Method and apparatus for transmitting or receiving relay frame in wireless LAN system

Abstract

Disclosed are a method and an apparatus for transmitting or receiving a relay frame in a wireless LAN system. According to an embodiment of the present disclosure, a method performed by a first station (STA) in a wireless LAN system may comprise the steps of: receiving, from an access point (AP), a request frame related to initiation of a relay operation targeting one or more second STAs; sending a response frame for the request frame to the AP; receiving, from the AP, a PPDU including data based on the relay operation; and transmitting the PPDU including the data to the one or more second STAs. The request frame may include ID information for identifying the one or more second STAs as destinations of the relay operation.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for transmitting and receiving relay frames in a wireless local area network (WLAN) system. Background Art

[0002] New technologies for increasing transmission rate, increasing bandwidth, increasing reliability, reducing errors, and reducing latency have been introduced for wireless local area network (WLAN). Among WLAN technologies, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series standards can be referred to as Wi-Fi. For example, technologies recently introduced into WLAN include very high throughput (VHT) enhancements of the 802.11ac standard and high efficiency (HE) enhancements of the IEEE 802.11ax standard.

[0003] To provide a more advanced wireless communication environment, improved technologies for extremely high throughput (EHT) are being discussed. For example, technologies for multiple-input multiple-output (MIMO) and multi-access point (AP) coordination that support increased bandwidth, efficient use of multiple bands, and increased spatial streams are being studied, and specifically, various technologies for supporting low latency or real-time services are being studied. In addition, new technologies for supporting ultra-high reliability (UHR), including improvements or extensions of EHT technologies, are being discussed. Summary of the Invention

[0004] Technical Problem

[0005] A technical object of the present disclosure is to provide a method and apparatus for transmitting and receiving relay frames in a wireless local area network (WLAN) system.

[0006] A technical object of the present disclosure is to provide a method and apparatus for transmitting and receiving relay frames through a relay station (STA) controlled by an AP in a wireless LAN system.

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

[0008] Technical Solution

[0009] According to an aspect of the present disclosure, a method performed by a first station (STA) in a wireless LAN system may include: receiving, from an access point (AP), a request frame related to initiation of a relay operation targeting one or more second STAs; transmitting, to the AP, a response frame to the request frame; receiving, from the AP, a physical layer protocol data unit (PPDU) including data based on the relay operation; and transmitting, to one or more second STAs, a PPDU including the data. Here, the request frame may include ID information for identifying one or more second STAs as destinations of the relay operation.

[0010] According to another aspect of the present disclosure, a method performed by an AP in a wireless LAN system may include: sending a request frame related to the initiation of a relay operation targeting one or more second STAs to a first STA; receiving a response frame for the request frame from the first STA; and sending a physical layer protocol data unit (PPDU) including data based on the relay operation to the first STA. Here, the request frame may include ID information for identifying one or more second STAs as destinations of the relay operation.

[0011] Technical effects

[0012] According to the present disclosure, a method and apparatus for transmitting and receiving relay frames in a wireless local area network (WLAN) system can be provided.

[0013] According to the present disclosure, a method and apparatus for transmitting and receiving relay frames through a relay STA controlled by an AP in a wireless LAN system can be provided.

[0014] According to the present disclosure, by using a relay method to perform signal transmission to an STA, the influence of distance and obstacles can be reduced, and the reception quality (e.g., received SNR) of the STA can be improved, thereby providing technical effects of reducing the latency of signal transmission and increasing the throughput.

[0015] The effects that can be achieved by the present disclosure are not limited to the above effects, and those skilled in the relevant art can clearly understand other effects not described herein through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings included as part of the specific embodiments for understanding the present disclosure provide embodiments of the present disclosure and describe the technical features of the present disclosure together with the specific embodiments.

[0017] Figure 1 Illustrates a configuration block diagram of a wireless communication device according to an embodiment of the present disclosure.

[0018] Figure 2 Is a diagram illustrating an exemplary structure of a WLAN system to which the present disclosure can be applied.

[0019] Figure 3 Is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0020] Figure 4 Is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0021] Figure 5 Is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0022] Figure 6 is a diagram for illustrating an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0023] Figure 7 is a diagram for exemplifying an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0024] Referring to Figure 8 , a relay STA may correspond to a non-AP STA that performs relay transmission controlled by an AP.

[0025] Figure 9 exemplifies an example of a relay transmission process according to an embodiment of the present disclosure.

[0026] Figure 10 exemplifies another example of a relay transmission process according to an embodiment of the present disclosure.

[0027] Figure 11 exemplifies a format of a relay frame applicable to an embodiment of the present disclosure.

[0028] Figure 12 exemplifies a flowchart of operations performed by a first STA according to an embodiment of the present disclosure.

[0029] Figure 13 exemplifies a flowchart of operations performed by an AP according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description to be disclosed through the drawings is to describe exemplary embodiments of the present disclosure, and does not represent the only embodiments in which the present disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art know that the present disclosure can be implemented without these specific details.

[0031] In some cases, known structures and devices may be omitted, or may be shown in the form of block diagrams based on the core functions of each structure and device in order to prevent ambiguity of the concept of the present disclosure.

[0032] 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 as well as a direct connection relationship in which another element exists therebetween. Further, in the present disclosure, the term "comprising" or "having" specifies the presence of the mentioned features, steps, operations, components, and / or elements, but does not exclude the presence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0033] In the present disclosure, terms such as "first", "second", etc. are only used to distinguish one element from another and do not limit the element, unless otherwise specified, and do not limit the order or importance between elements, etc. Therefore, within the scope of the present disclosure, the first element in an embodiment can be referred to as the second element in another embodiment, and similarly, the second element in an embodiment can be referred to as the first element in another embodiment.

[0034] The terms used in the present disclosure are for the purpose of describing specific embodiments and do not limit the claims. As used in the description of the embodiments and the appended claims, the singular forms are intended to include the plural forms unless the context clearly indicates otherwise. The term "and / or" used in the present disclosure can refer to one of the related listed items or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise specified, the " / " between words in the present disclosure has the same meaning as "and / or".

[0035] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to a wireless LAN system. For example, examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to a wireless LAN based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11be version 2 standard corresponding to additional enhancement technologies of the IEEE 802.11be version 1 standard. Additionally, examples of the present disclosure can be applied to a wireless LAN based on the next-generation standard after IEEE 802.11be. Furthermore, examples of the present disclosure can be applied to a cellular wireless communication system. For example, it can be applied to a cellular wireless communication system based on the long-term evolution (LTE) technology and the 5G new radio (NR) technology based on the 3rd Generation Partnership Project (3GPP) standards.

[0036] Hereinafter, the technical features to which the examples of the present disclosure can be applied will be described.

[0037] Figure 1 The block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0038] Figure 1The first device 100 and the second device 200 illustrated in the example can be replaced with various terms such as a terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSU), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user. Additionally, the first device 100 and the second device 200 include an access point (AP), a base station (BS), a fixed station, a Node B, a base transceiver system (BTS), a network. It can be replaced with various terms such as an artificial intelligence (AI) system, a roadside unit (RSU), a repeater, a router, a relay, and a gateway.

[0039] Figure 1 The devices 100 and 200 illustrated in the example can be referred to as a station (STA). For example, Figure 1 The devices 100 and 200 illustrated in the example can be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, STAs 110 and 200 can perform an access point (AP) role or a non-AP role. That is, in the present disclosure, STAs 110 and 200 can perform AP and / or non-AP functions. When STAs 110 and 200 perform the AP function, they can be simply referred to as APs, and when STAs 110 and 200 perform the non-AP function, they can be simply referred to as STAs. Additionally, in the present disclosure, an AP can also be indicated as an AP STA.

[0040] Referring to Figure 1 , the first device 100 and the second device 200 can transmit and receive radio signals through various wireless LAN technologies (e.g., the 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) compliant with the IEEE 802.11 standard.

[0041] Additionally, in addition to wireless LAN technologies, the first device 100 and the second device 200 can additionally support various communication standard (e.g., 3GPP LTE series, 5G NR series standards, etc.) technologies. Additionally, the devices of the present disclosure can be implemented in various devices such as a mobile phone, a vehicle, a personal computer, an augmented reality (AR) device, and a virtual reality (VR) device. Additionally, the STAs in this specification can support various communication services such as a voice call, a video call, data communication, autonomous driving, machine type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), Internet of Things (IoT), etc.

[0042] The first device 100 may include one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, after generating first information / signals by processing information in the memory 104, the processor 102 may transmit a wireless signal including the first information / signals via the transceiver 106. Additionally, the processor 102 may receive a wireless signal including second information / signals via the transceiver 106, and then store the information obtained by 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 performing all or part of the processing controlled by the processor 102 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used with an RF (radio frequency) unit. In the present disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0043] The second device 200 may include one or more processors 202 and one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, the processor 202 may generate third information / signals by processing the information in the memory 204, and then transmit wireless signals including the third information / signals through the transceiver 206. Additionally, the processor 202 may receive wireless signals including fourth information / signals through the transceiver 206, and then store the information obtained by 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 codes including instructions for performing all or part of the processing controlled by the processor 202 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technologies (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 through one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used with an RF unit. In the present disclosure, a device may mean a communication modem / circuit / chip.

[0044] Hereinafter, the hardware components of apparatuses 100 and 200 will be described in more detail. Without being limited thereto, 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) according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (e.g., baseband signals) from one or more transceivers 106 and 206 according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure, and obtain PDUs, SDUs, messages, control information, data, or information.

[0045] One or more processors 102 and 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by 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, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be included in one or more processors 102 and 202, or may be stored in one or more memories 104 and 204 and driven by one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by using firmware or software in the form of codes, instructions, and / or instruction sets.

[0046] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, code, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard disk drives, registers, cache memories, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located inside and / or outside one or more processors 102, 202. Additionally, one or more memories 104, 204 may be connected to one or more processors 102, 202 through various techniques such as wired or wireless connections.

[0047] One or more transceivers 106, 206 may send user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operation flowcharts, etc. of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation 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 send and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to send user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to send and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts, etc. included in the present disclosure via one or more antennas 108, 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert the received wireless signals / channels, etc. from RF band signals into baseband signals to process the received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 may convert the user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals into RF band signals. Thus, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0048] For example, one of STAs 100 and 200 may perform the expected operations of an AP, and the other of STAs 100 and 200 may perform the expected operations of a non-AP STA. For example, Figure 1 the transceivers 106 and 206 may perform the sending and receiving operations of signals (e.g., packets or physical layer protocol data units (PPDUs) compliant with IEEE 802.11a / b / g / n / ac / ax / be / bn). Additionally, in the present disclosure, the operations of various STAs to generate transmit / receive signals or to perform data processing or calculations on the transmit / receive signals in advance may be performed by Figure 1The processors 102 and 202 execute. For example, examples of operations for generating transmission / reception signals or performing data processing or calculations on transmission / reception signals in advance may include: 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (such as signals (SIG), short training fields (STF), long training fields (LTF), data, etc.) included in a PPDU; 2) determining / configuring / acquiring time resources or frequency resources (such as subcarrier resources) for fields (SIG, STF, LTF, data, etc.) included in a PPDU; 3) determining / configuring / acquiring specific sequences (such as pilot sequences, STF / LTF sequences, additional sequences applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in PPDU operations; 4) power control operations and / or power saving operations applied to an STA; 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding, etc. of ACK signals. Additionally, in the following examples, various information (such as information related to fields / sub-fields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals may be stored in Figure 1 the memories 104 and 204.

[0049] Hereinafter, a downlink (DL) may refer to a link for communication from an AP STA to a non-AP STA, and DL PPDUs / packets / signals may be transmitted and received through the DL. In DL communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. An uplink (UL) may refer to a link for communication from a non-AP STA to an AP STA, and UL PPDUs / packets / signals may be transmitted and received through the UL. In UL communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

[0050] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure may be applied.

[0051] The structure of a wireless LAN system may be composed of multiple components. A wireless LAN that supports STA mobility transparent to the upper layer may be provided through the interaction of multiple components. A basic service set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 Exemplarily, it is shown that there are two BSSs (BSS1 and BSS2), and two STAs included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2The ellipse representing the BSS can also be understood as representing the coverage area in which the STAs included in the corresponding BSS maintain communication. This area can be referred to as the Basic Service Area (BSA). When an STA moves outside the BSA, it cannot communicate directly with other STAs within the BSA.

[0052] If the DS shown in Figure 2 is not considered, the most basic BSS type in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimal form that only includes two STAs. For example, assuming other components are omitted, BSS1 that only includes STA1 and STA2 or BSS2 that only includes STA3 and STA4 can respectively correspond to representative examples of an IBSS. This configuration is possible when STAs can communicate directly without an AP. Additionally, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs can be composed of mobile STAs and are not allowed to access the Distributed System (DS), thus forming a self-contained network.

[0053] The membership of STAs in a BSS can be dynamically changed by turning STAs on or off, entering or exiting the BSS area, etc. To become a member of a BSS, an STA can use synchronization processing to join the BSS. To access all services of the BSS infrastructure, an STA should be associated with the BSS. This association can be dynamically established and can include using the Distribution System Service (DSS).

[0054] The direct STA-to-STA distance in a wireless LAN may be limited by PHY performance. In some cases, this distance limitation may be sufficient, but in some cases, communication between STAs at longer distances may be required. The Distributed System (DS) can be configured to support extended coverage.

[0055] DS means the structure for interconnecting BSSs. Specifically, as Figure 2As shown, the 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 different purposes and is used by different components. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of the wireless LAN structure (DS structure or other network structures) can be interpreted as multiple media being logically different. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be independently specified by the physical characteristics of each implementation.

[0056] The DS can support mobile devices by providing seamless integration of multiple BSSs and providing the logical services necessary for addressing the addresses to the destination. In addition, the DS can also include a component called a portal, which is used as a bridge for the connection between the wireless LAN and other networks (e.g., IEEE 802.X).

[0057] The AP enables access to the DS through the WM for the associated non-AP STA and refers to an entity that also has the STA function. The data movement between the BSS and the DS can be performed by the AP. For example, Figure 2 STA2 and STA3 shown in have the functions of the STA and provide the functions that allow the associated non-AP STAs (STA1 and STA4) to access the DS. In addition, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM is not necessarily the same as the address used by the AP for communication on the DSM. The BSS composed of an AP and one or more STAs can be called an infrastructure BSS.

[0058] Data sent from one of the STAs associated with the AP to the STA address of the corresponding AP can always be received at the uncontrolled port and can be processed by the IEEE 802.1X port access entity. In addition, when the controlled port is authenticated, the transmitted data (or frame) can be delivered to the DS.

[0059] In addition to the above DS structure, the extended service set (ESS) can also be configured to provide wide coverage.

[0060] An ESS means a network composed of a DS and BSSs with an arbitrary size and complexity. An ESS can correspond to a set of BSSs connected to a DS. However, an ESS does not include the DS. The ESS network is characterized by an IBSS in the logical link control (LLC) layer. STAs included in an ESS can communicate with each other, and a mobile STA can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in an ESS can have the same service set identifier (SSID). The SSID is distinguished from the BSSID which is an identifier of a BSS.

[0061] The wireless LAN system does not assume anything about the relative physical positions of BSSs, and all of the following forms are possible. BSSs can partially overlap, which is a form commonly used to provide continuous coverage. Additionally, BSSs can be not physically connected, and logically, there is no limit on the distance between BSSs. Additionally, BSSs can be physically located at the same position, which can be used to provide redundancy. Additionally, one (or more than one) IBSS or ESS network can physically exist in the same space as one (or more than one) ESS network. This can correspond to forms of an ESS network when an ad-hoc network operates at a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required at the same position.

[0062] Figure 3 is a diagram for explaining the link establishment process to which the present disclosure can be applied.

[0063] In order for an STA to establish a link with respect to a network and send / receive data, it first discovers the network, performs authentication, establishes an association, and needs to perform an authentication process for security. The link establishment process can also be referred to as a session initiation process or a session establishment process. Additionally, the processes of discovery, authentication, association, and security establishment in the link establishment process can be collectively referred to as an association process.

[0064] In step S310, the STA can perform a network discovery operation. The network discovery operation can include a scanning operation of the STA. That is, in order for the STA to access the network, it needs to find a network it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying networks existing in a specific area is called scanning.

[0065] Scanning schemes include active scanning and passive scanning. Figure 3A network discovery operation including an active scanning process is exemplarily illustrated. In active scanning, the STA performing the scanning sends a probe request frame to discover which APs exist around it while moving across channels and waits for a response thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that has sent the probe request frame. Here, the responder can be the STA that last sent a beacon frame in the BSS of the channel being scanned. In a BSS, since the AP sends a beacon frame, the AP becomes the responder, and in an IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, the STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information included in the received probe response frame, and can move to the next channel (e.g., channel 2), and perform scanning in the same way (i.e., send and receive probe requests / responses on channel 2).

[0066] Although not shown in Figure 3 it, the scanning operation can be performed in a passive scanning manner. In passive scanning, the STA performing the scanning waits for beacon frames while moving across channels. A beacon frame is one of the management frames defined in IEEE 802.11 and is periodically sent to notify the existence of a wireless network and to allow the STA performing the scanning to find the wireless network and participate in the wireless network. In a BSS, the AP is used to periodically send beacon frames, and in an IBSS, the STAs within the IBSS rotate to send beacon frames. When the STA performing the scanning receives a beacon frame, the STA stores the information of the BSS included in the beacon frame, and while moving to another channel, records the beacon frame information in each channel. The STA that receives a beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel in the same way. Comparing active scanning with passive scanning, the advantage of active scanning is that it has less latency and less power consumption than passive scanning.

[0067] After the STA discovers the network, the authentication process can be performed in step S320. To clearly distinguish it from the security establishment operation in step S340 to be described later, this authentication process can be called the first authentication process.

[0068] The authentication process includes the following process: The STA sends an authentication request frame to the AP, and in response thereto, the AP sends an authentication response frame to the STA. The authentication frames for authentication request / response correspond to management frames.

[0069] The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), a finite cyclic group, etc. This corresponds to some examples of information that can be included in the authentication request / response frame, and can be replaced with other information, or additional information can also be included.

[0070] The STA can send an authentication request frame to the AP. The AP can determine whether to allow the 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.

[0071] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the following processes: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0072] For example, the association request frame can include information related to various capabilities, a beacon listening interval, a Service Set Identifier (SSID), supported rates, supported channels, RSN, a mobility domain, supported operation classes, a Traffic Indication Map Broadcast Request (TIM broadcast request), interoperable service capabilities, etc. For example, the association response frame can include information related to various capabilities, a status code, an Association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal-to-Noise Ratio Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association recovery time), overlapping BSS scan parameters, a TIM broadcast response, Quality of Service (QoS) mapping, etc. This corresponds to some examples of information that can be included in the association request / response frame, and can be replaced with other information, or additional information can also be included.

[0073] After the STA is successfully associated with the network, the security establishment process can be performed in step S340. The security establishment process in step S340 can be referred to as an authentication process through a Robust Security Network Association (RSNA) request / response. The authentication process in step S320 is referred to as the first authentication process, and the security establishment process in step S340 can also simply be referred to as an authentication process.

[0074] The security establishment process in step S340 can, for example, include a process of establishing a private key using the Extensible Authentication Protocol over LAN (EAPOL) frame through a four-way handshake. Additionally, the security establishment process can be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0075] Figure 4 It is a diagram for illustrating the backoff process to which the present disclosure can be applied.

[0076] In a wireless LAN system, the basic access mechanism of the Media Access Control (MAC) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also referred to as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC and basically adopts the "listen before talk" access mechanism. According to this type of access mechanism, before starting to transmit, the AP and / or STA can perform a Clear Channel Assessment (CCA) of sensing the radio channel or medium during a predetermined time interval (e.g., the DCF Interframe Space (DIFS)). As a result of the sensing, if it is determined that the medium is idle, frame transmission is started through the corresponding medium. On the other hand, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not start its own transmission and can set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after waiting. By applying the random backoff period, since it is expected that multiple STAs will attempt frame transmission after waiting for different time periods, collisions can be minimized.

[0077] In addition, the IEEE 802.11 MAC protocol provides the Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method and refers to the method in which all receiving APs and / or STAs are periodically polled to receive data frames. In addition, the HCF has the Enhanced Distributed Channel Access (EDCA) and the HCF Controlled Channel Access (HCCA). The EDCA is a contention-based access method that provides data frames to multiple users in a direction, and the HCCA uses a contention-free channel access method that utilizes the polling mechanism. In addition, the HCF includes a medium access mechanism for improving the Quality of Service (QoS) of the wireless LAN and can transmit QoS data during the Contention Period (CP) and the Contention-Free Period (CFP).

[0078] Refer to Figure 4, operations based on a random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs can attempt to transmit data (or frames). As a method to minimize collisions, each of the STAs can separately select a random backoff count and attempt transmission after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values that vary from 0 to the value of CW. Here, CW is the value of the contention window parameter. The CW parameter is given the initial value of CWmin, but can take a value twice as large in the case of a transmission failure (e.g., when an ACK for the transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until the data transmission is successful, and when the data transmission is successful, the CWmin value is reset. The values of CW, CWmin, and CWmax are preferably set to 2n - 1 (n = 0, 1, 2,...).

[0079] When the random backoff process starts, the STA continuously monitors the medium during the countdown of the backoff slot according to the determined backoff count value. When monitoring the medium for occupancy, it stops the countdown and waits, and when the medium becomes idle, it resumes the remaining part of the countdown.

[0080] In Figure 4 the example, when the packet to be transmitted arrives at the MAC of STA 3, STA3 can transmit the frame immediately after confirming that the medium has been idle for up to DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. At the same time, the data to be transmitted can also occur in each of STA1, STA2, and STA5, and when the medium is monitored as idle, each STA waits for up to DIFS and then can perform the countdown of the backoff slot according to the random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, an example is shown where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 completes the backoff count and starts frame transmission. STA1 and STA5 temporarily stop the countdown and wait while STA2 occupies the medium. When the occupancy of STA2 ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and resume the stopped backoff count. That is, frame transmission can start after counting down the remaining backoff slots for the remaining backoff time. Since the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1, STA5 starts frame transmission. While STA2 occupies the medium, the data to be transmitted can also occur in STA4. From the perspective of STA4, when the medium becomes idle, STA4 can wait for DIFS and then can perform the countdown according to the random backoff count value selected by STA4 and start transmitting the frame. Figure 4The example shows a situation where the remaining backoff time of STA5 accidentally conflicts with the random backoff counter value of STA4. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, so the data transmission fails. In this case, STA4 and STA5 can double the CW value, select a random backoff counter value, and perform countdown. When the medium is occupied due to the transmissions of STA4 and STA5, STA1 waits. When the medium becomes idle, STA1 waits for DIFS and then starts frame transmission after the remaining backoff time has passed.

[0081] As in Figure 4 the example, a data frame is a frame for transmitting data forwarded to a higher layer and can be transmitted after a backoff performed after DIFS from when the medium becomes idle. Additionally, a management frame is a frame for exchanging management information not forwarded to a higher layer and is transmitted after a backoff performed after an IFS such as DIFS or Point Coordination Function IFS (PIFS). As subtype frames of the management frame, there are beacon, association request / response, re-association request / response, probe request / response, authentication request / response, etc. A control frame is a frame for controlling access to the medium. As subtype frames of the control frame, there are Request to Send (RTS), Clear to Send (CTS), Acknowledgment (ACK), Power Save Poll (PS-Poll), Block Ack (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP Announcement), and Trigger, etc. If a control frame is not a response frame to a previous frame, it is transmitted after a backoff performed after DIFS, and if it is a response frame to a previous frame, it is transmitted without performing a backoff after Short IFS (SIFS). The type and subtype of a frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0082] A Quality of Service (QoS) STA can perform a backoff performed after Arbitration IFS (AIFS) for the access category (AC) to which the frame belongs (i.e., AIFS (where i is a value determined by the AC)) and then can transmit the frame. Here, frames for which AIFS can be used can be data frames, management frames, or control frames other than response frames.

[0083] Figure 5 is a diagram for explaining the CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0084] As described above, in addition to the physical carrier sensing of the medium directly by the STA, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing aims to compensate for problems such as the hidden node problem that may occur in medium access. For virtual carrier sensing, the MAC of the STA can use the 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 current STA or the STA that has the right to use the medium. Therefore, the value set as the NAV corresponds to the period during which the STA that transmits the frame plans to use the medium, and during the corresponding period, the STA that receives the NAV value is prohibited from accessing the medium. For example, the NAV can be configured based on the value of the "Duration" field in the MAC header of the frame.

[0085] In Figure 5 the example, it is assumed that STA1 aims to send data to STA2, and STA3 is in a position where it can overhear some or all of the frames transmitted and received between STA1 and STA2.

[0086] To reduce the possibility of transmission conflicts among multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames can be applied. In Figure 5 the example, when the transmission of STA1 is being executed, as a result of the carrier sensing of STA3, it can be determined that the medium is in an idle state. That is, STA1 can correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 the example, it can be determined that when the transmission of STA2 is being executed, the carrier sensing result of STA3 indicates that the medium is in an idle state. That is, STA2 can correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2 or STAs outside the carrier sensing range of the transmission from STA1 or STA3 can refrain from attempting to occupy the channel during the data transmission and reception between STA1 and STA2.

[0087] Specifically, STA1 can determine whether the channel is being used through carrier sensing. In terms of physical carrier sensing, STA1 can determine the occupied or idle state of the channel based on the energy level or signal correlation detected in the channel. Additionally, in terms of virtual carrier sensing, STA1 can use the Network Allocation Vector (NAV) timer to determine the channel occupancy state.

[0088] When the channel is in an idle state during 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.

[0089] If STA3 cannot overhear the CTS frame from STA2 but can overhear the RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the transmission period of the frames continuously sent thereafter (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 can overhear the CTS frame from STA2, even though STA3 cannot overhear the RTS frame from STA1, STA3 can use the duration information included in the CTS frame to set the NAV timer for the transmission period of the frames continuously sent thereafter (e.g., SIFS + data frame + SIFS + ACK frame). That is, if STA3 can overhear one or more of the RTS frame or CTS frame from one or more of STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can use the duration information included in the new frame to update the NAV timer. STA3 does not attempt channel access until the NAV timer expires.

[0090] When STA1 receives the CTS frame from STA2, STA1 can send a data frame to STA2 after SIFS from the time point when the reception of the CTS frame is completed. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 can determine whether the channel is being used through carrier sensing. When STA3 determines during the DIFS period after the NAV timer expires that the channel is not being used by other terminals, STA3 can attempt channel access after the contention window (CW) based on random backoff has elapsed.

[0091] Figure 6 is a diagram for explaining an example of the frame structure used in a WLAN system to which the present disclosure can be applied.

[0092] With instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MAC PDU (MPDU) to be transmitted. For example, when receiving a command from the MAC layer to request the start of transmission from the PHY layer, the PHY layer switches to the transmission mode, configures the information (e.g., data) provided from the MAC layer in the form of a frame, and transmits it. In addition, when the PHY layer detects the valid preamble of the received frame, the PHY layer monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception by the PHY layer.

[0093] In this way, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, a PHY layer protocol data unit (PPDU) format is defined.

[0094] The basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., Figure 7 the non-HT (High Throughput) shown in

[0095] may consist only of a Legacy-STF (L-STF), a Legacy-LTF (L-LTF), a Legacy-SIG (L-SIG) field, and a Data field. Additionally, 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 fields, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) etc. may be included between the L-SIG field and the Data field.

[0096] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits, and the L-SIG field may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may include information about the modulation and coding rate of the data. For example, the 12-bit Length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined to be a multiple of 3. For example, for HE PPDU, the value of the Length field may be determined to be a multiple of 3 + 1 or 3 + 2.

[0097] The data field may include a SERVICE field, a Physical Layer Service Data Unit (PSDU), and PPDU tail bits, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bits may be used to return the encoder to the 0 state. The padding bits may be used to adjust the length of the data field in predetermined units.

[0098] The 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). The MAC frame may consist of MAC PDUs and be sent / received through the PSDU of the data part in the PPDU format.

[0099] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the corresponding frame, etc. For details of the Sequence Control, QoS Control, and HT Control sub-fields of the MAC header, refer to the IEEE 802.11 standard document.

[0100] The Null Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, the NDP refers to a frame format that includes the PPDU preamble of the general PPDU format (i.e., the L-STF, L-LTF, L-SIG fields, and additional non-traditional SIG, non-traditional STF, non-traditional LTF (if any)) and does not include the remaining part (i.e., the data field).

[0101] Figure 7 FIG. is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0102] 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 a data field. The basic PPDU format may also be referred to as a non-HT PPDU format (as shown in (a) of Figure 7 ).

[0103] Compared with the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields. Figure 7The HT PPDU format shown in (b) can be referred to as the HT mixed format. Additionally, an HT Greenfield format PPDU can be defined, and this corresponds to a format (not shown) 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.

[0104] Compared with the basic PPDU format, an example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (as Figure 7 shown in (c)).

[0105] Compared with the basic PPDU format, an example of the HE PPDU format (IEEE 802.11ax) additionally includes a Repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, and Packet Extension (PE) fields (as Figure 7 shown in (d)). Some fields can be excluded, or their lengths can vary according to the detailed example of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for Multi-User (MU), and the HE-SIG-B is not included in the HE PPDU format for Single-User (SU). Additionally, the HE Trigger-Based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field can vary up to 8 μs. The Extended Range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary up to 16 μs. For example, the RL-SIG can be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA can know that the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0106] The EHT PPDU format can include Figure 7 the EHT MU (Multi-User) in (e) and Figure 7 the EHT TB (Trigger-Based) PPDU in (f). The EHT PPDU format is similar to the HE PPDU format in including an RL-SIG following the L-SIG, but can include a U (Universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0107] Figure 7The EHT MU PPDU in (e) corresponds to a PPDU carrying one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0108] Compared with the EHT MU PPDU, Figure 7 the EHT TB PPDU in (f) omits the EHT-SIG. The STA that receives a trigger for UL MU transmission (e.g., a trigger frame or a triggered response schedule (TRS)) can perform UL transmission based on the EHT TB PPDU format.

[0109] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), and EHT-SIG fields can be encoded and modulated so that even a legacy STA can attempt to demodulate and decode, and can be mapped based on the determined subcarrier frequency spacing (e.g., 312.5 kHz). These can be referred to as pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, data, and PE fields can be encoded and modulated to be demodulated and decoded by an STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information included in this field, and can be mapped based on the determined subcarrier frequency spacing (e.g., 78.125 kHz). These can be referred to as EHT modulation fields.

[0110] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields can be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields can be referred to as VHT modulation fields.

[0111] Included in Figure 7The U-SIG in the EHT PPDU format can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 μs, and the U-SIG can have a total duration of 8 μs. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0112] The U-SIG can be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG can be replicated. That is, the same 4 U-SIGs can be included in the 80 MHz PPDU. A PPDU with a bandwidth exceeding 80 MHz can include different U-SIGs.

[0113] For example, A uncoded bits can be transmitted through the U-SIG. The first symbol of the U-SIG (e.g., the U-SIG-1 symbol) can 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) can 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) can include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). For example, the tail field can be used to terminate the trellis structure of the convolutional decoder and can be set to 0.

[0114] The bit information transmitted through the U-SIG can be divided into version-independent bits and version-dependent bits. For example, the U-SIG can be included in Figure 7 a new PPDU format (e.g., the UHR PPDU format) not shown, and can be included in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format. The version-independent bits can be the same, and some or all of the version-dependent bits can be different.

[0115] For example, the size of the version-independent bits of the U-SIG can be fixed or variable. The version-independent bits can be assigned only to the U-SIG-1 symbol, or assigned to both the U-SIG-1 symbol and the U-SIG-2 symbol. The version-independent bits and the version-dependent bits can be called various names, such as the first control bit and the second control bit.

[0116] For example, the version-independent bits of the U-SIG can include a 3-bit Physical Layer Version Identifier (PHY version identifier), and this information can indicate the PHY version of the transmitted / received PPDU (e.g., EHT, UHR, etc.). The version-independent bits of the U-SIG can 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 can include information about the length of the Transmission Opportunity (TXOP) and information about the BSS Color ID.

[0117] For example, the version-dependent bits of the U-SIG can include information that directly or indirectly indicates the type of the PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0118] The information required for PPDU transmission and reception can be included in the U-SIG. For example, the U-SIG can also include information about the bandwidth, information about the MCS technique applied to non-traditional SIGs (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether the DCM (Dual Carrier Modulation) technique (e.g., a technique for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to non-traditional SIGs, information about the number of symbols for non-traditional SIGs, information about whether non-traditional SIGs are generated across the entire frequency band.

[0119] Some of the information required for PPDU transmission and reception can be included in the U-SIG and / or non-traditional SIGs (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of non-traditional LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of non-traditional LTF and the CP (Cyclic Prefix) length, information about the GI (Guard Interval) applicable to non-traditional LTF, information about the preamble punching applicable to the PPDU, information about the Resource Unit (RU) allocation, etc. can be included only in the U-SIG, only in the non-traditional SIG, or can be indicated by a combination of the information included in the U-SIG and the information included in the non-traditional SIG.

[0120] Preamble punching can represent the transmission of the following PPDU, where there is no signal in one or more frequency units among the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble punching) can be defined as 20 MHz, 40 MHz, etc. For example, preamble punching can be applied to a PPDU bandwidth of a predetermined size or larger.

[0121] In Figure 7In the example, non - traditional SIGs such as HE - SIG - B and EHT - SIG can include control information for receiving STAs. The non - traditional SIG can be sent on at least one symbol, and one symbol can have a length of 4 μs. Information about the number of symbols for EHT - SIG can be included in a previous SIG (e.g., HE - SIG - A, U - SIG, etc.).

[0122] Non - traditional SIGs such as HE - SIG - B and EHT - SIG can include a common field and user - specific fields. The common field and user - specific fields can be encoded separately.

[0123] In some cases, the common field can be omitted. For example, in a compressed mode that does not apply OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive a PPDU (e.g., the data field of the PPDU) through the same frequency band. In a non - compressed mode that applies OFDMA, multiple users can receive a PPDU (e.g., the data field of the PPDU) through different frequency bands.

[0124] The number of user - specific fields can be determined based on the number of users. One user block field can include up to two user fields. Each user field can be associated with MU - MIMO allocation or can be associated with non - MU - MIMO allocation.

[0125] The common field can include CRC bits and tail bits. The length of the CRC bits can be determined to be 4 bits, and the length of the tail bits can be determined to be 6 bits and set to 000000. The common field can include RU allocation information. The RU allocation information can include information about the positions of the RUs assigned to multiple users (i.e., multiple receiving STAs).

[0126] An RU can include multiple sub - carriers (or tones). When sending signals to multiple STAs based on OFDMA technology, RUs can be used. Additionally, even when sending signals to one STA, RUs can be defined. Resources can be allocated to non - traditional STF, non - traditional LTF, and data fields in units of RUs.

[0127] The RU of an applicable size can be defined according to the PPDU bandwidth. The RU can be defined identically or differently for the applied PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU layouts of the HE PPDU and the EHT PPDU can be different. The applicable RU size, the number of RUs, the RU positions, the DC (direct current) subcarrier positions and number, the null subcarrier positions and number, the guard subcarrier positions and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, the tone plan for high bandwidth can be defined in the form of multiple iterations of a low bandwidth tone plan.

[0128] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. An MRU (multi-RU) is different from multiple individual RUs and corresponds to a set of subcarriers composed of multiple RUs. For example, an MRU can be defined as 52 + 26 tones, 106 + 26 tones, 484 + 242 tones, 996 + 484 tones, 996 + 484 + 242 tones, 2×996 + 484 tones, 3×996 tones, or 3×996 + 484 tones. Additionally, the multiple RUs constituting an MRU can be continuous or non-continuous in the frequency domain.

[0129] The specific size of the RU can be reduced or extended. Therefore, the specific size (i.e., the number of corresponding tones) of each RU in this disclosure is illustrative rather than restrictive. Additionally, in this disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz...), the number of RUs can vary according to the RU size.

[0130] Figure 7 The name of each field in the PPDU format is exemplary, and the scope of this disclosure is not limited by these names. Additionally, the examples of this disclosure can be applied to Figure 7 the PPDU format shown in Figure 7 and new PPDU formats that exclude some fields and / or add some fields based on the

[0131] Method for Sending and Receiving Relay Frames Controlled by AP

[0132] In the next-generation wireless LAN system (e.g., next-generation Wi-Fi, standards after IEEE 802.11be, etc.), in order to support ultra-high reliability (UHR) in signal transmission to the STA, various technologies are being considered to support high throughput, low latency, extended range, etc.

[0133] The method proposed in this disclosure relates to a method of using a relay method controlled by an AP to send signals to an STA to extend the coverage range / distance, so as to be reliably sent to various IoT devices and outdoor devices. Specifically, a data structure for sending signals using a relay STA (for example, PPDU, A-MPDU) and a signaling method for this relay are proposed.

[0134] In the case of the method proposed in this disclosure, considering the ease of relay implementation and the complexity of operation, it can be based on a relay transmission method controlled by an AP.

[0135] For the sake of clarity, in the following embodiments of this disclosure, the relay STA controlled by an AP is referred to as an AP-controlled relay STA (ACRS).

[0136] For example, the ACRS performs relay transmission on the data received from the AP within the BSS, and at this time, all controls of the ACRS for relay can be performed by the corresponding AP. That is, the ACRS can send the signal (for example, data frame) received from the AP to the end user / STA based on the information received from the AP.

[0137] Here, the ACRS can correspond to an independent relay device that only performs relay transmission, or can correspond to a non-AP STA that supports relay.

[0138] The following disclosure specifically proposes a process for initiating ACRS-based relay transmission performed between an AP and an ACRS (hereinafter referred to as Embodiment 1), and a relay transmission process performed after this process (hereinafter referred to as Embodiment 2).

[0139] The embodiments described below are only distinguished for the sake of clarity, and some components of one embodiment can be replaced by some components of another embodiment or can be combined and applied.

[0140] Embodiment 1

[0141] This embodiment relates to a negotiation / association and initiation process performed between an AP and a relay STA related to relay transmission.

[0142] The ACRS that relays data to an STA under the control of an AP can use a (re)association request / response frame or a probe request / response frame to indicate that the ACRS is a relay STA or an STA that supports relay transmission. At this time, the frame can be configured to include a relay support field, relay transmission capabilities, and / or relay operation elements.

[0143] For example, the AP can identify the relay STA (i.e., ACRS) by using the relay support field, relay transmission capability, and / or negotiation of the relay operation element, and can assign an ID to the identified relay STA. As an example, the ID of the relay STA (e.g., RSID) can be configured as a specific ID of the STA ID.

[0144] That is, the relay STA (i.e., ACRS) can be associated with the AP through the exchange process of the (re) association request / response frame or probe request / response frame as described above.

[0145] The AP can obtain the information of the relay STA through the above association process, and the AP can execute the initiation process for performing relay transmission within the BSS.

[0146] In this regard, in order to initiate the above relay transmission, the AP can send a request frame to the relay STA and receive a response frame for the request frame from the relay STA.

[0147] Figure 8 Illustrated is the negotiation / association and initiation process related to relay transmission between the AP and the relay STA according to an embodiment of the present disclosure.

[0148] Refer to Figure 8 , the relay STA can correspond to a non-AP STA that performs relay transmission controlled by the AP.

[0149] The relay STA can send a request frame related to relay transmission negotiation / association to the AP (S810). In response, the AP can send a response frame to the relay STA (S820). For example, a probe / (re) association request frame can be used as the request frame, and a probe / (re) association response frame can be used as the response frame.

[0150] In this regard, the request frame in step S810 and the response frame in step S820 can be composed of a relay support field, relay transmission capability, and / or relay operation element.

[0151] Thereafter, the AP can send a specific request frame to the relay STA to initiate relay transmission (S830), and the relay STA can send a response frame to the AP (S840).

[0152] For example, the specific request frame can correspond to a poll frame or a relay operation request frame, and the response frame can correspond to a CTS frame or a relay operation response frame.

[0153] In the following disclosure, for the sake of clarity, the case of initiating relay transmission via a poll frame is described as a representative example. The method proposed in the present disclosure is not limited to the frame name, and can be extended to the case where it is replaced with another frame name having the same function and information.

[0154] In order to use the relay STA identified by the AP through the negotiation / association process to initiate relay transmission, the AP may send a poll frame to the relay STA. For example, the poll frame sent by the AP may be defined as a relay operation request frame or a relay initiation frame.

[0155] In this regard, the poll frame sent by the AP may include a relay support / request field, a relay mode field, a relay transmission related ID field, a relay transmission parameter field, an RU allocation field, and / or an immediate ACK support field.

[0156] Each field included in the poll frame is described in detail below.

[0157] For example, the relay support / request field indicates support for or a request for relay transmission. This field may be configured as 1 bit. In this case, setting this field to the value 1 may indicate a request for relay transmission. In this regard, the specific bit value configuration may also be the opposite.

[0158] For example, the relay mode field may indicate whether it is a single transmission or a group transmission. Here, a single transmission refers to the case where the relay transmission targets a single STA, while a group transmission refers to the case where the relay transmission targets multiple STAs or a group of STAs. This field may be configured with 1 bit. In this case, the value 0 may be defined to indicate a single transmission, and the value 1 may be defined to indicate a group transmission. In this regard, the specific bit value configuration may also be the opposite.

[0159] For example, regarding the relay transmission related ID field, the poll frame may include one or more of source ID information, destination ID information, relay ID information, the number of STAs used for relay information, or relay STA list information.

[0160] Specifically, the source ID information indicates the ID information of the STA that initiates the relay transmission and may be set to the ID of the AP or the BSSID.

[0161] The destination ID information indicates the ID information of the STA that is the target of the relay transmission. In the case of transmission to a single STA (i.e., when the relay mode field is set to the value 0), the destination ID information may be set to the ID of the final STA that receives the signal / data through the relay transmission, the STA-ID information. In the case of transmission to a group of STAs or multiple STAs (i.e., when the relay mode field is set to the value 1), the destination ID information may be set to the group ID (GID).

[0162] The relay ID information may indicate the ID information of the relay STA that performs the relay transmission and may be set to the ID assigned by the AP when associating with the AP.

[0163] The number information of STAs for relay indicates the number of STAs that send and receive signals / data through relay, i.e., the number of STAs participating in the transmission.

[0164] The relay STA list information indicates the information of STAs participating in the relay transmission and can be composed of the ID information of the corresponding STAs.

[0165] For example, the relay transmission parameter field can be composed of a combination of one or more of bandwidth (BW) information, modulation and coding scheme (MCS) difference information, MCS information, and N_STS information.

[0166] Specifically, the bandwidth information indicates the information of the bandwidth used for relay transmission and can indicate, for example, 20 MHz, 40 MHz, 80 MHz, 160 MHz, and / or 320 MHz.

[0167] The MCS difference information can indicate whether the relay operation supports using different MCSs for reception from the AP and transmission to the STA. For example, the MCS difference information can be composed of 1 bit. In this case, the value 0 can indicate non - support, and the value 1 can indicate support. Additionally or alternatively, the MCS difference information can be used to indicate the difference in MCS values used by the relay when sending and receiving signals. For example, this information / sub - field can be used to indicate a difference of 0, 1, 2, 3, and 4.

[0168] The MCS information indicates the MCS value used in the relay transmission. In this regard, since the relay transmission can consider a generally high SNR, the corresponding MCS value can be limited to values indicating 16QAM to 256QAM. Additionally or alternatively, the corresponding MCS information can be used to indicate the maximum MCS (max MCS) value used in the relay transmission.

[0169] The N_STS information indicates the value of the number of space - time streams (STS) used in the relay transmission and can be composed of 3 bits.

[0170] For example, the RU allocation field indicates the information of the RU resources allocated for the relay STA to send a response frame.

[0171] For example, the immediate ACK support field indicates whether immediate ACK transmission is supported after receiving data from the AP. This field is composed of 1 bit, and setting it to the value 1 can be defined as indicating support for immediate ACK, and setting it to the value 0 can be defined as indicating ACK transmission through a request frame. In this regard, the specific bit - value configuration can also be the opposite case.

[0172] A relay STA that receives a poll frame configured as described above from an AP may send a response frame to the AP to indicate whether it accepts relay transmission.

[0173] At this time, a CTS frame or a relay operation response frame may be used as the response frame.

[0174] If a CTS frame is used as the response frame, only the relay STA that can perform the relay transmission requested by the AP may send a CTS frame to the AP after a SIFS following the reception of the poll frame (i.e., the request frame). At this time, the RU assigned by the AP to the relay STA (e.g., the RU assignment field in the above poll frame) may be used to send the CTS frame.

[0175] The AP may determine whether the relay STA participates in the relay transmission based on whether it receives the CTS frame.

[0176] Conversely, when the relay operation response frame is used as the response frame, the response frame may be sent after a SIFS following the reception of the request frame. Here, the response frame may include a relay STA ID field, a status field, a relay operation parameter field, and / or an immediate ACK field.

[0177] For example, the relay STA ID field indicates the ID information of the relay STA that sends the response frame.

[0178] For example, the status field indicates whether the AP accepts the requested relay transmission and may be set to success, deny, deny and performance parameters. Here, success indicates acceptance of the relay transmission, deny indicates rejection of the relay transmission, and deny and performance parameters may indicate rejection of the current relay transmission and transmission with preferred relay transmission parameters.

[0179] For example, the relay operation parameter field may be set to information on parameters that the relay STA prefers / expects to use when sending a relay. For example, this field may be configured as a combination of MCS information, MCS difference information, N_STS information, etc. In this regard, if the status field is set to success or deny, the relay operation parameter field may not be included in the response frame. The relay operation parameter field may be included in the response frame only when the status field is set to deny and performance parameters.

[0180] For example, the immediate ACK support field indicates whether to perform immediate ACK transmission or requested ACK transmission when the relay STA sends an ACK transmission after receiving data from the AP.

[0181] Regarding the above-mentioned association / negotiation process, there may be no need for a separate link / association process between the relay STA and the STA that is the target of relay transmission (i.e., the final STA). This is because both the relay STA and the final STA correspond to non-AP STAs associated with the AP, and the relay transmission is controlled by the AP.

[0182] Embodiment 2

[0183] This embodiment relates to a relay transmission process performed among an AP, a relay STA, and a STA that is the target of relay transmission (e.g., the final STA).

[0184] When relay transmission is determined by request / response frame exchange between the AP and the relay STA as in Embodiment 1, the AP may send data to the relay STA to send data to the STA that is the target of relay transmission (i.e., the intended STA, the final STA, the addressed STA). In the following embodiments, for clarity of explanation, the STA that is the target of relay transmission is referred to as the final STA.

[0185] The relay STA that receives data from the AP may use the same channel that the AP uses to send data to the relay STA to send the data / signals received from the AP to the final STA.

[0186] As described above, since the relay STA uses the same channel as the AP to send and receive signals, the AP does not need to separately signal the channel information for relay transmission to the relay STA. As described above, the relay STA uses the time-division duplex (TDD) method to send and receive signals and may perform transmission and reception within the TXOP allocated from the AP.

[0187] Figure 9 An example of a relay transmission process according to an embodiment of the present disclosure is illustrated.

[0188] Refer to Figure 9 where "AP" corresponds to the AP that initiates relay transmission, "repeater" corresponds to the relay STA that forwards the relay frame received from the AP, and "STA" corresponds to the final STA that is the target of relay transmission.

[0189] The AP may send data (e.g., a data frame) targeted at the final STA to the relay STA (S910).

[0190] The relay STA that receives data from the AP may send an ACK frame for the received data to the AP after SIFS (S920). The ACK frame indicates whether the received signal / data has been successfully received, and additionally or alternatively, the ACK frame may be sent together with indication information indicating that relay transmission will be performed.

[0191] At this time, the transmission of the ACK frame can be performed according to the ACK policy negotiated between the AP and the relay STA.

[0192] After transmitting the ACK frame to the AP, the relay STA can transmit the data received from the AP to the final STA after the SIFS (S930).

[0193] The final STA that receives the data from the relay STA can transmit an ACK frame to the relay STA to indicate whether the data has been received (S940).

[0194] For example, when performing relay transmission targeting one final STA, as exemplified in Figure 9 the ACK frame can be transmitted in an immediate ACK manner after the SIFS following data reception.

[0195] The relay STA that receives the ACK frame from the final STA can transmit an ACK frame to the AP after the SIFS following the reception of the ACK frame (S950). At this time, the ACK frame transmitted by the relay STA to the AP can include identification information (e.g., ID) for the final STA, ACK indication information, etc.

[0196] Figure 10 Illustrate another example of the relay transmission process according to an embodiment of the present disclosure.

[0197] Refer to Figure 10 where "AP" corresponds to the AP that initiates the relay transmission, "repeater" corresponds to the relay STA that forwards the relay frame received from the AP, and "STA" corresponds to multiple final STAs that are the targets of the relay transmission.

[0198] Figure 10 The process in Figure 10 corresponds to the process of performing relay transmission for multiple final STAs (or a group of final STAs). In this regard, in the case of the process in Figure 9 compared with the process in

[0199] Figure 10 the steps S1010 to S1030 and S1050 in Figure 9 are the same as the descriptions of the steps S910 to S930 and S950 in

[0200] and thus redundant specific descriptions are omitted. As described above, after the relay STA transmits the data received from the AP to multiple final STAs, in order to receive ACK frames from the multiple final STAs, the relay STA can transmit a block ACK request frame to the multiple final STAs after the SIFS (S1035). By transmitting the block ACK request frame, solicitation of ACK frame transmission from each STA can be made.

[0201] Therefore, after sending the block ACK request frame, after the SIFS, the relay STA can receive ACK frames from each STA belonging to multiple final STAs (S1040).

[0202] Regarding the relay transmission process described above in the present disclosure, the TXOP for performing relay transmission can be set as described in the following examples. For example, the TXOP can be set by the AP that initiates the relay transmission.

[0203] For example, the AP sets the TXOP for the entire period of relay transmission, and the TXOP can be set as follows.

[0204] -TXOP = transmission PPDU length from the AP to the relay STA (e.g., ACRS) + SIFS + ACK length from the relay STA to the AP + SIFS + transmission PPDU length from the relay STA to the final STA (e.g., the STA targeted for relay transmission) + SIFS + ACK length from the final STA to the relay STA + SIFS + ACK length from the relay STA to the AP

[0205] Additionally, when adding a block ACK request transmission process for multiple final STAs such as the foregoing Figure 10 the block ACK request transmission time and the associated SIFS can be additionally applied to the TXOP configuration.

[0206] In this regard, the TXOP set as described above can be sent by being included in the PPDU sent by the AP to the relay STA for relay transmission, and the TXOP value can be sent by being included in the U-SIG field of the corresponding PPDU.

[0207] Additionally, the TXOP of the PPDU sent by the relay STA to the final STA can be set as follows.

[0208] -TXOP_repeater to STA = transmission PPDU length from the relay STA to the final STA + SIFS + ACK length from the final STA to the relay STA + SIFS + ACK length from the relay STA to the AP

[0209] Here, the TXOP_repeater to STA included in the PPDU sent by the relay STA to the final STA can be set to a value less than the TXOP value set by the AP for sending a signal to the relay STA.

[0210] In this regard, the TXOP_repeater to STA set as described above can be sent by being included in the U-SIG field of the PPDU sent by the relay STA to the final STA.

[0211] Hereinafter, in the present disclosure, an ACK frame and an ACK transmission method for relay transmission are described in connection with the relay transmission process described above in the present disclosure.

[0212] The PPDU sent from the AP to the relay STA can be sent in the format of an aggregated MAC service data unit (A-MSDU) or an aggregated MAC protocol data unit (A-MPDU), and can be based on the frame format structure as Figure 11 shown.

[0213] Figure 11 The format of the relay frame applicable to the embodiments of the present disclosure is illustrated.

[0214] Referring to Figure 11 (a) of, the PPDU based on the A-MSDU may include one MAC header. In contrast, referring to Figure 11 (b) of, the PPDU based on the A-MPDU may include the MAC headers of each subframe constituting the A-MPDU.

[0215] Using the frame format structure as Figure 11 such, the data sent from the AP to the relay STA may include information about one or more final STAs. However, this data / signal is not directly sent to the final STA, but is sent through the relay STA. Therefore, in the case of relay transmission targeting multiple final STAs, if all the MAC headers included in the PPDU are decoded, verified, and an ACK is sent, unnecessary delays may occur.

[0216] In view of this, in order to notify the AP whether the signal / data has been received from the AP, the relay STA may be configured to send an ACK frame to the AP by considering the first MAC header and FCS of the received signal / data. Here, the FCS may correspond to the field for error detection included in the corresponding PPDU (e.g., a 32-bit CRC field). Alternatively, the ACK frame may be determined based on whether the first MAC header has been received.

[0217] That is, when using the A-MPDU structure for relay transmission targeting multiple STAs, the ACK frame transmission (e.g., the ACK frame sent from the relay STA to the AP) can be performed by considering the MAC header and FCS of the MPDU constituting the first subframe belonging to the A-MPDU.

[0218] As described above, since the ACK is determined only by the [first MAC header and FCS] or [first MAC header] of the received signal / data, there is a technical effect of reducing delays by allowing the omission of upper-layer MAC-level operations.

[0219] The ACK frame sent by the relay STA to the AP can be sent after the SIFS after receiving data from the AP.

[0220] Additionally or alternatively, if the AP does not receive an ACK frame from the relay STA within the SITF after completing signal / data transmission or within the expiration time determined / set when initiating the association / relay operation with the relay STA, the AP can terminate the relay operation.

[0221] In this regard, the termination of the relay operation can be performed by the AP sending a termination frame to the relay STA. Additionally or alternatively, as described above, the relay operation can be defined to terminate when the expiration time determined / set when initiating the association / relay operation has passed without receiving an ACK frame.

[0222] Therefore, the ACK operation for relay transmission proposed in the present disclosure can be performed as follows.

[0223] - Step 1. The relay STA can receive signals / data for relay operation / transmission from the AP.

[0224] - Step 2. The relay STA that has received signals / data from the AP can, after receiving the MAC header of the first MPDU / first subframe of the received PPDU and checking the FCS, send an ACK frame to the AP including information indicating that it has received signals / data from the AP.

[0225] Here, the ACK frame can include indication information indicating the execution of the relay operation / transmission. Additionally, the ACK policy for signal / data transmission from the AP to the relay STA can be set to immediate ACK transmission, i.e., implicit ACK transmission. Here, immediate ACK transmission can mean ACK transmission performed after the SIFS after signal / data reception.

[0226] By sending the above ACK frame, the TXOP set by the AP can be maintained and the relay operation / transmission can be protected. Additionally, if it is determined that the relay STA has not received the information in the MAC header or has received an incorrect MAC header, the ACK / ACK frame transmission may not be performed.

[0227] - Step 3. After sending the ACK frame to the AP, the relay STA can send signals / data (i.e., the signals / data received from the AP) to the final STA after the SIFS.

[0228] - Step 4. If the AP does not receive an ACK frame from the relay STA within a certain period of time after sending signals / data to the relay STA, the AP can terminate the relay transmission and also terminate the associated TXOP. Here, the certain period of time can correspond to one or more of the SIFS, ACK duration, or expiration time.

[0229] Hereinafter, with reference to Figure 12 and Figure 13 the operation of the STA according to the above-described embodiments of the present disclosure will be described.

[0230] That is, Figure 12 and Figure 13 the examples of can correspond to some of the various examples of the present disclosure. For example, in Figure 12 and Figure 13 the first STA may correspond to a relay STA (e.g., ACRS), and the second STA may correspond to the target STA (i.e., the final STA) of the relay transmission.

[0231] Figure 12 FIG. illustrates a flowchart of operations performed by the first STA according to an embodiment of the present disclosure.

[0232] With reference to Figure 12 the first STA may correspond to a non-AP STA controlled by an AP for relay transmission.

[0233] The first STA may receive a request frame (e.g., a poll frame, a relay operation request frame described above in the present disclosure) related to the initiation of a relay operation targeting one or more second STAs from the AP (S1210).

[0234] Here, the request frame may include ID information (e.g., destination ID information) for identifying one or more second STAs as the destinations of the relay operation.

[0235] For example, the corresponding ID information may be set based on the mode of the relay operation indicated by relay mode-related information (e.g., a relay mode field) included in the request frame of step S1210. As a specific example, if the mode of the relay operation corresponds to a mode targeting a single second STA (e.g., a single transmission mode), the corresponding ID information may be set to the ID of the single second STA. Conversely, if the mode of the relay operation corresponds to a mode targeting multiple second STAs (e.g., a group transmission mode), the corresponding ID information may be set to a specific ID (e.g., a group ID) for grouping the multiple second STAs.

[0236] Additionally or alternatively, the request frame may further include ID information (e.g., source ID information) for identifying the AP as the source of the relay operation and ID information (e.g., relay ID information) for identifying the first STA as the repeater of the relay operation.

[0237] Additionally or alternatively, the request frame may include at least one of information on the number of second STAs participating in the relay operation or information on a list of IDs of second STAs participating in the relay operation.

[0238] Additionally or alternatively, the request frame may include one or more parameters related to the relay operation. Here, the one or more parameters may include one or more of bandwidth information for the relay operation, modulation and coding scheme (MCS) information, MCS difference-related information, or spatial stream number information. In this regard, the MCS difference-related information may include at least one of information indicating whether different MCSs are applicable to the transmission and reception of the first STA in the relay operation or information indicating the difference in MCS values applied to the transmission and reception of the first STA in the relay operation.

[0239] Additionally or alternatively, the request frame may further include resource unit (RU) allocation information for sending a response frame thereto, information indicating whether immediate ACK frame transmission is supported for a data frame received from the AP, and the like.

[0240] The first STA may send a response frame to the request frame of step S1210 (S1220).

[0241] For example, the response frame may be sent via the resources indicated by the RU allocation information included in the request frame.

[0242] In this regard, the response frame may correspond to either a clear to send (CTS) frame or a frame including one or more fields related to the relay operation. Here, the one or more fields may include at least one of the following: a first field (e.g., relay STA ID field) indicating the ID information of the STA (i.e., the first STA) sending the response frame, a second field (e.g., status field) indicating whether to accept the relay operation, a third field (e.g., relay operation parameter field) indicating parameters related to the relay operation, and a fourth field (e.g., immediate ACK field) indicating whether to send an immediate ACK. In this case, the third field may be included or not according to the value indicated by the second field.

[0243] If the initiation of the relay operation is accepted through the above process, the first STA may receive a physical layer protocol data unit (PPDU) including data based on the relay operation from the AP (S1230). That is, the data may be targeted at one or more second STAs. Here, the U-SIG field of the PPDU may include TXOP information for the above relay operation.

[0244] After receiving a PPDU including corresponding data from an AP, the first STA may send a PPDU including the corresponding data to one or more second STAs after an SIFS (S1240). Here, the U-SIG field of the corresponding PPDU may include TXOP information (e.g., TXOP_Repeater-to-STA) related to the procedure between the first STA and the second STA in the above relay operation.

[0245] Additionally, after receiving a PPDU including the data in step S1230, the first STA may send an ACK frame to the AP after an SIFS. At this time, the ACK information (e.g., whether an ACK is received) in the ACK frame may be set based on whether a MAC header (and FCS check) included in the PPDU including the data is received. For example, if the PPDU including the data is configured with one or more subframes and configured with the A-MPDU frame format, a MAC header related to the ACK information may correspond to the MAC header in the first subframe among the one or more subframes. Another example, if the PPDU including the data is configured with one or more subframes and configured with the A-MSDU frame format, a MAC header related to the ACK information may correspond to the MAC header included in the A-MSDU frame format.

[0246] Additionally, if the PPDU including the data in step S1240 is sent to a single second STA (e.g., in the case of a separate transmission related to the relay operation), the first STA may be configured to receive an ACK frame from the single second STA after an SIFS after sending the PPDU including the corresponding data; and send an ACK frame to the AP after an SIFS after receiving the ACK frame from the single second STA. Alternatively, if the PPDU including the data in step S1240 is sent to multiple second STAs (e.g., in the case of a group transmission related to the relay operation), the first STA may be configured to send a block ACK request frame to the multiple second STAs after an SIFS after sending the PPDU including the corresponding data; and receive an ACK frame from the multiple second STAs after an SIFS after sending the block ACK request frame; and send an ACK frame to the AP after an SIFS after receiving the ACK frame from the multiple second STAs.

[0247] Figure 12 The method performed by the first STA described in the example of Figure 1 The first device (100) of Figure 1One or more processors (102) of the first device (100) may be configured to receive, via one or more transceivers (106), a request frame related to the initiation of a relay operation from an AP, send a response frame for the request frame to the AP, receive a PPDU including data based on the corresponding relay operation from the AP, and send a PPDU including the corresponding data to a second STA. In addition, one or more memories (104) of the first device (100) may store instructions that, when executed by one or more processors (102), are used to perform Figure 13 the example or the method described in the above example.

[0248] Figure 13 Illustrates a flowchart of operations performed by an AP according to an embodiment of the present disclosure.

[0249] Referring to Figure 13 , the first STA may correspond to a non-AP STA controlled by the AP for relay transmission.

[0250] The AP may send a request frame (S1310) related to the initiation of a relay operation targeting one or more second STAs to the first STA.

[0251] In this regard, the request frame may include ID information for identifying one or more second STAs as the destinations of the relay operation.

[0252] The AP may receive a response frame for the request frame from the first STA (S1320), and send a PPDU including data based on the above relay operation to the first STA (S1330).

[0253] Figure 13 Specific descriptions of information included in the request frame in Figure 12 , information included in the response frame, transmission and reception of ACK frames related to the relay operation, etc. are the same as those described in

[0254] Figure 13 The method performed by the AP described in the example of Figure 1 may be performed by Figure 1 a second device (200) ofFigure 13 Examples or the methods described in the above examples.

[0255] In existing wireless LAN systems, although general relay operations are defined, there is no specified relay method for using a non-AP STA controlled by an AP as a relay STA. Considering this, the method proposed in the present disclosure is a relay method for using a non-AP STA controlled by an AP as a relay STA, and as in the present disclosure, a process / information for initiating a relay operation and a specific relay operation process need to be newly defined. The method proposed in the present disclosure can reduce the influence of distance and obstacles by using a repeater to perform signal transmission to a STA, and can achieve technical effects of reducing latency and improving throughput by improving the received SNR of the STA.

[0256] The above-described embodiments combine the elements and features of the present disclosure in a predetermined form. Unless otherwise clearly mentioned, each element or feature should be regarded as optional. Each element or feature can be implemented in a form that does not combine with other elements or features. Additionally, the embodiments of the present disclosure can include combining some elements and / or features. The order of operations described in the embodiments of the present disclosure can be changed. Some elements or features of one embodiment can be included in other embodiments, or can be replaced with corresponding elements or features of other embodiments. Obviously, the embodiments can include combining claims that do not have an explicit citation relationship in the claims, or can be included as new claims through amendment after the application.

[0257] Those skilled in the relevant art will appreciate that the present disclosure can be implemented in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be construed restrictively in every aspect, but should be considered illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0258] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that perform operations according to various embodiments in a device or computer, and non-transitory computer-readable media that cause the software or instructions, etc. to be stored and executable in the device or computer. Instructions that can be used to program a processing system for performing the features described in the present disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in the present disclosure can be implemented by using a computer program product including such a storage medium. The storage medium can include high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, but is not limited thereto, and it can include non-volatile memory, such as one or more disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices located remotely from the processor. The memory, or alternatively, the non-volatile memory device in the memory, includes a non-transitory computer-readable storage medium. The features described in the present disclosure can be stored in any kind of machine-readable medium to control the hardware of the processing system, and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from the embodiments of the present disclosure. Such software or firmware can include application code, device drivers, operating systems, and execution environments / containers, but is not limited thereto.

[0259] Industrial Applicability

[0260] The method proposed in the present disclosure is mainly described based on examples applied to IEEE 802.11-based systems, but can be applied to various WLAN or wireless communication systems other than IEEE 802.11-based systems.

Claims

1. A method performed by a first station STA in a wireless LAN system, the method comprising: Receiving, from an access point AP, a request frame related to initiation of a relay operation targeted at one or more second STAs; Sending, to the AP, a response frame for the request frame; Receiving, from the AP, a physical layer protocol data unit PPDU including data based on the relay operation; And Sending, to the one or more second STAs, the PPDU including the data, Wherein the request frame includes ID information for identifying the one or more second STAs as destinations of the relay operation.

2. The method according to claim 1, Among them, Setting the ID information based on a mode of the relay operation indicated by relay mode-related information included in the request frame.

3. The method according to claim 1, Among them, Based on the mode of the relay operation corresponding to a mode targeted at a single second STA, setting the ID information to the ID of the single second STA, and Wherein, based on the mode of the relay operation corresponding to a mode targeted at multiple second STAs, setting the ID information to a specific ID for grouping the multiple second STAs.

4. The method according to claim 1, Among them, The request frame further includes ID information for identifying the AP as a source of the relay operation and ID information for identifying the first STA as a relay of the relay operation.

5. The method according to claim 1, Among them, The request frame includes at least one of information on the number of second STAs participating in the relay operation or information on a list of IDs of second STAs participating in the relay operation.

6. The method according to claim 1, Among them, The request frame includes one or more parameters related to the relay operation, and Wherein the one or more parameters include one or more of bandwidth information for the relay operation, modulation and coding scheme MCS information, MCS difference-related information, or number of spatial streams information.

7. The method according to claim 6, Among them, The MCS difference-related information includes at least one of information indicating whether different MCSs are applicable to transmission and reception by the first STA in the relay operation or information indicating a difference in MCS values applied to transmission and reception by the first STA in the relay operation.

8. The method according to claim 1, Among them, The request frame includes resource unit RU allocation information for sending the response frame, and Wherein the response frame is sent through a resource according to the RU allocation information.

9. The method according to claim 1, Among them, The request frame further includes information indicating whether immediate ACK frame transmission is supported for data frames received from the AP.

10. The method according to claim 1, Among them, The response frame corresponds to one of a clear to send CTS frame or a frame including one or more fields related to the relay operation.

11. The method according to claim 10, Among them, The one or more fields include at least one of the following: a first field indicating ID information of the STA that sent the response frame, a second field indicating whether to accept the relay operation, a third field indicating parameters related to the relay operation, and a fourth field indicating whether to send an immediate ACK.

12. The method according to claim 11, Among them, determine whether to include the third field based on the value indicated by the second field.

13. The method according to claim 1, the method further comprising: sending an ACK frame to the AP after a SIFS after receiving the PPDU including the data, wherein the ACK information in the ACK frame is set based on whether a MAC header and FCS check included in the PPDU including the data have been received.

14. The method according to claim 13, Among them, configuring the PPDU including the data based on using an A-MPDU frame format including one or more subframes, and the one MAC header corresponds to the MAC header in the first subframe among the one or more subframes.

15. The method according to claim 13, Based on sending the PPDU including the data to a single second STA, the method further includes: receiving an ACK frame from the single second STA after a SIFS after sending the PPDU including the data; and sending an ACK frame to the AP after a SIFS after receiving the ACK frame from the single second STA, based on sending the PPDU including the data to a plurality of second STAs, the method further comprises: sending a block ACK request frame to the plurality of second STAs after a SIFS after sending the PPDU including the data; receiving an ACK frame from the plurality of second STAs after a SIFS after sending the block ACK request frame; and sending an ACK frame to the AP after a SIFS after receiving the ACK frame from the plurality of second STAs.

16. The method according to claim 1, Among them, the U-SIG field of the PPDU received from the AP includes TXOP information for the relay operation.

17. The method according to claim 1, Among them, the first STA corresponds to a non-AP STA controlled by the AP for relay transmission.

18. An apparatus for a first station STA in a wireless local area network WLAN system, the apparatus comprising: at least one transceiver; and at least one processor, the at least one processor being connected to the at least one transceiver, wherein the at least one processor is configured to: receive a request frame related to the initiation of a relay operation targeted at one or more second STAs from an access point AP; send a response frame to the AP for the request frame; receive a physical layer protocol data unit PPDU including data based on the relay operation from the AP; and send the PPDU including the data to the one or more second STAs, wherein the request frame includes ID information for identifying the one or more second STAs as the destination of the relay operation.

19. A method performed by an AP in a wireless local area network system, the method comprising: Sending a request frame related to the initiation of a relay operation targeted at one or more second STAs to a first STA; Receiving a response frame for the request frame from the first STA; And Sending a physical layer protocol data unit (PPDU) including data based on the relay operation to the first STA, Wherein the request frame includes ID information for identifying the one or more second STAs as the destinations of the relay operation.

20. An apparatus for an access point (AP) in a wireless local area network (WLAN) system, the apparatus comprising: At least one transceiver; And At least one processor, the at least one processor being connected to the at least one transceiver, Wherein the at least one processor is configured to: Send a request frame related to the initiation of a relay operation targeted at one or more second STAs to a first STA; Receive a response frame for the request frame from the first STA; and Send a physical layer protocol data unit (PPDU) including data based on the relay operation to the first STA, Wherein the request frame includes ID information for identifying the one or more second STAs as the destinations of the relay operation.

21. A processing unit configured to control a station (STA) in a wireless local area network (WLAN) system, the processing unit comprising: At least one processor; And 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 17 when executed by the at least one processor.

22. At least one non-transitory computer-readable medium storing at least one instruction, wherein The at least one instruction, when executed by at least one processor, controls a device to perform the method according to any one of claims 1 to 17 in a wireless local area network (WLAN) system.

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