy SIG.

[0118] Preamble puncturing may refer to the transmission of a PPDU without a signal in one or more frequency bins within the PPDU's bandwidth. For example, the size of a frequency bin (or the resolution of preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or greater.

[0119] 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 over at least one symbol, and each symbol may have a length of 4 us. Information regarding the number of symbols used for the EHT-SIG may be included in previous SIGs (e.g., HE-SIG-A, U-SIG, etc.).

[0120] 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 encoded separately.

[0121] In some cases, the common field can be omitted. For example, in compressed mode without OFDMA (Orthogonal Frequency Multiple Access), the common field can be omitted, and multiple STAs can receive the PPDU (e.g., the data field of the PPDU) on the same frequency band. In non-compressed mode with OFDMA, multiple users can receive the PPDU (e.g., the data field of the PPDU) on different frequency bands.

[0122] 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 a non-MU-MIMO allocation.

[0123] 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 (i.e., multiple receiving STAs).

[0124] A RU can include multiple subcarriers (or tones). RUs can be used when transmitting to multiple STAs based on OFDMA technology. RUs can also be defined when transmitting to a single STA. Resources can be allocated in RU units for non-legacy STF, non-legacy LTF, and data fields.

[0125] The applicable RU size can be defined based on the PPDU bandwidth. RUs can be defined identically or differently for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU placement may be different for HE PPDUs and EHT PPDUs. The applicable RU size, number of RUs and RU positions, DC subcarrier positions and number, null subcarrier positions and number, guard subcarrier positions and number, etc. for each PPDU bandwidth may be referred to as a tone plan. For example, a tone plan for high bandwidth can be defined as multiple iterations of a low bandwidth tone plan.

[0126] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2x996-tone RUs, 3x996-tone RUs, and so on. An MRU (Multiple RU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs. For example, an MRU can be defined as 52+26-tones, 106+26-tones, 484+242-tones, 996+484-tones, 996+484+242-tones, 2x996+484-tones, 3x996-tones, or 3x996+484-tones. Furthermore, the multiple RUs comprising an MRU may or may not be contiguous in the frequency domain.

[0127] The specific size of an RU can be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not restrictive and is illustrative. In addition, in this disclosure, the number of RUs within a predetermined bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) can vary depending on the RU size.

[0128] 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 can be applied to Figure 7 The PPDU format shown in FIG, and is applied based on Figure 7 A new PPDU format that excludes some fields and / or adds some fields.

[0129] Resource Units (RUs) and Resource Allocation

[0130] Figures 8 to 10 is a diagram for explaining an example of a resource unit of a wireless LAN system to which the present disclosure can be applied.

[0131] refer to Figures 8 to 10 This section describes the resource unit (RU) defined in wireless LAN systems. A RU can include multiple subcarriers (or tones). RUs are used when transmitting to multiple STAs based on OFDMA technology. RUs can also be defined when transmitting to a single STA. RUs can be used in the STF, LTF, and data fields of a PPDU.

[0132] like Figures 8 to 10As shown in FIG, RUs corresponding to different numbers of tones (i.e., subcarriers) may be used to configure some fields of a 20 MHz, 40 MHz, or 80 MHz X-PPDU (X represents HE, EHT, etc.). For example, resources may be allocated in units of RUs shown for the X-STF, X-LTF, and data fields.

[0133] Figure 8 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on a 20 MHz frequency band.

[0134] like Figure 8 As shown at the top of the figure, 26 cells (i.e., cells corresponding to 26 tones) can be allocated. Six tones can be used as a guard band in the leftmost band of the 20 MHz band, and five tones can be used as a guard band in the rightmost band of the 20 MHz band. Furthermore, seven DC tones can be inserted into the center band (i.e., the DC band), and 26 cells corresponding to 13 tones can be present to the left and right of the DC band, respectively. Furthermore, 26 cells, 52 cells, and 106 cells can be allocated to other frequency bands. Each cell can be allocated to either an STA or a user.

[0135] Figure 8 The RU layout is utilized not only in the case of multi-user (MU), but also in the case of single user (SU), in which case a 242 unit can be used, such as Figure 8 In this case, three DC tones can be inserted.

[0136] exist Figure 8 In the examples of FIG, various sizes of RUs, i.e., 26-RU, 52-RU, 106-RU, 242-RU, etc., are illustrated, but the specific sizes of these RUs can be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in the present disclosure is not limited and is exemplary. In addition, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, etc.) in the present disclosure, the number of RUs can vary depending on the RU size. Figure 9 and / or Figure 10 Example with Figure 8 The examples are the same as in that the size and / or number of RUs can be changed.

[0137] Figure 9 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on a 40 MHz frequency band.

[0138] Like Figure 8 As in the examples using various RU sizes, Figure 9Examples may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. 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.

[0139] Additionally, as illustrated, when used for a single user, 484-RU may be used.

[0140] Figure 10 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on an 80 MHz frequency band.

[0141] Like Figure 8 and Figure 9 As in the examples using various RU sizes, Figure 10 Examples may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc. In addition, in the case of 80MHz PPDU, the RU layout of HE PPDU and EHT PPDU may be different, and Figure 10 The example of FIG shows an example of RU layout for 80MHz EHT PPDU. Figure 10 In the example of , 12 tones are used as a guard band in the leftmost band of the 80 MHz band, and 11 tones are used as a guard band in the rightmost band of the 80 MHz band, which is the same for both the HE PPDU and the EHT PPDU. Unlike the HE PPDU, in which 7 DC tones are inserted in the DC band and there is a 26-RU corresponding to 13 tones on each side of the DC band, the EHT PPDU has 23 DC tones inserted in the DC band and there is a 26-RU on each side of the DC band. Unlike the HE PPDU, in which there is one null subcarrier between 242-RUs except for the center band, the EHT PPDU has five null subcarriers. In the HE PPDU, one 484-RU does not include any null subcarriers, but in the EHT PPDU, one 484-RU contains five null subcarriers.

[0142] Additionally, as illustrated, when used for a single user, 996-RU can be used, in which case it is common to insert 5 DC tones in both the HEPPDU and the EHT PPDU.

[0143] 160MHz or higher EHT PPDU can be configured with Figure 10 Multiple 80MHz sub-blocks. The RU layout for each 80MHz sub-block can be Figure 10If 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 an MRU (multiple RU), the 80 MHz sub-block can be used. Figure 10 996-RU.

[0144] Here, an MRU corresponds to a group of subcarriers (or tones) consisting of multiple RUs, and the multiple RUs that make up an MRU can be of the same or different sizes. For example, a single MRU can be defined as 52+26-tones, 106+26-tones, 484+242-tones, 996+484-tones, 996+484+242-tones, 2×996+484-tones, 3×996-tones, or 3×996+484-tones. Here, the multiple RUs that make up an MRU can correspond to small-sized RUs (e.g., 26, 52, 106) or large-sized RUs (e.g., 242, 484, 996, etc.). In other words, it may not be possible to configure / define a single MRU that includes both small-sized and large-sized RUs. In addition, the multiple RUs that make up a single MRU can be contiguous or non-contiguous in the frequency domain.

[0145] If the 80 MHz sub-block includes RUs with less than 996 tones, or the positions of the 80 MHz sub-block are punctured, the 80 MHz sub-block may use an RU arrangement that does not include a 996-tone RU.

[0146] The location of the RU may be fixed as defined in Tables 1 to 5 below, depending on the bandwidth of each PPDU.

[0147] Table 1 shows the index of RUs in a 20 MHz PPDU and the data and pilot subcarrier indexes (ranges) for each RU.

[0148] [Table 1]

[0149]

[0150] Table 2 shows the RU index within a 40 MHz PPDU and the data and pilot subcarrier index (range) for each RU.

[0151] [Table 2]

[0152]

[0153] Table 3 shows the RU index within an 80 MHz PPDU and the data and pilot subcarrier index (range) for each RU.

[0154] [Table 3]

[0155]

[0156] Table 4 shows the RU index within a 160 MHz PPDU and the data and pilot subcarrier index (range) for each RU.

[0157] [Table 4]

[0158]

[0159]

[0160] Table 5 shows the RU index within a 320 MHz PPDU and the data and pilot subcarrier index (range) for each RU.

[0161] [Table 5]

[0162]

[0163]

[0164]

[0165]

[0166] In Table 1, RU 5 corresponds to the middle 26-tone RU.

[0167] Referring to Tables 1 to 5, subcarrier index 0 corresponds to the DC tone. Negative subcarrier indices correspond to subcarriers having frequencies lower than the DC tone. Positive subcarrier indices correspond to subcarriers having frequencies higher than the DC tone. A DC subcarrier may mean a subcarrier with zero energy, including both the DC tone and the subcarrier index adjacent to subcarrier index 0 (i.e., the DC tone). A guard subcarrier may mean a subcarrier located at the edge of an OFDM symbol in the frequency domain and having zero energy. Null subcarriers are located near the DC or edge tone to prevent transmission center frequency leakage, receiver DC offset, and interference from adjacent RUs or MRUs, and have zero energy.

[0168] For each RU, an RU index may be assigned in order from low frequency to high frequency.

[0169] A PPDU in the 160 MHz or higher range can consist of multiple 80 MHz frequency sub-blocks. The tone plan and RU allocation for each 80 MHz frequency sub-block can be the same as for an 80 MHz PPDU. If the 80 MHz frequency sub-block of a 160 MHz or 320 MHz PPDU is not punctured and the entire 80 MHz frequency sub-block is used as a RU or part of an RU / MRU, the 80 MHz frequency sub-block can be used Figure 9If the 80 MHz frequency sub-block includes an RU with fewer than 996 tones or a portion of the 80 MHz frequency sub-block is punctured, the 80 MHz frequency sub-block may use Figure 9 The tone plan and RU allocation scheme excluding 996-tone RUs is shown in FIG.

[0170] Multiple RUs (MRUs) may be allocated to a STA. The subcarrier index of the MRU may consist of the indexes of the corresponding RUs constituting the MRU.

[0171] Here, an MRU corresponds to a group of subcarriers (or tones) consisting of multiple RUs, and the multiple RUs that make up the MRU can be of the same or different sizes. For example, a single MRU can be defined as 52+26-tones, 106+26-tones, 484+242-tones, 996+484-tones, 996+484+242-tones, 2×996+484-tones, 3×996-tones, or 3×996+484-tones. Here, the multiple RUs that make up an MRU can correspond to small-sized RUs (e.g., 26, 52, 106) or large-sized RUs (e.g., 242, 484, 996, etc.). In other words, it may not be possible to configure / define a single MRU that includes both small and large RUs. Furthermore, the multiple RUs that make up a single MRU may or may not be contiguous in the frequency domain.

[0172] An RU that is equal to or greater than a 242-tone RU is defined as a large-size RU, and an RU that is smaller than the 242-tone RU can be defined as a small-size RU.

[0173] A small size RU can only be combined with a small size RU to form a small size MRU.The small size MRU defined for DL ​​and UL OFDMA transmission can be defined as follows: 52+26-tone MRU and 106+26-tone MRU.

[0174] A large RU can only be combined with another large RU to form a large MRU. The large MRU defined for DL ​​and UL OFDMA transmission can be defined as follows: 484+242-tone MRU, 996+484-tone MRU, 996+484+242-tone MRU, 2x996+484-tone MRU, 3x996-tone MRU, and 3x996+484-tone MRU. The large MRU defined for DL ​​and UL OFDMA transmission can be defined as follows: 484+242-tone MRU, 996+484-tone MRU, 2x996+484-tone MRU, 3x996-tone MRU, and 3x996+484-tone MRU.

[0175] The RUs disclosed herein can be used for uplink (UL) and / or downlink (DL) communications. For example, when performing trigger-based UL-MU communication, the STA (e.g., the AP) transmitting the trigger can allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the second STA using trigger information (e.g., a trigger frame or TRS (Trigger Response Schedule)). Thereafter, the first STA can transmit a first trigger-based (TB) PPDU based on the first RU, and the second STA can transmit a second TB PPDU based on the second RU. The first and second TB PPDUs can be transmitted to the AP within the same time interval.

[0176] For example, when a DL MU PPDU is configured, the STA (eg, AP) transmitting the DL MU PPDU may allocate a first RU (eg, 26 / 52 / 106 / 242-RU, etc.) to a first STA and a second RU (eg, 26 / 52 / 106 / 242-RU, etc.) to a second STA.

[0177] Hereinafter, the U-SIG included in the EHT PPDU will be described in more detail.

[0178] For a 40MHz EHT PPDU or ER (Extended Range) preamble, the U-SIG content is the same across both 20MHz sub-channels. For an 80MHz EHT PPDU or ER preamble, the U-SIG content is the same across all non-punctured 20MHz sub-channels. For a 160 / 320MHz EHT PPDU or ER preamble, the U-SIG content is the same across all non-punctured 20MHz sub-channels within each 80MHz sub-block and may differ from the U-SIG content in other 80MHz sub-blocks.

[0179] The U-SIG-1 portion of the U-SIG of the EHT MU PPDU may include a PHY version identifier (B0-B2), BW (B3-B5), UL / DL (B6), BSS color (B7-B12), and TXOP (B13-B19), and the U-SIG-2 portion may include a PPDU type and compression mode (B0-B1), verification (B2), punctured channel information (B3-B7), verification (B8), EHT-SIG MCS (B9-B10), the number of EHT-SIG symbols (B11-B15), CRC (B16-B19), and trailer (B20-B25).

[0180] Here, an example of a 5-bit punctured channel indication for a non-OFDMA case in an EHT MU PPDU is shown in Table 6 below.

[0181] [Table 6]

[0182]

[0183]

[0184]

[0185]

[0186] In the puncture patterns in Table 6, 1 represents a non-punctured subchannel and x represents a punctured subchannel. The puncture granularity for 80 MHz and 160 MHz PPDU bandwidths may be 20 MHz, and the puncture granularity for 320 MHz PPDU bandwidth may be 40 MHz.

[0187] Next, the U-SIG-1 part of the U-SIG of the EHT TB PPDU may include a version identifier (B0-B2), BW (B3-B5), UL / DL (B6), BSS color (B7-B12), TXOP (B13-B19), and ignore (B20-B25), and the U-SIG-2 part may include a PPDU type and compression mode (B0-B1), verification (B2), spatial reuse 1 (B3-B6), spatial reuse 2 (B7-B10), ignore (B11-B15), CRC (B16-B19), and trailer (B20-B25).

[0188] As described above, the U-SIG field of the EHT MU PPDU includes 5 bits of punctured channel information, but the EHT TB PPDU does not include punctured channel information. This is because the EHT TB PPDU is assumed to be configured based on resource allocation indicated by the trigger frame or TRS (Triggered Response Scheduling) control information, so the STA does not need to notify the AP of the EHT TB PPDU's resource information.

[0189] Furthermore, even if a STA receives a trigger frame or TRS control information as described above, the STA may not respond with a HE TBPPDU. For example, if one or more subfields of the Common Information field or the User field addressed to or selected by a non-AP STA included in the trigger frame are not recognized, supported, or have values ​​that the non-AP STA does not satisfy, the non-AP STA may choose not to respond to the trigger frame. Similarly, if the TRS Control subfield included in a frame addressed to a non-AP STA is not recognized, supported, or has a value that the non-AP STA does not satisfy, the non-AP STA may choose not to respond to the TRS Control subfield.

[0190] The EHT-SIG included in the EHT PPDU will be described in more detail below.

[0191] The EHT-SIG field of a 20 MHz EHT MU PPDU includes one EHT-SIG content channel. For OFDMA and non-OFDMA transmission for multi-user, the EHT-SIG field of a 40 MHz or 80 MHz EHT MU PPDU includes two EHT-SIG content channels. For OFDMA and non-OFDMA transmission for multi-user, the EHT-SIG field of a 160 MHz or higher EHT MU PPDU includes two EHT-SIG content channels for each 80 MHz frequency sub-block. When the bandwidth of the EHT MU PPDU for OFDMA transmission is greater than 80 MHz, the EHT-SIG content channel for each 80 MHz frequency sub-block may carry different information.

[0192] Each EHT-SIG content channel may consist of a common field and a user-specific field, wherein the common field may include one or two RU allocation subfields depending on the PPDU frequency bandwidth.

[0193] For OFDMA transmission, the common field of the EHT-SIG content channel may include information for RU allocation, such as the RU allocation to be used in the EHT modulation field of the PPDU, the RUs allocated to MU-MIMO, the number of users in the MU-MIMO allocation, etc. When the bandwidth is 20 / 30 / 80 MHz, the common field may consist of one common coding block, and the common coding block may include one or two RU allocation-A subfields. When the bandwidth is 160 MHz, the common field may consist of two common coding blocks, and the first common coding block may include two RU allocation-A subfields, and the second common coding block may include two RU allocation-B subfields. When the bandwidth is 320 MHz, the common field may consist of two common coding blocks, and the first common coding block may include two RU allocation-A subfields, and the second common coding block may include six RU allocation-B subfields.

[0194] In non-OFDMA transmission, the common field of the EHT-SIG content channel may not include the RU allocation subfield.

[0195] The RU Allocation-A subfield for each EHT-SIG content channel corresponding to a 20 MHz frequency subchannel may indicate the RU or MRU allocation, including the RU / MRU size and their arrangement in the frequency domain. The RU Allocation-A subfield may also indicate the information necessary to calculate the number of users allocated to each RU / MRU.

[0196] The Each RU Allocation-B subfield of the EHT-SIG content channel corresponding to the 20 MHz frequency subchannel can indicate the RU or MRU allocation, including the size of the RU / MRU and their arrangement in the frequency domain. The Each RU Allocation-B subfield can also indicate the information necessary to calculate the number of users allocated to each RU / MRU.

[0197] Both the RU allocation-A subfield and the RU allocation-B subfield may be referred to as RU allocation subfields located in different common coding blocks.

[0198] For OFDMA transmissions wider than 80 MHz, the RU Allocation subfield for each 80 MHz frequency sub-block may convey consistent RU or MRU size and arrangement information for the entire PPDU.

[0199] Table 7 illustrates mapping from the 9-bit RU allocation subfield to the RU allocation and the number of user fields per RU or MRU associated with the user specific field within the same EHT SIG content channel.

[0200] [Table 7]

[0201]

[0202]

[0203]

[0204]

[0205]

[0206] Referring to Table 7, for RU Allocation subfields with a value greater than 64, y2y1y0 = 000-111 indicates the number of user fields within the EHT-SIG content channel that include the corresponding 9-bit RU Allocation subfield. The binary vector y2y1y0 indicates the N number of user fields within the EHT-SIG content channel that include the corresponding 9-bit RU Allocation subfield. user (r,c)=2 2 ×y2 + 2 1 × y1 + y0 + 1 user fields.

[0207] In Table 7, the Number of Entries column may indicate the number of RU Allocation subfield values ​​that refer to the same RU allocation used in the frequency domain. However, due to different RU Allocation subfield values, different number of user fields may be included in the user-specific field of the same EHT-SIG content channel as the RU Allocation subfield.

[0208] If the RU Allocation subfield in Table 7 has a value designated as Ignore, the STA may skip the N user (r,c) user fields and continue processing the EHT-SIG field.

[0209] Table 8 illustrates the RU or MRU associated with each RU allocation subfield for each EHT-SIG content channel and PPDU bandwidth.

[0210] [Table 8]

[0211]

[0212]

[0213] Multi-layer transmission

[0214] Multi-layer transmission is an unequal error protection (UEP) approach that provides different robustness to different services at the physical (PHY) layer.

[0215] In multi-layer transmission, the base layer (e.g., I-frames (Intra-frames)) is better protected at lower rates, while the enhancement layers (e.g., P-frames (Predicted frames) and B-frames (Bidirectional frames)) are better protected at higher rates.

[0216] Multi-layer transmission can achieve a good balance between data rate and robustness, while further reducing transmission delay.

[0217] Figure 11 The diagram illustrates multi-layer transmission in a wireless LAN system applicable to the present disclosure.

[0218] like Figure 11 As shown in , one method of implementing UEP is to use different modulation and coding schemes (MCS) for different frames of different PPDUs (e.g., different time resources allocated in the time domain). For example, a PPDU carrying control information, a PPDU carrying an I frame, a PPDU carrying a P / B frame, and a PPDU carrying other frames can be sent on different PHY resources. Here, different PHY resources not only refer to different time resources in the time domain, but also refer to different spatial streams (SS) in the spatial domain, different resource units (RU) in the frequency domain, and different constellation points in the constellation domain.

[0219] That is, PPDUs sent to different physical resources carry different frames, and different frames can have different QAM (quadrature amplitude modulation), different coding rates, different numbers of spatial streams (NSS), and different retransmission times (ReTx times).

[0220] Another method is to enable multiple PSDUs (Physical Layer Service Data Units) to be included in a single PPDU, each PSDU having a different MCS, etc. That is, as described above, the multiple PSDUs included in a single PPDU can have different QAMs applied, different coding rates, different numbers of spatial streams (NSS), different numbers of retransmissions (ReTx times), etc.

[0221] Multi-layer transmission based on selective gain can be very useful in interference environments, a major problem facing current WLAN systems. For example, if there is strong interference within a single RU, an error in that RU may not cause errors in other RUs.

[0222] Resource allocation method in multi-layer transmission

[0223] In a WLAN system (802.11), a scenario where multiple PSDUs are transmitted to a single STA using a single PPDU can be considered. In this case, the above-described multi-layer transmission can be applied.

[0224] More specifically, various types of data can be transmitted to a single STA, and depending on the characteristics of each data type, an appropriate MCS, number of spatial streams, coding scheme, and so on can be applied to the transmission. This scenario can correspond to a situation where multiple PSDUs are transmitted to a single STA. While time domain duplexing (TDD) can be used to sequentially transmit a PPDU carrying each PSDU in the time domain, this can result in increased PPDU overhead. Therefore, the aforementioned multi-layer transmission method can be considered, in which multiple PSDUs are transmitted within a single PPDU.

[0225] The present disclosure proposes a method for allocating one or more RUs / MRUs in a multi-layer transmission scenario (ie, a scenario in which multiple PSDUs are transmitted to a single STA via a single PPDU).

[0226] Hereinafter, for ease of explanation, the present disclosure assumes a scenario in which a single RU or MRU is allocated to support multi-layer transmission. However, the method proposed in the present disclosure can be extended and applied even when multiple RUs or MRUs are allocated for multi-layer transmission.

[0227] The method for allocating RUs or MRUs for multi-layer transmission can be the same as the 802.11be method described above. For example, if the PPDU for multi-layer transmission corresponds to non-OFDMA transmission, the MRU used for PPDU transmission can be specified using a puncture indication (see Table 6). Alternatively, if the PPDU for multi-layer transmission corresponds to OFDMA transmission, the MRU used for PPDU transmission can be specified using the RU Allocation subfield (see Tables 7 and 8).

[0228] Hereinafter, in the description of the present disclosure, for the sake of convenience of explanation, a method of using the RU allocation subfield (i.e., the RU allocation subfield defined in the x-SIG field (e.g., the UHR SIG field), which is defined to be the same as the RU allocation subfield defined in the EHT-SIG field) in OFDMA transmission is mainly described, but the present disclosure is not limited thereto, and the method proposed in the present disclosure can also be applied to non-OFDMA transmission.

[0229] In other words, for example, the method proposed in the present disclosure can be applied in OFDMA transmission between an STA to which an RU / MRU for multi-layer transmission is allocated and other STAs to which an RU / MRU for general transmission is allocated, and further, the method proposed in the present disclosure can be applied in MU transmission between an STA to which an RU / MRU for multi-layer transmission is allocated and other STAs to which an RU / MRU for general transmission is allocated, and further, the method proposed in the present disclosure can be applied in SU transmission only through an STA to which an RU / MRU for multi-layer transmission is allocated.

[0230] The RU / MRU that can be allocated for multi-layer transmission may be as follows:

[0231] 52+26-tone RU / MRU / 106+26-tone RU / MRU / 484+242-tone RU / MRU / 996+484-tone RU / MRU / 996+484+242-tone RU / MRU / 2x996-tone RU / MRU / 2x996+484-tone RU / MRU / 3x996-tone RU / MRU / 3x996+484-tone RU / MRU / 4x996-tone RU / MRU

[0232] The above RU / MRU examples are independent of the ascending or descending order of the frequencies of the RUs that make up the RU / MRU. That is, in the above RU / MRU examples, the RUs that make up the RU / MRU can be combined in any order. For example, in the above example, the 52+26-tone RU / MRU can be a combination of: i) a 52-tone RU and ii) a 25-tone RU with a higher frequency than the 52-tone RU; or i) a 52-tone RU and ii) a 25-tone RU with a lower frequency than the 52-tone RU.

[0233] As described above, by indicating a predefined value in the RU allocation subfield (i.e., the RU allocation subfield defined in the x-SIG field (e.g., UHR SIG field), which is identically / equivalently defined as the RU allocation subfield defined in the EHT-SIG field), the RU / MRU illustrated above can be allocated to the STA performing multi-layer transmission.

[0234] In this case, multi-layer transmission may be additionally indicated. In addition, information indicating that a specific RU / MRU is subject to multi-layer transmission may be indicated.

[0235] Here, if the user field within the x-SIG field (e.g., the UHR SIG field) indicates additional multi-layer transmission, the additional information for multi-layer transmission (in addition to the transmission information used for each PSDU transmission and the RU / MRU format, etc.) may require more bits than when transmitting information used for general transmission, which may increase the size of the corresponding user field. Furthermore, to eliminate STA decoding errors and save power, it may be preferable to uniformly match the number of bits. However, if the indication of multi-layer transmission is included in the user field, overhead issues may arise. Furthermore, if the number of bits in the user field is configured differently depending on the transmission method (i.e., multi-layer transmission or general transmission) as described above, the boundaries between the user fields for each user may be inconsistent, causing the STA to have to decode all user fields.

[0236] Therefore, in order to reduce overhead and achieve energy saving for STAs, information indicating that multi-layer transmission is applied to a specific RU / MRU can be indicated in a common field (i.e., a field carrying common information about the user) within the x-SIG field (e.g., UHR SIG field).

[0237] To this end, information for designating / identifying a RU / MRU for multi-layer transmission can be explicitly indicated within a common field within an x-SIG field (eg, UHR SIG field).

[0238] In addition, the reserved (or ignored) value of the RU Allocation subfield in the x-SIG field (e.g., the UHR SIG field) can be utilized. That is, by indicating a specific RU / MRU using a value other than those defined for RU / MRU allocation for general transmission in the RU Allocation subfield (i.e., an unused value), the RU / MRU can be implicitly indicated as a RU / MRU for multi-layer transmission.

[0239] All STAs can decode the common field (i.e., within the x-SIG field (e.g., within the UHR SIG field)) to determine (i.e., based on explicit or implicit indication) that a specific user field (i.e., within the x-SIG field (e.g., within the UHR SIG field)) corresponds to the RU / MRU for multi-layer transmission. Therefore, the number of bits in all user fields, including the user field corresponding to the RU / MRU for multi-layer transmission, can be identified.

[0240] As described above, if a special RU / MRU is explicitly or implicitly indicated as a RU / MRU for multi-layer transmission, information about all PSDUs for multi-layer transmission may be included in one user field corresponding to the RU / MRU for multi-layer transmission (i.e., in the x-SIG field (e.g., in the UHR SIG field)). For example, for all PSDUs, MCS information applicable to each PSDU (e.g., modulation scheme (BPSK (binary phase shift keying), QPSK (quadrature phase shift keying), 16-QAM, 64-QAM, 256-QAM, 1024-QAM, 4096 QAM, etc.) and coding rate (1 / 2, 3 / 4, 2 / 3, 3 / 4, 5 / 6, etc.)), NSS information (e.g., the number of spatial streams), and coding information (e.g., whether BCC (binary convolutional coding) or LDPC (low-density parity check) is used) may be included in the user field.

[0241] A method in which RU / MRU for multi-layer transmission is implicitly indicated is described in more detail below.

[0242] Table 9 illustrates the ignore value for the RU allocation subfield within the EHT SIG field. Table 9 corresponds to a portion of Table 7 and can be explained with reference to Table 7.

[0243] [Table 9]

[0244]

[0245] Referring to Table 7 and Table 9, the RU Allocation subfield within the EHT-SIG field consists of 9 bits (B0-B9), and values ​​304 to 511 are defined as ignored.

[0246] In Tables 7 and 9, y2y1y0 = 000-111 indicates the number of user fields including the corresponding 9-bit RU allocation subfield within the EHT-SIG content channel. The binary vector y2y1y0 indicates the number of user fields including the corresponding 9-bit RU allocation subfield within the EHT-SIG content channel. user (r,c)=2 2 × y2 + 2 1 × y1 + y0 + 1 user fields.

[0247] As described above, the RU Allocation subfield (i.e., the RU Allocation subfield defined in the x-SIG field (e.g., the UHR SIG field), which is identically defined as the RU Allocation subfield defined in the EHT-SIG field) can be used to allocate RUs / MRUs for multi-layer transmission. In this case, one or more of the values ​​304 to 511 as illustrated in Tables 7 and 9 can be used.

[0248] Here, a large-size RU / MRU (e.g., an MRU including RUs equal to or greater than a 242-tone RU) is generally capable of MU MIMO transmission, but multi-layer transmission may be limited to a single STA transmission. That is, multi-layer transmission may be limited to SU transmission. Therefore, the number of entries in the RU allocation subfield indicating a specific RU / MRU for multi-layer transmission may be limited to one entry, instead of eight. In other words, the RU / MRU allocated for multi-layer transmission may be allocated to only one STA. For example, a specific value in the RU allocation subfield (i.e., one of the values ​​304 to 511) may be limited to a single value. In other words, the aforementioned y2y1y0 may be set / defined as a single specific value and may not be used for a range of specified values, such as 000-111.

[0249] In addition, there may be various configurations depending on the combination of RUs in a large-size RU / MRU of a specific size. In this case, the value of the RU allocation subfield may be assigned depending on the configuration of each combination.

[0250] For example, in the existing method, referring to Table 7, a 996+484-tone MRU composed of a 996-tone RU and a 484-tone RU can be defined as four 996+484-tone MRUs depending on the positions of the 996-tone RU and the 484-tone RU. In this case, each 996+484-tone MRU is indicated by the RU allocation subfield value 128-135, 136-143, 144-151, or 152-159 in Table 7.

[0251] Here, to minimize the reserved value (i.e., the ignored value) used in the RU Allocation subfield, the larger RU / MRU formed by combining consecutive RUs in the frequency domain can be limited to achieve multi-layer transmission. For example, a large RU / MRU capable of multi-layer transmission may have RUs that are combined consecutively at least within a specific channel (e.g., an 80 MHz or 160 MHz channel). If a large RU / MRU formed by combining non-contiguous RUs is used, the RU / MRU or channel may not be allocated or punctured in the intervals between non-contiguous RUs.

[0252] Small-sized MRUs (eg, MRUs consisting only of RUs smaller than a 242-tone RU) may not be used for multi-layer transport due to their inherent small size, which may reduce their usability.

[0253] As described above, if a small-sized MRU is used for multi-layer transmission, the RU / MRU allocated for multi-layer transmission can only be allocated to a single STA. Here, if a small-sized MRU is used for multi-layer transmission, only the 106+26-tone MRU in the small-sized MRU can be used for multi-layer transmission.

[0254] If a specific small-sized MRU is used for multi-layer transmission, various scenarios can be considered depending on the location of the MRU and the combination of other RUs / MRUs within the 20 MHz range. Therefore, indicating this in the RU Allocation subfield may require a number of reserved values ​​(i.e., ignored values). Therefore, various constraints can be considered to minimize this situation.

[0255] Here, the small-size MRUs used for multi-layer transmission can be limited to those located on the left or right side of the 20 MHz. In other words, the small-size MRUs used for multi-layer transmission within a single 20 MHz can be predetermined as small-size MRUs located in specific locations. For example, for a 52+26-tone MRU, only 52-tone RU 2 + 26-tone RU 2 can be used for multi-layer transmission, or only 52-tone RU 3 + 26-tone RU 8 can be used for multi-layer transmission. As another example, for a 106+26-tone MRU, only 106-tone RU 1 + 26-tone RU 5 can be used for multi-layer transmission, or only 106-tone RU 2 + 26-tone RU 5 can be used for multi-layer transmission.

[0256] Furthermore, the scenario of applying multi-layer transmission to two (or more) MRUs within a 20 MHz channel can be eliminated. In other words, multi-layer transmission can be applied to only one MRU within a 20 MHz channel. For example, in the case of a 52+26-tone MRU, only one of 52-tone RU 2+26-tone RU 2, 52-tone RU 2+26-tone RU 5, and 52-tone RU 3+26-tone RU 8 can be used for multi-layer transmission. As another example, in the case of a 106+26-tone MRU, only one of 106-tone RU 1+26-tone RU 5 and 106-tone RU 2+26-tone RU 5 can be used for multi-layer transmission. However, multi-layer transmission is not applicable to two (or more) MRUs within a single PPDU, and the position of the MRU to which multi-layer transmission is applied may not be fixed.

[0257] Additionally, within a 20 MHz channel transmitting multiple layers, the number of RUs / MRUs used may be limited (e.g., i) up to 4 when 52+26 MRUs are applied in multiple layers, or ii) up to 3 when 106+26 MRUs are applied in multiple layers), and / or the number of RUs / MRUs of a specific size may be limited (e.g., i) up to 2 26-tone RUs when 52+26 MRUs are applied in multiple layers, or ii) 26-tone RUs are unavailable (i.e., 0 available) when 106+26 MRUs are applied in multiple layers. In other words, within a 20 MHz channel applying multiple layers, the number of RUs / MRUs allocated to other STAs may be limited, or the number of RUs / MRUs of a specific size may be limited.

[0258] Figure 12 The operation of the transmitting device for the PPDU transmitting and receiving method according to an embodiment of the present disclosure is illustrated.

[0259] Figure 12 The diagram illustrates the operation of the transmitting device based on the previously proposed method. Figure 12 The examples are provided for convenience of explanation only and do not limit the scope of the present disclosure. Figure 12 Some of the steps illustrated in FIG. 5 may be omitted depending on the situation and / or setup.

[0260] refer to Figure 12 , the sending device generates a PPDU ( S1201 ).

[0261] Here, the transmitting device of the PPDU may be an AP or a non-AP STA, and the receiving device of the PPDU may be an AP or a non-AP STA. For the convenience of the following description, the transmitting device may be referred to as a first STA, and the receiving device may be referred to as a second STA.

[0262] Here, the PPDU can consist of a legacy part, a SIG part (eg, U-SIG, UHR-SIG, etc.), an STF part (eg, UHR-STF), an LTF part (eg, UHR-LTF), and a data part.

[0263] All or part of any part (i.e., field) can be divided into multiple subparts / subfields. Each field (and its subfields) can be transmitted in units of 4us * N (where N is an integer). In addition, a guard interval (GI) can be included. A common subcarrier frequency spacing value (delta_f = 312.5 kHz / N or 312.5 kHz * N, where N is an integer) can be applied to all fields, or a first delta_f can be applied to the first part (e.g., all legacy parts, all / part of the SIG part), and a second delta_f (e.g., a value smaller than the first delta_f) can be applied to all / part of the remaining parts.

[0264] Some of the above fields can be omitted, and the order of the fields can be changed in various ways. For example, the subfields of the signal part can be placed before the STF part, and the remaining subfields of the SIG part can be placed after the STF part.

[0265] The legacy part may include at least one of a conventional non-HT short training field (L-STF), a non-HT long training field (L-LTF), and a non-HT signal field (L-SIG).

[0266] The SIG part (e.g., including the U-SIG field, the UHR-SIG field, etc.) may include various control information for the transmitted PPDU, such as the STF part, the LTF part, and control information for data decoding.

[0267] The above-mentioned STF part may include an STF sequence.

[0268] The LTF part may include a training field (ie, an LTF sequence) for channel estimation.

[0269] The data portion may include packets and user data for a higher layer. Here, the data portion transmitted on the corresponding RU or MRU may include a plurality of PSDUs transmitted using a multi-layer transmission method.

[0270] The transmitting device may configure / generate a PPDU based on the acquired control information. The step of configuring / generating the PPDU may include configuring / generating each field of the PPDU. That is, step S1201 may include constructing one or more fields containing control information regarding the tone plan. For example, step S1201 may include constructing a signal field (x-SIG field) containing control information regarding the tone plan. That is, it may include constructing a field containing control information indicating the size / position of the RU (e.g., an N-bitmap) and / or a field containing an identifier of the STA receiving the RU (e.g., an AID).

[0271] In addition, step S1201 may include generating an STF / LTF sequence to be sent via a specific RU. The STF / LTF sequence may be generated based on a preset STF generation sequence / LTF generation sequence.

[0272] Additionally, step S1201 may include generating a data field to be transmitted through a specific RU (ie, a data field transmitted on a RU or MRU for multi-layer transmission includes a plurality of PSDUs).

[0273] According to an embodiment of the present disclosure, an RU or an MRU to which multi-layer transmission is applied to transmit a plurality of physical service data units (PSDUs) may be indicated through a PPDU.

[0274] For example, the RU or MRU to which multi-layer transmission is applied may be indicated by a common field within the PPDU. Here, the common field refers to a field including common information for all users and, for example, may be included in a signal field (x-SIG field) within the PPDU.

[0275] In addition, according to an embodiment of the present disclosure, a PPDU can be used for OFDMA transmission or non-OFDMA transmission (i.e., MU transmission or SU transmission). When the PPDU is used for OFDMA transmission, the RU / MRU to which multi-layer transmission is applied can be allocated to a specific STA among the RU / MRUs allocated to multiple STAs. In this case, multiple PSDUs can be included in the data field transmitted on the RU / MRU for multi-layer transmission. When the PPDU is used for non-OFDMA transmission (i.e., MU transmission or SU transmission), the RU / MRU to which multi-layer transmission is applied can be allocated to a specific STA. In this case, multiple PSDUs can be included in the data field transmitted on the RU / MRU for multi-layer transmission.

[0276] Based on the PPDU used for OFDMA transmission, the RU or MRU to which multi-layer transmission is applied may be indicated through the RU allocation subfield within the common field within the PPDU.

[0277] Here, a value other than the value used in the RU Allocation subfield for PPDU transmission to which multi-layer transmission is not applied may be used to indicate the RU or MRU to which multi-layer transmission is applied. For example, the ignore value illustrated in Table 9 may be used to indicate the RU or MRU for multi-layer transmission.

[0278] In addition, the RU or MRU to which multi-layer transmission is applied can be allocated only to a single STA. As described above, when the ignore value illustrated in Table 9 is used, the value indicating the RU or MRU for multi-layer transmission can include only a single entry.

[0279] Furthermore, an MRU consisting only of a combination of consecutive RUs in the frequency domain can be used as an MRU to which multi-layer transmission is applied.

[0280] Furthermore, an MRU composed only of RUs smaller than a certain size (eg, an MRU composed only of RUs smaller than a 242-tone RU) may not be used as an MRU to which multi-layer transmission is applied.

[0281] In addition, the position of the RU or MRU to which multi-layer transmission is applied within a subchannel (eg, a 20 MHz subchannel) for the PPDU may be predetermined.

[0282] In addition, the number of RUs or MRUs to which multi-layer transmission is applied within a subchannel (eg, a 20 MHz subchannel) for a PPDU may be limited to only one.

[0283] In addition, if the subchannel used for the PPDU includes RUs or MRUs to which multi-layer transmission is applied, i) the number of RUs or MRUs used in the subchannel can be limited to a predetermined number, or ii) the number of RUs or MRUs of a specific size used in the subchannel can be limited to a predetermined number.

[0284] The transmitting device (ie, the first STA) transmits a PPDU to the receiving device (ie, the second STA) ( S1202 ).

[0285] Here, for the S1202 operation, the transmitting device (ie, the first STA) may perform at least one of cyclic shift diversity (CSD), spatial mapping, inverse discrete Fourier transform (IDFT) / inverse fast Fourier transform (IFFT) operations, and guard interval (GI) insertion operations.

[0286] Figure 12 The method described in the example can be used by Figure 1 The first device (100) performs. For example, Figure 1 The one or more processors (102) of the first device (100) may be configured to generate a PPDU and transmit the PPDU via the transceiver (106). In addition, the one or more memories (104) of the first device (100) may store instructions for executing the instructions when executed by the one or more processors (202). Figure 12 or commands for the methods described in the examples above.

[0287] Figure 13 The operation of the receiving device for the PPDU transmission and reception method according to an embodiment of the present disclosure is illustrated.

[0288] Figure 13 The operation of the receiving device based on the previously proposed method is illustrated. Figure 13The examples in FIG. 5 are provided for the convenience of explanation and do not limit the scope of the present disclosure. Figure 13 Some of the steps illustrated in FIG. 5 may be omitted depending on the situation and / or setup.

[0289] refer to Figure 13 , a receiving device receives a PPDU including a plurality of PSDUs ( S1301 ).

[0290] Here, the transmitting device of the PPDU can be an AP or a non-AP STA, and the receiving device of the PPDU can be an AP or a non-AP STA. For the convenience of the following description, the transmitting device can be referred to as a first STA, and the receiving device can be referred to as a second STA.

[0291] Here, the PPDU can consist of a legacy part, a SIG part (eg, U-SIG, UHR-SIG, etc.), an STF part (eg, UHR-STF), an LTF part (eg, UHR-LTF), and a data part.

[0292] All or part of any part (i.e., field) can be divided into multiple subparts / subfields. Each field (and its subfields) can be transmitted in units of 4us * N (where N is an integer). In addition, a guard interval (GI) can be included. A common subcarrier frequency spacing value (delta_f = 312.5 kHz / N or 312.5 kHz * N, where N is an integer) can be applied to all fields, or a first delta_f can be applied to the first part (e.g., all legacy parts, all / part of the SIG part), and a second delta_f (e.g., a value smaller than the first delta_f) can be applied to all / part of the remaining parts.

[0293] Some of the above fields can be omitted, and the order of the fields can be changed in various ways. For example, the subfields of the signal part can be placed before the STF part, and the remaining subfields of the SIG part can be placed after the STF part.

[0294] The legacy part may include at least one of a conventional non-HT short training field (L-STF), a non-HT long training field (L-LTF), and a non-HT signal field (L-SIG).

[0295] The SIG part (e.g., including the U-SIG field, the UHR-SIG field, etc.) may include various control information for the transmitted PPDU, such as the STF part, the LTF part, and control information for data decoding.

[0296] The above-mentioned STF part may include an STF sequence.

[0297] The LTF part may include a training field (ie, an LTF sequence) for channel estimation.

[0298] The data portion may include packets for a higher layer and user data. Here, a plurality of PSDUs transmitted in a multi-layer transmission manner may be included in the data portion transmitted on the corresponding RU or MRU.

[0299] Here, the receiving device (i.e., the second STA) can receive all or part of the PPDU through step S1301. Here, for the operation of step S1301, the receiving device (i.e., the second STA) can perform an operation to recover the results of the CSD, spatial mapping, IDFT / IFFT operation, and GI insertion operation applied by the transmitting device (for example, applied in the above-mentioned step S1202).

[0300] The receiving device (ie, the second STA) processes the PPDU ( S1302 ).

[0301] Here, the receiving device (ie, the second STA) may be able to decode all / part of the PPDU. In addition, the receiving device (ie, the second STA) may be able to obtain control information related to the tone plan (ie, RU) from the decoded PPDU.

[0302] More specifically, the receiving device can decode the x-SIG field of the PPDU based on the legacy STF / LTF and obtain the information contained in the x-SIG field. For example, information about various tone plans (i.e., RUs) can be included in the x-SIG field, and the receiving STA can obtain the information about the tone plans (i.e., RUs) through the x-SIG field. Information about various tone plans (i.e., RUs) can be included in the x-SIG, and the receiving STA can obtain the information about the tone plans (i.e., RUs) through the x-SIG.

[0303] The receiving device (i.e., the second STA) can decode the remainder of the PPDU based on the acquired tone schedule (i.e., RU) information. For example, the receiving device (i.e., the second STA) can decode the STF / LTF fields of the PPDU based on the tone schedule (i.e., RU) information. Furthermore, the receiving device (i.e., the second STA) can decode the data field of the PPDU based on the tone schedule (i.e., RU) information and obtain the MPDU contained in the data field (i.e., the data field transmitted on the RU or MRU for multi-layer transmission includes multiple PSDUs).

[0304] In addition, the receiving device (i.e., the second STA) can perform processing operations to forward the decoded data (i.e., including multiple PSDUs) to a higher layer (e.g., a MAC layer). In addition, if the higher layer instructs the PHY layer to generate a signal in response to the data forwarded to the higher layer, the receiving device can perform subsequent operations.

[0305] According to an embodiment of the present disclosure, a RU or MRU to which multi-layer transmission is applied to transmit a plurality of physical service data units (PSDUs) may be indicated through the PPDU.

[0306] For example, the RU or MRU to which multi-layer transmission is applied may be indicated by a common field within the PPDU. Here, the common field refers to a field including common information for all users, and may be included, for example, within a signal field (x-SIG field) within the PPDU.

[0307] In addition, according to embodiments of the present disclosure, a PPDU can be used for OFDMA transmission or non-OFDMA transmission (i.e., MU transmission or SU transmission). When a PPDU is used for OFDMA transmission, the RU / MRU to which multi-layer transmission is applied can be allocated to a specific STA among the RU / MRUs allocated to multiple STAs. In this case, multiple PSDUs can be included in the data field transmitted on the RU / MRU used for multi-layer transmission. When a PPDU is used for non-OFDMA transmission (i.e., MU transmission or SU transmission), the RU / MRU to which multi-layer transmission is applied can be allocated to a specific STA. In this case, multiple PSDUs can be included in the data field transmitted on the RU / MRU used for multi-layer transmission.

[0308] Based on the PPDU used for OFDMA transmission, the RU or MRU to which multi-layer transmission is applied may be indicated through the RU allocation subfield within the common field within the PPDU.

[0309] Here, a value other than the value used in the RU Allocation subfield for PPDU transmission to which multi-layer transmission is not applied may be used to indicate the RU or MRU to which multi-layer transmission is applied. For example, the ignore value illustrated in Table 9 may be used to indicate the RU or MRU for multi-layer transmission.

[0310] In addition, the RU or MRU to which multi-layer transmission is applied can be allocated only to a single STA. As described above, when the ignore value illustrated in Table 9 is used, the value indicating the RU or MRU for multi-layer transmission can include only a single entry.

[0311] Furthermore, an MRU consisting only of a combination of consecutive RUs in the frequency domain can be used as an MRU to which multi-layer transmission is applied.

[0312] Furthermore, an MRU composed only of RUs smaller than a certain size (eg, an MRU composed only of RUs smaller than a 242-tone RU) may not be used as an MRU to which multi-layer transmission is applied.

[0313] In addition, the position of the RU or MRU to which multi-layer transmission is applied within a subchannel (eg, a 20 MHz subchannel) for the PPDU may be predetermined.

[0314] In addition, the number of RUs or MRUs to which multi-layer transmission is applied within a subchannel (eg, a 20 MHz subchannel) for a PPDU may be limited to only one.

[0315] In addition, if the subchannel used for the PPDU includes RUs or MRUs to which multi-layer transmission is applied, i) the number of RUs or MRUs used in the subchannel can be limited to a predetermined number, or ii) the number of RUs or MRUs of a specific size used in the subchannel can be limited to a predetermined number.

[0316] Figure 13 The method described in the example can be used by Figure 1 The second device (200) executes. For example, Figure 1 The one or more processors (202) of the second device (200) may be configured to receive and process the PPDU via the transceiver (206). In addition, the one or more memories (204) of the second device (200) may store instructions for executing the instructions when executed by the one or more processors (202). Figure 13 or commands for the methods described in the examples above.

[0317] In conventional wireless LAN systems, a PPDU sent to a single STA is configured to include only a single PSDU. However, according to examples of the present disclosure, the data field sent on the RU / MRU assigned to a specific STA within the PPDU can be configured to include multiple PSDUs. Therefore, by supporting multi-layer transmission to a specific STA using a PPDU including RUs / MRUs carrying multiple PSDUs, throughput can be improved and latency can be reduced, thereby enhancing wireless communication efficiency.

[0318] 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 not combined with other elements or features. In addition, the embodiments of the present disclosure may include combined 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 with corresponding elements or features of other embodiments. It is clear that an embodiment may include a combined claim without an explicit dependency relationship in the claim, or may be included as a new claim by modification after application.

[0319] It is clear to those skilled in the art that the present disclosure can be implemented in other specific forms without exceeding 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 appended claims, and all changes within the equivalent range of the present disclosure are included within the scope of the present invention.

[0320] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that perform operations in accordance with the methods of various embodiments in a device or computer, as well as non-transitory computer-readable media that store such software or instructions and are executable in the device or computer. Commands that can be used to program a processing system to perform the features described in this disclosure can be stored in a storage medium or computer-readable storage medium, and the features described in this disclosure can be implemented using a computer program product that includes such a storage medium. The storage medium can include, but is not limited to, high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, and can also 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 can optionally include one or more storage devices located remotely from the processor. The memory, or alternatively, the non-volatile memory device in the memory, comprises a non-transitory computer-readable storage medium. The features described in this disclosure may be stored in any machine-readable medium to control the hardware of a processing system and may be integrated into software and / or firmware that allows the processing system to utilize the results from embodiments of the present disclosure and interact with other mechanisms. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0321] Industrial Applicability

[0322] 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: Generate PPDU (Physical Protocol Data Unit); as well as sending the PPDU to a second station, The PPDU indicates a resource unit (RU) or multiple RUs (MRUs) to which multi-layer transmission is applied to transmit a plurality of physical service data units (PSDUs).

2. The method according to claim 1, wherein The RU or the MRU to which the multi-layer transmission is applied is indicated by a common field within the PPDU.

3. The method according to claim 1, wherein Based on the PPDU being used for Orthogonal Frequency Division Multiple Access (OFDMA) transmission, the RU or the MRU to which the multi-layer transmission is applied is indicated by a RU allocation subfield within a common field within the PPDU.

4. The method according to claim 3, wherein: The RU or MRU to which multi-layer transmission is applied is indicated using a value other than a value used in the RU allocation subfield for PPDU transmission to which multi-layer transmission is not applied.

5. The method according to claim 3, wherein The RU or the MRU to which multi-layer transmission is applied is allocated only to a single STA.

6. The method according to claim 3, wherein: An MRU including only a combination of consecutive RUs in the frequency domain may be used as an MRU to which multi-layer transmission is applied.

7. The method according to claim 3, wherein: An MRU composed of a combination of RUs smaller than a specific size cannot be used as an MRU to which multi-layer transmission is applied.

8. The method according to claim 3, wherein: The position of the RU or the MRU to which the multi-layer transmission is applied, which is available in a subchannel for the PPDU, is predetermined.

9. The method according to claim 3, wherein: The number of RUs or MRUs to which the multi-layer transmission is applied in a subchannel for the PPDU is limited to one.

10. The method according to claim 3, wherein: Based on the RU or the MRU to which the multi-layer transmission is applied being included in the subchannel used for the PPDU, i) the number of RUs or MRUs used in the subchannel is limited to a predetermined number, or ii) the number of RUs or MRUs of a specific size used within the subchannel is limited to a predetermined number.

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: Generate PPDU (Physical Protocol Data Unit); and Sending the PPDU to a second STA, The PPDU indicates a resource unit (RU) or multiple RUs (MRUs) to which multi-layer transmission is applied to transmit a plurality of physical service data units (PSDUs).

12. A method performed by a second station (STA) in a wireless local area network (WLAN) system, the method comprising: Receive PPDU (Physical Protocol Data Unit) from the first STA; as well as processing the PPDU, The PPDU indicates a resource unit (RU) or multiple RUs (MRUs) to which multi-layer transmission is applied to transmit a plurality of physical service data units (PSDUs).

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: Receive a PPDU (Physical Protocol Data Unit) from a first STA; and processing the PPDU, The PPDU indicates a resource unit (RU) or multiple RUs (MRUs) to which multi-layer transmission is applied to transmit a plurality of physical service data units (PSDUs).

14. A processing device configured to control a station (STA) in a wireless local area network (WLAN) system, the processing device comprising: at least one processor; as well as At least one computer memory, the at least one computer memory being operatively connected to the at least one processor and storing instructions for performing 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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