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

Abstract

A method and apparatus for transmitting and receiving PPDU in a wireless LAN system are disclosed. A method according to one embodiment of the present disclosure may include: receiving a triggering frame from an AP by a STA; and transmitting a PPDU to the AP by the STA based on the triggering frame.

Description

Technology Field

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

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

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

[0004] The technical problem of the present disclosure is to provide a method and apparatus for transmitting and receiving PPDUs using an unequal modulation (UEQM) technique.

[0005] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below. means of solving the problem

[0006] A method according to one aspect of the present disclosure may include: receiving a triggering frame from an access point (AP) by a station (STA); and transmitting a physical protocol data unit (PPDU) to the AP by the STA based on the triggering frame. The triggering frame may include instruction information indicating whether equal modulation (EQM) or unequal modulation (UEQM) is applied for the transmission of the PPDU.

[0007] A method according to a further aspect of the present disclosure may include: transmitting a triggering frame to a station (STA) by an access point (AP); and receiving a physical protocol data unit (PPDU) from the STA by the AP based on the triggering frame. The triggering frame may include instruction information indicating whether equal modulation (EQM) or unequal modulation (UEQM) is applied for the transmission of the PPDU. Effects of the invention

[0008] According to the present disclosure, efficient transmission is possible by applying UEQM, which applies different modulation orders to each spatial stream during MIMO (multi-input multi-output) / beamforming transmission.

[0009] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below. Brief explanation of the drawing

[0010] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and explain the technical features of the present disclosure together with the detailed description. FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure. FIG. 2 is a drawing showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied. FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied. FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied. FIG. 5 is a diagram illustrating a CSMA / CA-based frame transmission operation to which the present disclosure may be applied. FIG. 6 is a drawing for illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure may be applied. FIG. 7 is a drawing illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure may be applied. FIG. 8 is a drawing for illustrating examples of resource units of a wireless LAN system to which the present disclosure may be applied. FIG. 9 is a drawing for illustrating examples of resource units of a wireless LAN system to which the present disclosure may be applied. FIG. 10 is a drawing for illustrating examples of resource units of a wireless LAN system to which the present disclosure may be applied. Figure 11 shows an exemplary structure of the EHT-SIG content channel. FIG. 12 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied. FIG. 13 is a diagram showing the format of a common information field within a trigger frame to which the present disclosure can be applied. FIG. 14 illustrates a special user information field of a trigger frame to which the present disclosure can be applied. FIG. 15 illustrates the difference in SNR between multiple spatial streams in a wireless communication system to which the present disclosure may be applied. FIG. 16 illustrates a method for indicating UEQM capability according to one embodiment of the present disclosure. FIG. 17 illustrates a TRS control field according to one embodiment of the present disclosure. FIG. 18 illustrates a portion of the common information field of a trigger frame according to one embodiment of the present disclosure. FIG. 19 illustrates a portion of a special user information field of a trigger frame according to one embodiment of the present disclosure. FIG. 20 illustrates a portion of the user information field of a trigger frame according to one embodiment of the present disclosure. FIG. 21 illustrates the operation of an STA device for a PPDU transmission and reception method according to one embodiment of the present disclosure. FIG. 22 illustrates the operation of an AP device for a PPDU transmission and reception method according to one embodiment of the present disclosure. Specific details for implementing the invention

[0011] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below, together with the accompanying drawings, is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure may be practiced. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the art will know that the present disclosure may be practiced without such specific details.

[0012] In some cases, to avoid obscuring the concept of the present disclosure, known structures and devices may be omitted or illustrated in the form of a block diagram focusing on the core functions of each structure and device.

[0013] In the present disclosure, when a component is described as being “connected,” “combined,” or “joined” with another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, in the present disclosure, the terms “comprising” or “having” specify the presence of the mentioned features, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, actions, elements, components, and / or groups thereof.

[0014] In the present disclosure, terms such as "first," "second," etc. are used solely for the purpose of distinguishing one component from another and are not used to limit the components, nor do they limit the order or importance of the components unless specifically stated otherwise. Accordingly, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and likewise, a second component in one embodiment may be referred to as a first component in another embodiment.

[0015] The terms used in this disclosure are for the description of specific embodiments and are not intended to limit the claims. As used in the description of embodiments and in the appended claims, the singular form is intended to include the plural form unless the context clearly indicates otherwise. The term "and / or" as used in this disclosure may refer to any one of the related enumerated items, or refers to and includes any and all possible combinations of two or more of them. Additionally, the " / " between words in this disclosure has the same meaning as "and / or" unless otherwise noted.

[0016] The embodiments of the present disclosure may be applied to various wireless communication systems. For example, the embodiments of the present disclosure may be applied to wireless LAN systems. For example, the embodiments of the present disclosure may be applied to wireless LANs based on IEEE 802.11a / g / n / ac / ax / be standards. Furthermore, the embodiments of the present disclosure may be applied to wireless LANs based on newly proposed IEEE 802.11bn (or UHR) standards. Additionally, the embodiments of the present disclosure may be applied to wireless LANs based on next-generation standards following IEEE 802.11bn. Furthermore, the embodiments of the present disclosure may be applied to cellular wireless communication systems. For example, they may be applied to cellular wireless communication systems based on LTE (Long Term Evolution) series technologies and 5G NR (New Radio) series technologies of 3GPP (3rd Generation Partnership Project) standards.

[0017] The following describes the technical features to which the examples of the present disclosure may be applied.

[0018] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0019] The first device (100) and the second device (200) exemplified in FIG. 1 may be replaced with various terms such as terminal, wireless device, WTRU (Wireless Transmit Receive Unit), UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), MSS (Mobile Subscriber Unit), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), or simply user. Additionally, the first device (100) and the second device (200) may be replaced with various terms such as access point (AP), BS (Base Station), fixed station, Node B, BTS (base transceiver system), network, AI (Artificial Intelligence) system, RSU (road side unit), repeater, router, relay, gateway, etc.

[0020] The device (100, 200) exemplified in FIG. 1 may be referred to as a station (STA). For example, the device (100, 200) exemplified in FIG. 1 may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, or a receiving STA. For example, the STA (110, 200) may perform the role of an access point (AP) or a non-AP. That is, in the present disclosure, the STA (110, 200) may perform the functions of an AP and / or a non-AP. If the STA (110, 200) performs the AP function, it may simply be referred to as an AP, and if the STA (110, 200) performs the non-AP function, it may simply be referred to as a STA. Additionally, in the present disclosure, the AP may also be indicated as an AP STA.

[0021] Referring to FIG. 1, the first device (100) and the second device (200) can transmit and receive wireless signals through various wireless LAN technologies (e.g., IEEE 802.11 series). The first device (100) and the second device (200) may include interfaces for the medium access control (MAC) layer and the physical layer (PHY) that comply with the specifications of the IEEE 802.11 standard.

[0022] In addition, the first device (100) and the second device (200) may additionally support various communication standards other than wireless LAN technology (e.g., 3GPP LTE series, 5G NR series standards, etc.). In addition, the device of the present disclosure may be implemented as various devices such as mobile phones, vehicles, personal computers, AR (Augmented Reality) equipment, VR (Virtual Reality) equipment, etc. Furthermore, the STA of the present specification may support various communication services such as voice calls, video calls, data communication, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).

[0023] The first device (100) includes one or more processors (102) and one or more memories (104), and may additionally include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memory (104) and / or transceivers (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (102) may process information within the memory (104) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through the transceiver (106) and then store information obtained from the signal processing of the second information / signal in the memory (104). Memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, memory (104) may store software code including instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this disclosure. Here, the processor (102) and memory (104) may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals through one or more antennas (108). The transceiver (106) may include a transmitter and / or receiver. The transceiver (106) may be combined with an RF (Radio Frequency) unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0024] The second device (200) includes one or more processors (202) and one or more memories (204), and may additionally include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memory (204) and / or transceivers (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this disclosure. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be used in combination with an RF unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0025] Hereinafter, hardware elements of the device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure. One or more processors (102, 202) may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this disclosure and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., a baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this disclosure.

[0026] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0027] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0028] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of the present disclosure to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., disclosed in the present disclosure from one or more other devices. For example, one or more transceivers (106, 206) may be connected to one or more processors (102, 202) and may transmit and receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure through one or more antennas (108, 208). In this disclosure, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0029] For example, one of the STAs (100, 200) may perform the intended operation of an AP, and the other of the STAs (100, 200) may perform the intended operation of a non-AP STA. For example, the transceiver (106, 206) of FIG. 1 may perform the operation of transmitting and receiving signals (e.g., packets or PPDU (Physical Layer Protocol Data Unit) according to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). Additionally, the operation of generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals by various STAs in the present disclosure may be performed by the processor (102, 202) of FIG. 1. For example, an example of an operation to generate a transmission and reception signal or to perform data processing or operations in advance for a transmission and reception signal may include: 1) an operation to determine / acquire / configure / operate / decode / encode bit information of fields (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in the PPDU; 2) an operation to determine / configure / acquire time resources or frequency resources (e.g., subcarrier resources) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 3) an operation to determine / configure / acquire specific sequences (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 4) power control operations and / or power saving operations applied to the STA; and 5) operations related to determining / acquiring / configuring / operating / decoding / encoding of an ACK signal. In addition, in the following example, various information (e.g., information related to fields, subfields, control fields, parameters, power, etc.) used by various STAs for determining / acquiring / configuring / calculating / decoding / encoding of transmission and reception signals can be stored in the memory (104, 204) of FIG. 1.

[0030] In the following, the downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs, packets, signals, etc., can be transmitted and received through the downlink. In downlink communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. The uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs, packets, signals, etc., can be transmitted and received through the uplink. In uplink communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

[0031] FIG. 2 is a drawing showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0032] The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports STA mobility transparent to the upper layer can be provided. A Basic Service Set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 exemplarily illustrates the existence of two BSSs (BSS1 and BSS2) and the inclusion of two STAs as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). In Figure 2, the ellipse representing the BSS can also be understood as representing the coverage area where the STAs included in the corresponding BSS maintain communication. This area can be referred to as a Basic Service Area (BSA). If a STA moves outside the BSA, it becomes unable to communicate directly with other STAs within that BSA.

[0033] Excluding the DS illustrated in Fig. 2, the most basic type of BSS in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For instance, assuming other components are omitted, a BSS1 composed of only STA1 and STA2, or a BSS2 composed of only STA3 and STA4, can each be considered a representative example of an IBSS. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, this type of wireless LAN is not configured through pre-planning but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. In other words, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and since connections to distributed systems (DS) are not allowed, they form a self-contained network.

[0034] The membership of an STA in a BSS can be dynamically changed by the STA being turned on or off, or by the STA entering or leaving the BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, an STA must be associated with the BSS. This association can be configured dynamically and may include the use of a Distribution System Service (DSS).

[0035] In a wireless LAN, the direct STA-to-STA distance may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in others, communication between STAs over longer distances may be required. To support extended coverage, a distributed system (DS) may be configured.

[0036] DS refers to a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component in an extended form of a network composed of multiple BSSs. DS is a logical concept and can be specified by the characteristics of the Distributed System Medium (DSM). In this regard, the Wireless Medium (WM) and the DSM can be logically distinguished. Each logical medium is used for a different purpose and is utilized by different components. These media are not limited to being identical or different. The flexibility of the wireless LAN structure (DS structure or other network structure) can be explained by the fact that multiple media are logically distinct in this way. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be specified independently by the physical characteristics of each implementation.

[0037] DS can support mobile devices by providing seamless integration of multiple BSSs and providing logical services necessary for handling addresses to destinations. Additionally, DS may include a component called a portal that acts as a bridge for connecting the wireless LAN with another network (e.g., IEEE 802.X).

[0038] An AP refers to an entity that enables access to a DS via a WM for combined non-AP STAs and also possesses the functionality of an STA. Data movement between a BSS and a DS can be performed through the AP. For example, STA2 and STA3 shown in FIG. 2 possess the functionality of an STA and provide the ability for combined non-AP STAs (STA1 and STA4) to access a DS. Furthermore, since all APs fundamentally correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM and the address used by the AP for communication on the DSM do not necessarily have to be the same. A BSS composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0039] Data transmitted from one of the STA(s) coupled to the AP to the STA address of the AP can always be received at an uncontrolled port and processed by an IEEE 802.1X port access entity. Additionally, if the controlled port is authenticated, the transmitted data (or frame) can be forwarded to the DS.

[0040] In addition to the structure of the aforementioned DS, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0041] An ESS refers to a network of arbitrary size and complexity composed of DSs and BSSs. An ESS can correspond to a set of BSSs connected to a single DS. However, an ESS does not contain a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in a single ESS can have the same Service Set Identification (SSID). The SSID is distinct from the BSSID, which is the identifier for the BSS.

[0042] In wireless LAN systems, no assumptions are made regarding the relative physical locations of BSSs, and all of the following forms are possible. BSSs may partially overlap, which is a form commonly used to provide continuous coverage. Additionally, BSSs may not be physically connected, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs may be located in the same physical location, which can be used to provide redundancy. Also, one (or more) IBSS or ESS networks may physically exist in the same space as one (or more) ESS networks. This may apply to ESS network forms such as when an ad-hoc network operates at a location where an ESS network exists, when wireless networks that physically overlap are configured by different organizations, or when two or more different access and security policies are required at the same location.

[0043] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0044] In order for an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and go through authentication procedures for security. The link setup process can also be referred to as the session initiation process or the session setup process. Additionally, the processes of discovery, authentication, association, and security setup in the link setup process can be collectively referred to as the association process.

[0045] In step S310, the STA may perform a network discovery operation. The network discovery operation may include the STA's scanning operation. That is, in order for the STA to access a network, it must find a network it can join. Before joining a wireless network, the STA must identify a compatible network, and the process of identifying networks existing in a specific area is called scanning.

[0046] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, the STA performing the scanning moves between channels to search for nearby APs, transmits a probe request frame, and waits for a response. The responder transmits a probe response frame as a response to the probe request frame to the STA that transmitted the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame from the BSS of the channel being scanned. In a BSS, the AP becomes the responder because it transmits the beacon frame; however, in an IBSS, the responder is not constant because STAs within the IBSS take turns transmitting the beacon frame. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning in the same way (i.e., transmit and receive probe request / response on channel 2).

[0047] Although not illustrated in FIG. 3, the scanning operation may be performed using a passive scanning method. In passive scanning, the STA performing the scanning waits for a beacon frame while switching between channels. A beacon frame is one of the management frames defined in IEEE 802.11, which is periodically transmitted to announce the presence of a wireless network and to allow the scanning STA to find the wireless network and join it. In a BSS, the AP performs the role of periodically transmitting beacon frames, and in an IBSS, the STAs within the IBSS take turns transmitting beacon frames. When the scanning STA receives a beacon frame, it stores the information about the BSS included in the beacon frame and records the beacon frame information in each channel while moving to another channel. The STA that receives the beacon frame stores the BSS-related information included in the received beacon frame and moves to the next channel, and can perform scanning in the next channel in the same way. When comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0048] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation in step S340 described later.

[0049] The authentication process involves the STA sending an authentication request frame to the AP, and the AP sending an authentication response frame to the STA in response. The authentication frame used in the authentication request / response corresponds to a management frame.

[0050] The authentication frame may include information regarding the authentication algorithm number, authentication transaction sequence number, status code, challenge text, Robust Security Network (RSN), Finite Cyclic Group, etc. These are some examples of information that may be included in the authentication request / response frame, and they may be replaced with other information or additional information may be included.

[0051] The STA can send an authentication request frame to the AP. Based on the information contained in the received authentication request frame, the AP can determine whether to allow authentication for the STA. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0052] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the STA transmitting an association request frame to the AP, and in response, the AP transmitting an association response frame to the STA.

[0053] For example, the association request frame may include information regarding various capabilities, beacon listen interval, service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information regarding various capabilities, status code, Association ID (AID), supported rates, Enhanced Distributed Channel Access (EDCA) parameter set, Received Channel Power Indicator (RCPI), Received Signal to Noise Indicator (RSNI), mobility domain, timeout interval (e.g., association comeback time), overlapping BSS scan parameters, TIM broadcast response, Quality of Service (QoS) map, etc. This is a partial example of the information that may be included in a combined request / response frame, and it may be replaced with other information or additional information may be included.

[0054] After the STA is successfully joined to the network, a security setup process can be performed in step S340. The security setup process in step S340 may be described as an authentication process through RSNA (Robust Security Network Association) requests / responses, and the authentication process in step S320 may be referred to as the first authentication process, and the security setup process in step S340 may simply be referred to as the authentication process.

[0055] The security setup process of step S340 may include, for example, a private key setup process through a 4-way handshake via an EAPOL (Extensible Authentication Protocol over LAN) frame. Additionally, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

[0056] FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied.

[0057] In wireless LAN systems, the basic access mechanism for MAC (Medium Access Control) is the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism is also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, and it basically employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA may perform Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time interval (e.g., DIFS (DCF Inter-Frame Space)) before starting transmission. If the sensing result determines that the medium is in an idle status, it starts transmitting a frame through that medium. On the other hand, if the medium is detected to be occupied or busy, the AP and / or STA may not start its own transmission but wait by setting a delay period for medium access (e.g., a random backoff period) before attempting to transmit a frame. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

[0058] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). The HCF is based on the aforementioned Point Coordination Function (PCF). The PCF is a polling-based synchronous access method that periodically polls to ensure all receiving APs and / or STAs can receive data frames. Furthermore, the HCF includes Enhanced Distributed Channel Access (EDCA) and Controlled Channel Access (HCCA). EDCA is a contention-based access method for a provider to offer data frames to multiple users, while HCCA uses a non-contention-based channel access method utilizing a polling mechanism. Additionally, the HCF includes a media access mechanism to improve the Quality of Service (QoS) of the wireless LAN and can transmit QoS data during both the Contention Period (CP) and the Contention-Free Period (CFP).

[0059] Referring to FIG. 4, the operation based on the random backoff period is described. When a medium in an occupied / busy state changes to an idle state, multiple STAs may attempt to transmit data (or frames). As a measure to minimize collisions, each STA may select a random backoff count and attempt transmission after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​in the range from 0 to CW. Here, CW is the Contention Window parameter value. The CW parameter is given an initial value of CWmin, but in the case of transmission failure (e.g., failure to receive an ACK for a transmitted frame), it may take a value twice that amount. When the CW parameter value becomes CWmax, data transmission may be attempted while maintaining the CWmax value until data transmission is successful; if data transmission is successful, it is reset to the CWmin value. The values ​​of CW, CWmin, and CWmax are 2 n It is desirable to set it to -1 (n=0, 1, 2, ...).

[0060] When the random backoff process begins, the STA continues to monitor the media while counting down the backoff slots according to the determined backoff count value. When the media is monitored as occupied, it stops the countdown and waits, and when the media becomes idle, it resumes the remaining countdown.

[0061] In the example of Fig. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 confirms that the medium is idle for DIFS and can immediately transmit the frame. The remaining STAs monitor whether the medium is occupied or busy and wait. Meanwhile, data to be transmitted may also arise from each of STA1, STA2, and STA5, and each STA can perform a countdown of the backoff slot according to a random backoff count value selected by each after waiting for DIFS when the medium is monitored to be idle. Assume the case where STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. That is, this exemplifies a case where, at the point when STA2 finishes the backoff count and starts transmitting the frame, the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1. STA1 and STA5 pause the countdown briefly and wait while STA2 occupies the medium. When STA2's possession ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the paused backoff count. That is, they can start transmitting a frame after counting down the remaining backoff slots corresponding to the remaining backoff time. Since STA5's remaining backoff time was shorter than STA1's, STA5 starts transmitting the frame. While STA2 is occupying the medium, data to be transmitted may also be generated by STA4. From STA4's perspective, when the medium becomes idle, it waits for DIFS, performs a countdown based on a random backoff count value selected by itself, and can start transmitting a frame. The example in Figure 4 illustrates a case where STA5's remaining backoff time happens to match STA4's random backoff count value; in this case, a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 receives an ACK, resulting in a failure to transmit data.In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. STA1 waits while the medium is occupied due to transmission by STA4 and STA5, and when the medium becomes idle, it waits for DIFS, and then can start transmitting frames after the remaining backoff time has passed.

[0062] As shown in the example in Fig. 4, a data frame is a frame used for transmitting data that is forwarded to an upper layer, and can be transmitted after a backoff performed after the elapsed time of DIFS from when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information that is not forwarded to an upper layer, and is transmitted after a backoff performed after the elapsed time of an IFS such as DIFS or PIFS (Point coordination function IFS). Subtypes of management frames include Beacon, Association request / response, re-association request / response, probe request / response, and authentication request / response. A control frame is a frame used to control access to the medium. Subtype frames of control frames include RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), NDP Announcement (null data packet announcement), and Trigger. If a control frame is not an acknowledgment frame of a previous frame, it is transmitted after a backoff performed after the elapsed DIFS; if it is an acknowledgment frame of a previous frame, it is transmitted after the elapsed SIFS (short IFS) without a backoff. The type and subtype of a frame can be identified by the type field and subtype field within the Frame Control (FC) field.

[0063] A QoS (Quality of Service) STA can transmit a frame after backoff, which is performed after the passage of the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC). Here, the frame for which AIFS[i] can be used can be a data frame or a management frame, and can also be a control frame rather than a response frame.

[0064] FIG. 5 is a diagram illustrating a CSMA / CA-based frame transmission operation to which the present disclosure may be applied.

[0065] As previously mentioned, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, where the STA directly senses the medium. Virtual carrier sensing is intended to mitigate problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the STA's MAC can utilize the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available, provided that the STA currently using or authorized to use the medium is using it. Therefore, the value set as the NAV corresponds to the period during which the medium is scheduled to be used by the STA transmitting the frame, and the STA receiving the NAV value is prohibited from accessing the medium during that period. For example, the NAV can be set based on the value of the "duration" field in the frame's MAC header.

[0066] In the example of FIG. 5, it is assumed that STA1 intends to transmit data to STA2, and STA3 is located in a position where it can overhear part or all of the frames transmitted and received between STA1 and STA2.

[0067] In order to reduce the possibility of collisions between multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism utilizing RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA1 may be a hidden node to STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA2 may be a hidden node to STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, it is possible to prevent a STA outside the transmission range of either STA1 or STA2, or a STA outside the carrier sensing range for transmission from STA1 or STA3, from attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0068] Specifically, STA1 can determine whether the channel is in use through carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy magnitude or signal correlation detected in the channel. Additionally, in terms of virtual carrier sensing, STA1 can determine the channel occupancy state using a NAV (network allocation vector) timer.

[0069] If the channel is idle during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. If STA2 receives the RTS frame, it can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0070] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) using the duration information included in the RTS frame. Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + data frame + SIFS + ACK frame) using the duration information included in the CTS frame. That is, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, it can set a NAV accordingly. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0071] If STA1 receives a CTS frame from STA2, it may transmit a data frame to STA2 after SIFS from the time the reception of the CTS frame is completed. If STA2 successfully receives the data frame, it may transmit an ACK frame to STA1 as an acknowledgment to the data frame after SIFS. STA3 may determine whether the channel is in use through carrier sensing when the NAV timer expires. If STA3 determines that the channel is not in use by another terminal during DIFS from the time the NAV timer expires, it may attempt channel access after a contention window (CW) based on random backoff has passed.

[0072] FIG. 6 is a drawing for illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure may be applied.

[0073] Based on instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MPDU (MAC PDU) to be transmitted. For example, upon receiving an instruction from the MAC layer requesting the start of transmission, the PHY layer switches to transmit mode and can construct the information provided by the MAC layer (e.g., data) into a frame for transmission. Additionally, if the PHY layer detects a valid preamble of a received frame, it monitors the preamble header and sends an instruction to the MAC layer indicating the start of reception.

[0074] As such, information transmission and reception in wireless LAN systems are carried out in the form of frames, and for this purpose, the Physical Layer Protocol Data Unit (PPDU) format is defined.

[0075] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIGNAL) field, and a Data field. The most basic (e.g., the non-HT (High Throughput)) PPDU format illustrated in FIG. 7 may consist only of Legacy-STF (Legacy-STF), Legacy-LTF (Legacy-LTF), Legacy-SIG (Legacy-SIG) fields and a Data field. In addition, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or other types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF, (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the data field. More specific details will be described later with reference to FIG. 7.

[0076] STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, and precise time synchronization, while LTF is a signal for channel estimation and frequency error estimation. STF and LTF can be considered signals for synchronization and channel estimation in the OFDM physical layer.

[0077] The SIG field may contain various information related to the transmission and reception of the PPDU. For example, the L-SIG field consists of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may contain information regarding the modulation and coding rates of the data. For example, the 12-bit Length field may contain information regarding the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of the PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDUs, the value of the Length field may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0078] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), and PPDU TAIL bits, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiver. The PSDU corresponds to a MAC PDU defined at the MAC layer and may contain data generated or used by the upper layer. The PPDU TAIL bits may be used to return the encoder to a 0 state. Padding bits may be used to adjust the length of the data field to a predetermined unit.

[0079] A MAC PDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). A MAC frame is composed of a MAC PDU and can be transmitted or received through the PSDU of the data portion in the PPDU format.

[0080] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may contain control information necessary for transmitting or receiving frames. The Duration / ID field may be set as the time for transmitting the corresponding frame. Address subfields may indicate the frame's receiver address, transmitter address, destination address, and source address, and some address subfields may be omitted. Specific details regarding each subfield of the MAC header, including Sequence Control, QoS Control, and HT Control subfields, can be found in the IEEE 802.11 standard document.

[0081] The Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP is a frame format that includes the PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and additionally, non-legacy SIG, non-legacy STF, and non-legacy LTF if present) from a standard PPDU format, but excludes the remaining parts (i.e., the data field).

[0082] FIG. 7 is a drawing illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure may be applied.

[0083] Various forms of PPDU have been used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format may also be referred to as the non-HT PPDU format (Fig. 7(a)).

[0084] The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format illustrated in FIG. 7(b) may be referred to as the HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field, without including L-STF, L-LTF, and L-SIG (not shown).

[0085] An example of the VHT PPDU format (IEEE 802.11ac) includes the VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).

[0086] An example of the HE PPDU format (IEEE 802.11ax) includes the RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in addition to the basic PPDU format (Fig. 7(d)). Depending on the specific examples of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multiple users (MU), but is not included in the HE PPDU format for single users (SU). Additionally, the HE trigger-based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field may vary to 8 µs. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16 µs. For example, RL-SIG can be configured identically to L-SIG. Based on the presence of RL-SIG, the receiving STA can determine that the received PPDU is a HE PPDU or the EHT PPDU described later.

[0087] The EHT PPDU format may include the EHT MU (multi-user) of FIG. 7(e) and the EHT TB (trigger-based) PPDU of FIG. 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes RL-SIG following L-SIG, but it may include U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following RL-SIG.

[0088] The EHT MU PPDU of FIG. 7(e) corresponds to a PPDU that carries one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0089] The EHT-SIG is omitted in the EHT TB PPDU of FIG. 7(f) compared to the EHT MU PPDU. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0090] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated so that demodulation and decoding can be attempted even on legacy STAs, and mapped based on a defined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated so that they can be demodulated and decoded by a STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) to obtain the information contained in the corresponding fields, and mapped based on a defined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0091] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulation fields. Also, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as pre-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0092] The U-SIG included in the EHT PPDU format of FIG. 7 can be constructed based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol for the U-SIG (e.g., OFDM symbol) can have a duration of 4 µs, and the U-SIG can have a total duration of 8 µs. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0093] U-SIGs can be configured in 20 MHz units. For example, if an 80 MHz PPDU is configured, the same U-SIG can be duplicated in 20 MHz units. That is, four identical U-SIGs can be included within an 80 MHz PPDU. If the bandwidth exceeds 80 MHz, for example, for a 160 MHz PPDU, the U-SIG of the first 80 MHz unit and the U-SIG of the second 80 MHz unit may be different.

[0094] For example, A number of uncoded bits may be transmitted through U-SIG, and the first symbol of U-SIG (e.g., U-SIG-1 symbol) transmits the first X bits of the total A bit information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) transmits the remaining Y bits of the total A bit information. The A bit information (e.g., 52 uncoded bits) may include a CRC field (e.g., a field of 4 bits) and a tail field (e.g., a field of 6 bits). The tail field may be used to terminate the trellis of the convolution decoder and may be set to, for example, 0.

[0095] A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG may be included in a new PPDU format not shown in FIG. 7 (e.g., UHR PPDU format), and in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, and some or all of the version-dependent bits may be different.

[0096] For example, the size of the version-independent bits of U-SIG can be fixed or variable. The version-independent bits may be assigned only to U-SIG-1 symbols or to both U-SIG-1 and U-SIG-2 symbols. The version-independent bits and version-dependent bits may be referred to by various names, such as the first control bit and the second control bit.

[0097] For example, the version-independent bits of U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version of the transmitted / received PPDU (e.g., EHT, UHR, etc.). The version-independent bits of U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value of the UL / DL flag field relates to DL communication. The version-independent bits of U-SIG may include information regarding the length of the TXOP (transmission opportunity) and information regarding the BSS color ID.

[0098] For example, the version-dependent bits of U-SIG may contain information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0099] Information necessary for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information regarding bandwidth, information regarding MCS techniques applied to non-legacy SIGs (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether DCM (dual carrier modulation) techniques (e.g., techniques to achieve an effect similar to frequency diversity by reusing the same signal on two subcarriers) are applied to non-legacy SIGs, information regarding the number of symbols used for non-legacy SIGs, and information regarding whether non-legacy SIGs are generated across the entire band.

[0100] Some of the information required for PPDU transmission and reception may be included in U-SIG and / or non-legacy SIGs (e.g., EHT-SIG or UHR-SIG, etc.). For example, information regarding the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information regarding the length of non-legacy LTF and cyclic prefix (CP) length, information regarding guard interval (GI) applied to non-legacy LTF, information regarding preamble puncturing applicable to PPDU, information regarding resource unit (RU) allocation, etc., may be included only in U-SIG, may be included only in non-legacy SIG, or may be indicated by a combination of information included in U-SIG and information included in non-legacy SIG.

[0101] Preamble puncturing may refer to the transmission of a PPDU in which a signal is not present in one or more frequency units within the PPDU bandwidth. For example, the size of the frequency unit (or the resolution of preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or larger.

[0102] In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. A non-legacy SIG may be transmitted through at least one symbol, and one symbol may have a length of 4 µs. Information regarding the number of symbols used for EHT-SIG may be included in the previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0103] Non-legacy SIGs, such as HE-SIG-B and EHT-SIG, may include common fields and user-specific fields. Common fields and user-specific fields may be coded individually.

[0104] In some cases, the common field may be omitted. For example, in a compression mode where non-OFDMA (orthogonal frequency multiple access) is applied, the common field may be omitted, and multiple STAs may receive PPDUs (e.g., the data field of the PPDU) over the same frequency band. In a non-compression mode where OFDMA is applied, multiple users may receive PPDUs (e.g., the data field of the PPDU) over different frequency bands.

[0105] The number of user-specific fields can be determined based on the number of users. A single user block field can contain up to two user fields. Each user field may be related to MU-MIMO allocation or non-MU-MIMO allocation.

[0106] The common field may include CRC bits and Tail bits, the length of the CRC bits may be determined to be 4 bits, and the length of the Tail bits may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information regarding the location of the RU to which a plurality of users (i.e., a plurality of receiving STAs) are allocated.

[0107] An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on the OFDMA technique. Additionally, an RU may be defined when transmitting signals to a single STA. Resources may be allocated on an RU basis for non-legacy STF, non-legacy LTF, and Data fields.

[0108] Applicable RU sizes can be defined according to the PPDU bandwidth. RUs may be defined identically or differently for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU placement for HE PPDU and EHT PPDU may differ. The applicable RU sizes, number of RUs, RU locations, DC (direct current) subcarrier locations and numbers, null subcarrier locations and numbers, and guard subcarrier locations and numbers for each PPDU bandwidth can be referred to as a tone-plan. For example, a tone-plan for a wide bandwidth may be defined as a multiple repetition of a tone-plan for a low bandwidth.

[0109] RUs of various sizes can be defined as 26-ton RUs, 52-ton RUs, 106-ton RUs, 242-ton RUs, 484-ton RUs, 996-ton RUs, 2x996-ton RUs, 3x996-ton RUs, etc. An MRU (multiple RU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers composed of multiple RUs. For example, one MRU can be defined as 52+26-tons, 106+26-tons, 484+242-tons, 996+484-tons, 996+484+242-tons, 2x996+484-tons, 3x996-tons, or 3x996+484-tons. In addition, multiple RUs constituting a single MRU may be continuous or non-continuous in the frequency domain.

[0110] The specific size of the RU may be reduced or expanded. Accordingly, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not limited and is exemplary. Additionally, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) in this disclosure, the number of RUs may vary depending on the RU size.

[0111] The names of the respective fields in the PPDU formats of FIG. 7 are exemplary and the scope of the present disclosure is not limited by such names. Furthermore, the examples of the present disclosure may be applied not only to the PPDU formats exemplified in FIG. 7, but also to new PPDU formats based on the PPDU formats of FIG. 7 in which some fields are excluded and / or some fields are added.

[0112] Resource Units (RU) and Resource Allocation

[0113] FIGS. 8 to 10 are drawings for illustrating examples of resource units of a wireless LAN system to which the present disclosure may be applied.

[0114] With reference to FIGS. 8 to 10, a resource unit (RU) defined in a wireless LAN system will be described. The RU may include multiple subcarriers (or tones). The RU may be used when transmitting signals to multiple STAs based on the OFDMA technique. Additionally, the RU may be defined when transmitting signals to a single STA. The RU may be used for the STF, LTF, data fields, etc., of a PPDU.

[0115] As illustrated in FIGS. 8 to 10, RUs corresponding to different numbers of tones (i.e., subcarriers) can be used to form some fields of a 20 MHz, 40 MHz, or 80 MHz X-PPDU (X is HE, EHT, etc.). For example, resources can be allocated in units of the illustrated RUs for the X-STF, X-LTF, and Data fields.

[0116] FIG. 8 is a diagram showing an exemplary arrangement of resource units (RU) used in the 20 MHz band.

[0117] As shown at the top of FIG. 8, 26 units (i.e., units corresponding to 26 tones) may be allocated. Six tones may be used as a guard band in the leftmost band of the 20 MHz band, and five tones may be used as a guard band in the rightmost band of the 20 MHz band. Additionally, seven DC tones may be inserted in the center band, i.e., the DC band, and 26 units corresponding to 13 tones may exist on the left and right sides of the DC band. Furthermore, 26, 52, and 106 units may be allocated to other bands. Each unit may be allocated for an STA or a user.

[0118] The RU arrangement of FIG. 8 is utilized not only for situations involving multiple users (MU) but also for situations involving a single user (SU), in which case it is possible to use one 242-unit as shown at the bottom of FIG. 8. In this case, three DC tones can be inserted.

[0119] In the example of FIG. 8, various sizes of RUs, namely 26-RU, 52-RU, 106-RU, 242-RU, etc., are exemplified, but the specific size of these RUs may be reduced or expanded. Accordingly, in the present disclosure, the specific size of each RU (i.e., the number of corresponding tones) is not limited and is exemplary. Furthermore, in the present disclosure, within a predetermined bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...), the number of RUs may vary depending on the RU size. In the example of FIG. 9 and / or FIG. 10 described below, the size and / or number of RUs may be changed, which is the same as in the example of FIG. 8.

[0120] FIG. 9 is a diagram showing an exemplary arrangement of resource units (RU) used in the 40 MHz band.

[0121] Just as various sizes of RUs were used in the example of FIG. 8, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc., may also be used in the example of FIG. 9. Additionally, 5 DC tones may be inserted at the center frequency, 12 tones may be used as guard bands in the leftmost band of the 40 MHz band, and 11 tones may be used as guard bands in the rightmost band of the 40 MHz band.

[0122] In addition, as described, when used for a single user, the 484-RU can be used.

[0123] FIG. 10 is a diagram showing an exemplary arrangement of resource units (RU) used in the 80 MHz band.

[0124] Just as various sizes of RUs were used in the examples of FIGS. 8 and 9, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc., may also be used in the example of FIG. 10. Additionally, in the case of an 80MHz PPDU, the RU arrangement of the HE PPDU and the EHT PPDU may differ, and the example of FIG. 10 shows an example of the RU arrangement for an 80MHz EHT PPDU. In the example of FIG. 10, 12 tones are used as guard bands in the leftmost band of the 80MHz band, and 11 tones are used as guard bands in the rightmost band of the 80MHz band, which is the same for the HE PPDU and the EHT PPDU. Unlike the HE PPDU, where 7 DC tones are inserted into the DC band and there is one 26-RU corresponding to 13 tones on each side of the DC band, the EHT PPDU has 23 DC tones inserted into the DC band and one 26-RU on each side of the DC band. Unlike the HE PPDU, where there is one null subcarrier between 242-RUs outside the center band, there are 5 null subcarriers in the EHT PPDU. In the HE PPDU, one 484-RU does not contain a null subcarrier, but in the EHT PPDU, one 484-RU contains 5 null subcarriers.

[0125] In addition, as described, when used for a single user, the 996-RU can be used, and in this case, the insertion of 5 DC tones is common to both the HE PPDU and the EHT PPDU.

[0126] EHT PPDUs of 160 MHz or higher can be configured as multiple 80 MHz subblocks of FIG. 10. The RU arrangement for each 80 MHz subblock may be the same as the RU arrangement of the 80 MHz EHT PPDU of FIG. 10. When the 80 MHz subblock of a 160 MHz or 320 MHz EHT PPDU is not punctured and the entire 80 MHz subblock is used as part of an RU or MRU (Multiple RU), the 80 MHz subblock may use the 996-RU of FIG. 10.

[0127] Here, an MRU corresponds to a group of subcarriers (or tons) composed of multiple RUs, wherein the multiple RUs constituting the MRU may be RUs of the same size or RUs of different sizes. For example, a single MRU may be defined as 52+26-tons, 106+26-tons, 484+242-tons, 996+484-tons, 996+484+242-tons, 2×996+484-tons, 3×996-tons, or 3×996+484-tons. Here, the multiple RUs constituting a single MRU may correspond to RUs of small size (e.g., 26, 52, 106) or RUs of large size (e.g., 242, 484, 996, etc.). That is, a single MRU containing both small-size RUs and large-size RUs may not be set / defined. In addition, multiple RUs constituting a single MRU may be continuous or non-continuous in the frequency domain.

[0128] If the 80 MHz subblock contains RUs smaller than 996 ton, or if parts of the 80 MHz subblock are punctured, the 80 MHz subblock may use RU batches excluding the 996-ton RU.

[0129] The positions of the RUs can be fixed according to their respective PPDU bandwidths as defined in Tables 1 to 5 below.

[0130] Table 1 illustrates the indices of the RUs within the 20 MHz PPDU, the data for each RU, and the pilot subcarrier indices (ranges).

[0131]

[0132] Table 2 illustrates the indices of the RUs within the 40 MHz PPDU, the data for each RU, and the pilot subcarrier indices (ranges).

[0133]

[0134] Table 3 illustrates the indices of the RUs within the 80MHz PPDU, the data for each RU, and the pilot subcarrier indices (ranges).

[0135]

[0136] Table 4 illustrates the indices of the RUs within the 160 MHz PPDU, the data for each RU, and the pilot subcarrier indices (ranges).

[0137]

[0138]

[0139] Table 5 illustrates the indices of the RUs within the 320 MHz PPDU, the data for each RU, and the pilot subcarrier indices (ranges).

[0140]

[0141]

[0142]

[0143]

[0144] In Table 1, RU 5 corresponds to a middle 26-ton RU.

[0145] Referring to Tables 1 through 5, subcarrier index 0 corresponds to the DC tone. Negative subcarrier indices correspond to subcarriers having frequencies lower than the DC tone. Positive subcarrier indices correspond to subcarriers having frequencies higher than the DC tone. DC subcarriers may refer to subcarriers having zero energy that include the DC tone and subcarrier indices adjacent to subcarrier index 0 (i.e., the DC tone). Guard subcarriers may refer to subcarriers having zero energy that are located at the edge of an OFDM symbol in the frequency domain. Null subcarriers are located near the DC or edge tone to protect against transmission center frequency leakage, receiver DC offset, and interference from adjacent RU(s) or MRU(s), and have zero energy.

[0146] Referring to FIGS. 8 to 10 and Tables 1 to 5, for each RU, RU indices can be assigned in order from low frequency to high frequency.

[0147] PPDUs in the range of 160 MHz or higher may be composed of multiple 80 MHz frequency subblocks. The tone plan and RU allocation for each 80 MHz frequency subblock may be the same as those of the 80 MHz PPDU. If the 80 MHz frequency subblock of a 160 MHz or 320 MHz PPDU is not punctured and the entire 80 MHz frequency subblock is used as an RU or as part of an RU / MRU, the 80 MHz frequency subblock may use the 996-tone RU exemplified in FIG. 9. If the 80 MHz frequency subblock contains fewer than 996 tones of RU, or if part of the 80 MHz frequency subblock is punctured, the 80 MHz frequency subblock may use a tone plan and RU allocation excluding the 996-tone RU as exemplified in FIG. 9.

[0148] Multiple RUs (MRU) can be assigned to an STA. The subcarrier indexes of an MRU can be composed of the indexes of the corresponding RUs that make up the MRU.

[0149] The RU of the present disclosure may be used for uplink (UL) and / or downlink (DL) communication. For example, when trigger-based UL-MU communication is performed, the STA transmitting the trigger (e.g., AP) may assign a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a first STA and assign a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a second STA through trigger information (e.g., a trigger frame or TRS (triggered response scheduling)). Subsequently, the first STA may transmit a first trigger-based (TB) PPDU based on the first RU, and the second STA may transmit a second TB PPDU based on the second RU. The first and second TB PPDUs may be transmitted to the AP in the same time interval.

[0150] For example, when a DL MU PPDU is configured, the STA (e.g., AP) transmitting the DL MU PPDU may allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the second STA.

[0151] EHT-SIG field

[0152] The EHT-SIG field of a 20 MHz EHT MU PPDU contains one EHT-SIG content channel. For OFDMA transmission and non-OFDMA transmission for multiple users, the EHT-SIG field of an EHT MU PPDU that is 40 MHz or 80 MHz contains two EHT-SIG content channels. For OFDMA transmission and non-OFDMA transmission for multiple users, the EHT-SIG field of an EHT MU PPDU that is 160 MHz or higher contains two EHT-SIG content channels per 80 MHz frequency subblock. When the EHT MU PPDU bandwidth for OFDMA transmission is wider than 80 MHz, the EHT-SIG content channel per 80 MHz frequency subblock may carry other information.

[0153] Figure 11 shows an exemplary structure of the EHT-SIG content channel.

[0154] Figure 11 illustrates an EHT-SIG content channel format for OFDMA transmission when the bandwidth is 20 / 40 / 80 MHz.

[0155] As shown in Fig. 11, each EHT-SIG content channel can be composed of common fields and user-specific fields.

[0156] Here, the common field may include one or two RU allocation subfields depending on the PPDU frequency bandwidth.

[0157] In the case of OFDMA transmission, the common field of the EHT-SIG content channel may contain information regarding RU allocation, such as the RU allocation to be used in the EHT modulation field of the PPDU, the RUs allocated to MU-MIMO, and the number of users in the MU-MIMO allocation. When the bandwidth is 20 / 30 / 80 MHz, the common field may be composed of one common encoding block, and the common encoding block may contain one or two RU allocation-A subfields. When the bandwidth is 160 MHz, the common field may be composed of two common encoding blocks, the first common encoding block may contain two RU allocation-A subfields, and the second common encoding block may contain two RU allocation-B subfields. When the bandwidth is 320 MHz, the common field may be composed of two common encoding blocks, the first common encoding block may contain two RU allocation-A subfields, and the second common encoding block may contain six RU allocation-B subfields.

[0158] In non-OFDMA transmission, the common field of the EHT-SIG content channel may not include the RU allocation subfield.

[0159] Each RU Assignment-A subfield of the EHT-SIG content channel corresponding to the 20 MHz frequency subchannel may indicate RU or MRU assignments, including the size of the RU(s) / MRU(s) and their placement in the frequency domain. Each RU Assignment-A subfield may also indicate information necessary to calculate the number of users assigned to each RU(s) / MRU(s).

[0160] Each RU Assignment-B subfield of the EHT-SIG content channel corresponding to the 20 MHz frequency subchannel may indicate RU or MRU assignments, including the size of the RU(s) / MRU(s) and their placement in the frequency domain. Each RU Assignment-B subfield may also indicate information necessary to calculate the number of users assigned to each RU(s) / MRU(s).

[0161] The RU allocation-A subfield and the RU allocation-B subfield can both be referred to as RU allocation subfields located in different common encoding blocks.

[0162] For OFDMA transmissions wider than 80 MHz, the RU allocation subfield per 80 MHz frequency subblock can convey consistent RU or MRU size and placement information for the entire PPDU.

[0163] Table 6 illustrates the number of user fields per RU or MRU associated with user-specific fields within the EHT SIG content channel, which are the same as the mapping from the 9-bit RU allocation subfield to the RU allocation.

[0164]

[0165]

[0166]

[0167]

[0168]

[0169] Referring to Table 6, for RU allocation subfields with a value of 64 or greater, y2y1y0 = 000-111 indicates the number of user fields within the EHT-SIG content channel containing the corresponding 9-bit RU allocation subfield. The binary vector y2y1y0 represents N within the EHT-SIG content channel containing the corresponding 9-bit RU allocation subfield. user (r,c)=2 2 × y² + 21 × y1 + y0 + 1 indicates a user field.

[0170] In Table 6, the Number of Entries column may refer to the number of RU assignment subfield values ​​that reference the same RU assignment used in the frequency domain. However, due to different RU assignment subfield values, different numbers of user fields may be included in the user-specific fields of the EHT-SIG content channel that are identical to this RU assignment subfield.

[0171] In Table 6, if there is a value designated as disregard in the RU allocation subfield, the STA is N indicated by the subfield value. user You can skip (r,c) user fields and continue processing the EHT-SIG field.

[0172] Table 7 illustrates the RUs or MRUs associated with each RU allocation subfield for each EHT-SIG content channel and PPDU bandwidth.

[0173]

[0174]

[0175] Table 8 shows the indices of null subcarriers for each RU size when the channel bandwidth is 20 MHz and 40 MHz.

[0176]

[0177] Table 9 shows the indices of null subcarriers for each RU size when the channel bandwidth is 80 MHz, 160 MHz, and 320 MHz.

[0178]

[0179] The number of user-specific fields can be determined based on the number of users. User-specific fields of the EHT-SIG field may be composed of zero or more user encoding blocks. Each user encoding block may be composed of up to two user fields, including a cyclic redundancy code (CRC) and a tail. Additionally, each user field may be related to MU-MIMO allocation or non-MU-MIMO allocation.

[0180] In the case of DL OFDMA transmission (i.e., within the U-SIG field, the UL / DL field is set to 0 and the PPDU Type and Compression Mode field is set to 0), the number of user fields is indicated by the RU Allocation subfield. Each non-final user encoding block consists of two user fields containing information about the two STAs used to decode the payload. The final user encoding block contains information about one or two users, depending on the number of user fields in the EHT-SIG content channel.

[0181] For EHT SU transmission (where the UL / DL field in the U-SIG field is set to 0 or 1, the PPDU Type and Compression Mode field is set to 1, and the EHT-SIG MCS field and the EHT-SIG Symbol Count field are not simultaneously set to 0) and for DL ​​non-OFDMA transmission to multiple users (where the UL / DL field in the U-SIG field is set to 0, and the PPDU Type and Compression Mode field is set to 2), the number of user fields is indicated by the Number Of Non-OFDMA Users subfield. The common fields of the EHT-SIG content channel are encoded together with the first user field of the same content channel. This common encoding block includes the CRC and the Tail. For non-OFDMA transmission to multiple users, the remaining user fields (if any) of each content channel are grouped into user encoding blocks using the same method as for OFDMA transmission.

[0182] The content of the user field is defined based on whether the user field is set for a user in the RU's non-MU-MIMO assignment or for a user in the RU's MU-MIMO assignment. For EHT SU transmission, the user field format for the non-MU-MIMO assignment is used.

[0183] Table 10 shows examples of user field formats for non-MU-MIMO allocation.

[0184]

[0185]

[0186] Table 11 provides examples of user field formats for MU-MIMO allocation.

[0187]

[0188] Unequal Modulation (UEQM)

[0189] Multiple spatial streams can be transmitted through multiple antennas after undergoing encoding, modulation, etc. Multiple spatial streams transmitted through the multiple antennas of a transmitter can be received through the multiple antennas of a receiver.

[0190] In transmission / reception via multiple antennas, two methods can be considered for the modulation of the spatial streams. One is to apply a single modulation scheme to all streams when modulating multiple data streams, and the other is to set a modulation scheme for each of the multiple data streams. The former modulation scheme can be referred to as equal modulation (EQM), and the latter modulation scheme as unequal modulation (UEQM).

[0191] EQM has the advantage of reducing the complexity of transmitters and receivers and using relatively few bits to inform the receiver of the modulation scheme used by the transmitter, as it applies the same modulation scheme to all streams. However, when multiple streams are transmitted, the modulation scheme cannot be adjusted to reflect the different environments of each channel. This means that when determining the modulation scheme for overall data transmission, the scheme and modulation order are determined by the worst-performing channel. Consequently, even for spatial streams transmitted through relatively good wireless channels, a low-order modulation scheme may be applied, which can ultimately lead to a waste of wireless resources.

[0192] Unlike EQM, UEQM results in somewhat higher complexity for both the transmitter and the receiver. Furthermore, the transmitter must use more bits to inform the receiver of the modulation scheme applied to each stream. When transmitting data through N spatial streams, if one of P modulation schemes is applied to each stream when using UEQM, the total number of possible cases is P N It becomes. P N This means that a bit value capable of indicating various cases must be used to indicate the modulation method. (When using an MCS table to indicate the modulation method, the index value is 0~P N It becomes -1.)

[0193] However, depending on the channel conditions of each spatial stream, there is an advantage in that transmission optimized for the wireless channel conditions is possible by applying a relatively high modulation order to streams transmitted over good channels and a low modulation order to streams transmitted over poor channels. This means that limited wireless resources can be utilized efficiently.

[0194] Table 12 shows the number of spatial streams (N) in a 20 MHz channel. SS )=2, Number of binary convolutional coding (BCC) encoders for the data field (N ES Examples of MCS parameters when UEQM is applied for )=1.

[0195]

[0196] Table 13 shows the number of spatial streams (N) in a 20 MHz channel. SS )=3, number of BCC encoders for data field(N ES Examples of MCS parameters when UEQM is applied for )=1.

[0197]

[0198] Table 14 shows the number of spatial streams (N) in a 20 MHz channel. SS )=4, number of BCC encoders for data field(N ES Examples of MCS parameters when UEQM is applied for )=1.

[0199]

[0200]

[0201] Table 15 shows the number of spatial streams (N) in a 40 MHz channel. SS Example of MCS parameters when UEQM is applied for )=2 and the number of BCC encoders (NES) for the data field=1.

[0202]

[0203] Table 16 shows the number of spatial streams (N) in a 40 MHz channel. SS Example of MCS parameters when UEQM is applied for )=3.

[0204]

[0205] Table 17 shows the number of spatial streams (N) in a 40 MHz channel. SS Example of MCS parameters when UEQM is applied for )=4.

[0206]

[0207]

[0208] Trigger frame

[0209] FIG. 12 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0210] A trigger frame may allocate resources for one or more TB PPDU transmissions and request TB PPDU transmissions. The trigger frame may also include other information required by an STA that transmits a TB PPDU in response. The trigger frame may include common info and user info list fields in the frame body.

[0211] The common information field may include information that is commonly applied to one or more TB PPDU transmissions requested by the trigger frame, for example, trigger type, UL length, whether there is a subsequent trigger frame (e.g., More TF), whether there is a CS (channel sensing) request, UL BW (bandwidth), etc.

[0212] The user information list contains zero or more user info fields. Figure 12 illustrates an exemplary EHT variant user info field format.

[0213] The AID12 subfield basically indicates that it is a user information field for the STA with the corresponding AID. Additionally, if the AID12 field has a specific predetermined value, it may be utilized for other purposes, such as assigning a Random Access (RA)-RU or being configured as a special user info field. A special user info field is a user information field that does not contain user-specific information but includes extended common information not provided in the common information field. For example, a special user info field can be identified by an AID12 value of 2007, and a special user info field flag subfield within the common information field can indicate whether the special user info field is included.

[0214] The RU allocation subfield can indicate the size and location of the RU / MRU. To this end, the RU allocation subfield may be interpreted together with the PS160 (primary / secondary 160MHz) subfield of the user information field, the UL BW subfield of the common information field, etc. For example, the mapping of B7-B1 of the RU allocation subfield can be defined together with the settings of B0 of the RU allocation subfield and the PS160 subfield.

[0215] FIG. 13 is a diagram showing the format of a common information field within a trigger frame to which the present disclosure can be applied.

[0216] Referring to FIG. 13, the EHT variant common information field may include information that is commonly applied to one or more TB PPDU transmissions requested by the trigger frame.

[0217] The EHT variant common information field includes a trigger type subfield that identifies the trigger frame variant.

[0218] Table 18 shows examples of trigger type subfield encodings.

[0219]

[0220] In addition, the EHT variant common information fields include the UL length subfield indicating the L-SIG length field of the solicited TB PPDU, the More TF subfield indicating whether a subsequent trigger frame (TF) is scheduled, the number of HE / EHT-LTF symbols subfield indicating the EHT-LTF symbols, the LDPC extra symbol segment subfield indicating the status of the LDPC (low-density parity check) symbol segment, the AP Tx power subfield indicating the combined transmit power of the AP at the transmit antenna connectors of all antennas used for triggering PPDU transmission, the pre-FEC (forward error correction) padding factor subfield, the PE (packet extension) disambiguity subfield, and the UL spatial reuse subfield. It may include the HE / EHT P160 subfield, the special user info field flag subfield, and the trigger dependent common info subfield.

[0221] The user information fields of the trigger frame include three variants: i) the Special User Info field (see Fig. 14), ii) the HE variant User Info field, and iii) the EHT variant User Info field (see Fig. 13).

[0222] The user information field addressed to the Non-AP STA corresponds to the HE variant or EHT variant. If B39 of the user information field is set to 0 and B54 of the common information field is set to 1 in the trigger frame, the user information field is the HE variant addressed to the non-AP EHT STA. Otherwise, it is the EHT variant. B39 of the HE variant user information field is reserved for the non-EHT HE STA. B39 is set to 0 for the HE variant user information field by the EHT AP and is the PS160 subfield for the EHT variant user information field.

[0223] Table 19 illustrates valid combinations of B54 and B55 of the common information fields, B39 of the user information field, and the solicited TB PPDU.

[0224]

[0225] Referring to Table 19, valid combinations are defined for B54 and B55 of the common information fields, B39 of the user information field, the existence of the special user information field in the trigger frame, variants of the user information field, and the corresponding TB PPDU types.

[0226] FIG. 14 illustrates a special user information field of a trigger frame to which the present disclosure can be applied.

[0227] Referring to FIG. 14, the special user information field does not carry user-specific information but carries extended common information not provided within the common information field. The special user information field is identified by the 2007 value of AID12 and is optionally present within the trigger frame generated by the EHT AP.

[0228] If a special user information field exists, it is located immediately after the common information field of the trigger frame and carries information about the U-SIG field of the solicited EHT TB PPDU.

[0229] The special user information field may be configured to include the AID12 subfield, the PHY Version Identifier subfield, the UL Bandwidth Extension subfield, the EHT Spatial Reuse 1 subfield, the EHT Spatial Reuse 2 subfield, the U-SIG Disregard And Validate subfield, reserved bits, and the Trigger Dependent User Info subfield.

[0230] The physical version identifier subfield indicates the PHY version of the solicited TB PPDU, not the HE TB PPPDU. The physical version identifier subfield is set to 0 for EHT. Values ​​from 1 to 7 are reserved.

[0231] The uplink bandwidth extension subfield indicates the bandwidth of the solicited TB PPDU together with the UL BW subfield of the common information field (i.e., bandwidth within the U-SIG field of the EHT TB PPDU).

[0232] Table 20 shows the encoding of the uplink bandwidth extension subfield.

[0233]

[0234] UEQM (unequal modulation) indication method

[0235] Next-generation Wi-Fi (beyond 11be) aims to support ultra-high reliability (UHR) when transmitting signals to STAs, and to achieve this, various technologies are being considered to support high throughput, low latency, and extended range. To this end, next-generation Wi-Fi / 11bn is considering the application of unequal modulation (UEQM), which transmits signals by applying different modulations to each spatial stream to account for signal-to-noise ratio (SNR) imbalance when transmitting via MIMO / beamforming using two or more spatial streams.

[0236] Accordingly, the present invention proposes a method for indicating modulation applied per spatial stream during MIMO / beamforming transmission when a STA transmits a TB PPDU using UEQM in uplink (UL) transmission.

[0237] When transmitting signals using MIMO / beamforming, the signal is transmitted using a beamforming matrix formed based on singular value decomposition (SVD). Therefore, when transmitting signals using multiple spatial streams, the MIMO gain or SNR becomes concentrated in some spatial streams, including the first spatial stream, resulting in an imbalance between spatial streams.

[0238] Channel information formed based on SVD can be expressed as shown in Equation 1 below.

[0239]

[0240] In Equation 1, H represents the channel matrix, U and V* are unitary matrices, and the singular values ​​of the diagonal matrix represent the power values ​​carried by each stream, with non-zero values ​​arranged in descending order. Therefore, when using multiple spatial streams in this way, a difference in SNR occurs between the spatial streams.

[0241] FIG. 15 illustrates the difference in SNR between multiple spatial streams in a wireless communication system to which the present disclosure may be applied.

[0242] Figure 15 illustrates the difference in SNR between the first space stream and the remaining space streams when using four space streams at 80 MHz.

[0243] In Fig. 15, it can be seen that an SNR gap occurs between spatial streams when performing MIMO / beamforming transmission using multiple spatial streams. Since spatial streams have different SNRs, signal transmission efficiency may decrease due to the SNR gap when the same MCS is applied to multiple spatial streams during MIMO / beamforming transmission. Therefore, by applying modulation suitable for the SNR individually to each spatial stream, i.e., applying UEQM, to transmit signals while considering the SNR gap, signal transmission efficiency can be improved and throughput can also be improved.

[0244] In the description of the present disclosure, UEQM may mean applying different modulations for the same coderate per spatial stream.

[0245] In addition, the UEQM according to the present disclosure may be composed of a combination of QPSK (Quadrature Phase Shift Keying), 16 QAM (Quadrature Amplitude Modulation), 64 QAM, 256 QAM, 1024 QAM, 4096 QAM, etc., and may support code rates such as 1 / 2, 3 / 4, 5 / 6.

[0246] UEQM can mean applying different modulations to different spatial streams using the same code rate. For example, if two spatial streams are allocated to an STA, a code rate of 1 / 2 is applied to form coded bits, and these formed coded bits can be modulated using a modulation order set for each spatial stream (e.g., spatial stream 1 = 16 QAM, spatial stream 2 = QPSK). Combinations of UEQM can be configured in various ways depending on the number of spatial streams, the code rate, and the modulation.

[0247] A UEQM combination configured as in the example above can be configured in the following way.

[0248] - Different modulation orders can be applied per spatial stream for the same code rate.

[0249] - Alternatively, the modulation order assigned per spatial stream is configured in descending order according to the specific order of the spatial streams (e.g., ascending or descending order of the spatial stream indices).

[0250] For example, the number of spatial streams (N SS When ) = 4, the modulation order of space stream 1 is equal to or greater than the modulation order of space stream 2, and the modulation order of space stream 2 can be set to be equal to or greater than space stream 3. That is, the modulation order of the last space stream can be set to a smaller order than the other space streams.

[0251] Modulation order of spatial stream 1 ≥ Modulation order of spatial stream 2 ≥ Modulation order of spatial stream 3 ≥ Modulation order of spatial stream 4

[0252] The above example is just one example and can be applied in the same way to cases where the number of space streams is 8 or less.

[0253] Additionally, the UEQM according to the present disclosure may be applied during single-user (SU), OFDMA, and multi-user MIMO (MU-MIMO) transmissions. Additionally, the UEQM according to the present disclosure may be applied during transmissions using 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, 996-tone RU, 2x996-tone RU, 4x996-tone RU, and multiple RUs (MRU) as defined in 11be.

[0254] To transmit and receive signals using UEQM in 802.11bn or next-generation Wi-Fi (i.e., beyond the 802.11be standard), support for UEQM can be determined through capability exchange between the AP and the STA. A STA's support for UEQM can be defined through its capabilities. For example, support for UEQM can be defined as follows through the physical layer (PHY) capabilities of UHR or next-generation Wi-Fi.

[0255] FIG. 16 illustrates a method for indicating UEQM capability according to one embodiment of the present disclosure.

[0256] As shown in FIG. 16, the PHY capabilities Information field of the UHR or next-generation Wi-Fi can be used to indicate the UEQM capability (or whether UEQM is supported) of the STA.

[0257] The PHY capabilities Information field of the UHR or next-generation Wi-Fi according to the present disclosure may be configured by extending the EHT PHY capabilities Information field format, and FIG. 16 illustrates only the parts that are changed compared to the EHT PHY capabilities Information field format for convenience of explanation.

[0258] In the EHT PHY capabilities information field, B69 (bit 69) through B71 (bit 71) are reserved bits, but in the PHY capabilities information field of UHR or next-generation Wi-Fi according to the present disclosure, some of the reserved bits may be used to indicate UEQM capabilities.

[0259] For example, as shown in FIG. 16, B69 (bit 69) can be defined as a UEQM support field for indicating UEQM capability (or whether UEQM is supported).

[0260] The UEQM (UnEqualModulation) support field can be set to 1 to indicate UEQM support, or to 0 to indicate that UEQM is not applied. These values ​​are examples, and the opposite value may also be set.

[0261] However, FIG. 16 is merely an example and the present disclosure is not limited thereto. That is, UEQM support may be defined / indicated through a field / subfield newly defined (e.g., using a spare bit other than B69 or modifying an existing field) in the PHY capabilities Information field of the UHR or next-generation Wi-Fi according to the present disclosure.

[0262] Additionally, the name of the UEQM (UnEqualModulation) support field is one example and can be defined with a different field name.

[0263] For example, the aforementioned UEQM support field can be included and transmitted within an association request / response frame or a probe request / response frame between the AP and the STA, and through the exchange of the frames, they can mutually inform each other whether UEQM is supported.

[0264] As described above, when UEQM support is enabled by setting the UEQM support field to 1 through linkage with AP or capability negotiation, when transmitting a signal using TB PPDU during UL MIMO / beamforming transmission, the signaling for the modulation applied to each spatial stream, i.e., the signaling for UEQM, can be defined / configured as follows.

[0265] A triggering frame that triggers or requests a TB PPDU may include i) a frame containing a TRS control (sub)field or ii) a trigger frame. Each of these is described below.

[0266] Example 1: Instruction using a triggered response scheduling (TRS) control field (i.e., a field included in the A-control field)

[0267] Trigger-based (TB) PPDUs for 802.11bn or next-generation Wi-Fi can be requested through the TRS control (sub)field included in the DL PPDU. Here, UEQM can be applied to the TB PPDU to instruct the STA through the TRS control field whether a signal is transmitted.

[0268] That is, through a TRS control field included in a DL PPDU (e.g., a triggering frame) and transmitted, it may indicate whether the requested (solicit) TB PPDU is transmitted with UEQM applied, wherein the TRS control field may be configured to include a subfield (e.g., a UEQM subfield) for indicating whether UEQM is applied.

[0269] - The UEQM subfield can be composed of 1 bit, and can be set to 1 to indicate that unequal modulation (UEQM) is applied and the signal is modulated, or set to 0 to indicate that equal modulation (EQM) is applied and the signal is modulated. Alternatively, it can be set to the opposite value.

[0270] Here, the UEQM subfield is an example and the present disclosure is not limited thereto and may be defined by a field of a different name.

[0271] FIG. 17 illustrates a TRS control field according to one embodiment of the present disclosure.

[0272] Referring to FIG. 17, the TRS control field (or control information subfield within the TRS control subfield) may be configured to include a UL data symbols subfield, a RU allocation subfield, an AP Tx power subfield, an uplink target received power subfield, an uplink MCS (UL MCS) subfield, and a UEQM subfield.

[0273] The UL data symbols subfield indicates the number of OFDM symbols in the data field of the TB PPDU response and can be set to a value 1 minus the number of OFDM symbols.

[0274] The RU allocation subfield may indicate the RU allocated to send the TB PPDU response.

[0275] The AP Tx power subfield may represent the combined transmission power of the AP at the transmission antenna connectors of all antennas used to transmit the triggering PPDU (e.g., in dBm / 20MHz units).

[0276] The UL target receive power subfield may represent the expected received signal power measured at the AP's antenna connector and averaged across the antenna for a portion of the TB PPDU transmitted from the assigned RU.

[0277] The UL MCS subfield represents the MCS and can be set as the MCS index to be used by the receiving STA for the TB PPDU.

[0278] The UEQM subfield can indicate whether UEQM or EQM applies to the TB PPDU.

[0279] Through the UEQM subfield of the TRS control field configured as above, the STA can determine whether to use UEQM when transmitting the requested (solicit) TB PPDU.

[0280] Example 2: Signaling to the UEQM can be indicated through a trigger frame.

[0281] When signaling for UEQM (i.e., transmission of UL PPDU with UEQM applied) is indicated through a trigger frame, an indication of whether UEQM is applied may be included in the following fields and transmitted.

[0282] 1) When transmitted included in common information fields

[0283] When an AP solicits a TB PPDU from an STA(s), it may request the addressed STA(s) via a trigger frame to apply UEQM to the TB PPDU in common and transmit it. Accordingly, information regarding UEQM (i.e., information on whether UEQM is applied) may be included in the common information field of the trigger frame that the AP transmits to the STA.

[0284] Information about UEQM (i.e., information about whether UEQM is applied) can be defined / set through the UEQM subfield, and the UEQM subfield can be composed of 1 bit.

[0285] For example, when a UHR variant trigger frame is formed / configured based on an EHT variant trigger frame, a UEQM subfield can be defined using one of the reserved bits (i.e., B22 (bit 22), B26 (bit 26), B53 (bit 53), B63 (bit 63)) among the bits of the common information field of the EHT variant trigger frame (see FIG. 13).

[0286] The above UEQM subfield can be set to 1 to indicate that UEQM is used for UL TB PPDPU transmission, or set to 0 to indicate that UEQM is not used for UL TB PPDPU transmission (i.e., EQM (Equal modulation) is used). Or it may be set to the opposite.

[0287] FIG. 18 illustrates a portion of the common information field of a trigger frame according to one embodiment of the present disclosure.

[0288] For example, as shown in FIG. 18, the UEQM subfield can be defined using B26 (bit 26) within the common information field. In addition, the common information field may include an LDPC extra symbol segment subfield, an AP Tx power subfield indicating the combined transmission power of the AP at the transmission antenna connector of all antennas used for triggering PPDU transmission, a pre-FEC (forward error correction) padding factor subfield, a PE (packet extension) disambiguity subfield, etc.

[0289] However, the common information field of a trigger frame including the UEQM subfield exemplified in FIG. 18 is merely one example and is not limited thereto. That is, for convenience of explanation, FIG. 18 describes subfields other than the UEQM subfield by assuming they are subfields of the EHT variant common information field (see FIG. 13), but the common information field of a trigger frame may be composed of subfields different from these. For example, the common information field may be composed by including other subfields not exemplified in FIG. 18, or the common information field may be composed by excluding or modifying one or more of the subfields exemplified in FIG. 18.

[0290] In addition, Figure 18 illustrates an example in which the UEQM subfield is defined using B26 (bit 26), but as described above, the UEQM subfield may also be defined using other bits (e.g., B26 (bit 26), B53 (bit 53), B63 (bit 63), etc.).

[0291] 2) When transmitted included in a special user field

[0292] The trigger frame transmitted to solicit a TB PPDU for UHR or next-generation Wi-Fi is configured to include a special user info field.

[0293] The Physical Version Identifier (PHY Version Identifier) ​​subfield of the Special User Information field can be set to 1 to indicate UHR or next-generation Wi-Fi (i.e., beyond 802.11be standard).

[0294] Here, if the physical version identifier subfield of the special user information field is set to 1, the special user information field may be configured to include a subfield containing UEQM information (i.e., information on whether UEQM is applied).

[0295] Information regarding UEQM (i.e., information on whether UEQM is applied) can be defined / configured through the UEQM subfield, and the UEQM subfield can consist of 1 bit. For example, the UEQM subfield can be set to 1 to indicate that UEQM (unequal modulation) is applied, and set to 0 to indicate that it is not used (i.e., EQM (equal modulation) is used). Alternatively, the opposite is possible.

[0296] FIG. 19 illustrates a portion of a special user information field of a trigger frame according to one embodiment of the present disclosure.

[0297] For example, the UEQM subfield can be defined using one of the bits B37 (bit 37) to B39 (bit 39) of the special user information field. As one embodiment, it can be defined using B37 (bit 37) as shown in FIG. 19.

[0298] However, the part of the special user information field of the trigger frame including the UEQM subfield exemplified in FIG. 19 is merely one example and the present disclosure is not limited thereto. That is, for convenience of explanation, FIG. 19 describes subfields other than the UEQM subfield by assuming they are subfields of the EHT variant special user information field (see FIG. 14), but the special user information field of the trigger frame may be composed of subfields different from these. For example, the special user information field may be composed by including other subfields not exemplified in FIG. 19, or the special user information field may be composed by excluding or modifying one or more of the subfields exemplified in FIG. 19.

[0299] 3) Since UEQM can be applied according to the capabilities of the STA, for flexible UL transmission, UEQM or EQM can be applied individually to each STA transmitting TB PPDU to transmit TB PPDU to the AP. In order to solicit the transmission of TB PPDU by applying STA-specific UEQM in this way, information about the UEQM can be transmitted through the user information field of the trigger frame of UHR or next-generation Wi-Fi (i.e., beyond the 802.11be standard).

[0300] Information regarding UEQM (i.e., information on whether UEQM is applied) can be transmitted by including it in the user information field and can be defined / configured as a UEQM subfield.

[0301] The UEQM subfield can consist of 1 bit. For example, the UEQM subfield can be set to 1 to indicate that UEQM (unequal modulation) is applied, or set to 0 to indicate that it is not used (i.e., EQM (equal modulation) is used). Or, the opposite is also possible.

[0302] FIG. 20 illustrates a portion of the user information field of a trigger frame according to one embodiment of the present disclosure.

[0303] For example, as shown in FIG. 20, the UEQM subfield can be defined using B25 (bit 25) within the user information field.

[0304] However, the user information field of a trigger frame including the UEQM subfield exemplified in FIG. 20 is merely one example and the present disclosure is not limited thereto. That is, for convenience of explanation, FIG. 20 describes subfields other than the UEQM subfield by assuming they are subfields of the EHT variant user information field (see FIG. 12), but the user information field of a trigger frame may be composed of subfields different from these. For example, the user information field may be composed by including other subfields not exemplified in FIG. 20, or the user information field may be composed by excluding or modifying one or more of the subfields exemplified in FIG. 20.

[0305] For example, a specified (addressed) STA that receives a trigger frame with the UEQM subfield within the user information field set to 1 can recognize that UEQM is being used. Here, the STA [represents] the number of space streams (N) allocated through SS (space stream) allocation. SS Identify information about ).

[0306] And, STA is the number of spatial streams identified above (N SS By using ) and UL MCS information, it is possible to identify the modulation applied per spatial stream during MIMO / beamforming transmission.

[0307] UL MCS fields may consist of different content or information depending on whether UEQM is applied. In other words, STA may interpret UL MCS fields differently depending on whether UEQM is applied.

[0308] Also, even when UEQM = 1, the number of allocated space streams (N SS It can be composed of different content or information depending on ). In other words, STA can interpret UL MCS fields differently depending on whether UEQM is applied.

[0309] For example, if UEQM = 0, UL MCS = 0 is set to represent MCS0, but if UEQM = 1, N SS Depending on the, it can be composed of different modulation information as follows.

[0310] For example, N SS When = 2, UL MCS 0 may indicate that 16QAM and QPSK are applied in the order of each spatial stream. As another example, N SS When = 4, UL MCS 0 may indicate that 64QAM, 16QAM, 16QAM, and QPSK are applied in the order of each spatial stream.

[0311] The above combination of modulation orders is merely an example for convenience of explanation and is not limited thereto. In other words, various combinations of modulation orders according to UL MCS values ​​may be considered.

[0312] The above description explains the case where the UEQM subfield is defined using B25 (bit 25) within the user information field, but alternatively, the UEQM subfield may be defined within the trigger-dependent user info subfield. In this case, the method of configuring the UEQM subfield described above, or the method of interpreting the UL MCS based thereon, etc., can be applied in the same way as the proposed method described above, and a detailed explanation thereof is omitted.

[0313] Meanwhile, an STA that receives information regarding unequal modulation (UEQM) defined according to the method of Example 1 or 2 described above applies it and transmits a TB PPDU to an AP. Here, in order to indicate that the TB PPDU transmitted by the STA is transmitted using UEQM, the TB PPDU transmitted by the STA includes information regarding UEQM.

[0314] Indicators on whether a signal / PPDU is transmitted using UEQM can be indicated through the U-SIG field of the TB PPDU.

[0315] That is, the U-SIG field of the TB PPDU can be configured to include the UEQM subfield. The U-SIG field can be divided into version-dependent fields / bits and version-independent fields / bits, and the UEQM subfield can be defined as a version-dependent field / bit.

[0316] In 802.11be, B20 (bit 20) through B24 (bit 24) of U-SIG1 are defined as disregard bits, and B25 (bit 25) of U-SIG1, and B2 (bit 2) and B8 (bit 8) of U-SIG2 are defined as validate bits. For example, the UEQM subfield can be defined using one of the disregard or validate bits defined in U-SIG1 in 802.11be. In other words, the UEQM subfield can be defined using one of the bits from B20-B24, B25 of U-SIG1, and B2, B8 of U-SIG2.

[0317] An AP receiving a TB PPDU can determine whether the TB PPDU is transmitted with EQM applied or with UEQM applied through the setting (i.e., setting value) of the UEQM subfield included in the U-SIG of the TB PPDU transmitted from the STA. Here, for example, the UEQM subfield can be set to 1 to indicate the application of UEQM, or set to 0 to indicate that the signal is transmitted with EQM applied, and vice versa.

[0318] FIG. 21 illustrates the operation of an STA device for a PPDU transmission and reception method according to one embodiment of the present disclosure.

[0319] FIG. 21 illustrates the operation of an STA device based on the previously proposed methods. The example in FIG. 21 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 21 may be omitted depending on the situation and / or configuration.

[0320] Referring to FIG. 21, the STA device receives a triggering frame from the AP device (S2101).

[0321] Here, the triggering frame may include instruction information indicating whether EQM or UEQM is applied for the transmission of the PPDU.

[0322] For example, the triggering frame may be a trigger frame and may be a frame containing a TRS control field.

[0323] Here, the above instruction information may be commonly applied to one or more STAs designated by the triggering frame.

[0324] In this case, the triggering frame is a trigger frame, and the instruction information may be included within the common info field of the trigger frame. For example, the instruction information may be defined as one of bits 22, 26, 53, or 63 within the common info field. Alternatively, the triggering frame is a trigger frame, and

[0325] Alternatively, the instruction information may be included in the special user info field of the trigger frame. For example, the instruction information may be defined as one of bits 37, 38, or 39 in the special user info field.

[0326] In addition, the above instruction information may be applied individually to one or more STAs designated by the triggering frame.

[0327] In this case, the triggering frame is a trigger frame, and the instruction information may be included in the special user info field of the trigger frame. For example, the instruction information may be defined as bit 25 in the special user info field or in the trigger dependent user info field.

[0328] Here, the uplink modulation and coding technique (UL MCS) subfield within the special user info field may be configured differently based on whether EQM or UEQM is applied for the transmission of the PPDU according to the instruction information. That is, even if the same value is indicated in the UL MCS subfield, the content / information indicated by the value of the UL MCS subfield may be configured differently depending on whether UEQM is applied.

[0329] In addition, when UEQM is applied for the transmission of the PPDU, the uplink modulation and coding technique (UL MCS) subfield within the special user info field may be configured differently based on the number of space streams allocated for the transmission of the PPDU. That is, even if the same value is indicated in the UL MCS subfield, the content / information indicated by the value of the UL MCS subfield may be configured differently depending on the number of space streams.

[0330] Additionally, the triggering frame includes a triggered response scheduling (TRS) control field, and the instruction information may be included within the TRS control field.

[0331] Meanwhile, although not illustrated in FIG. 21, the STA may transmit capability information regarding whether the UEQM is supported to the AP. Here, for example, the capability information may be transmitted through at least one of a physical layer capability information field, an association request / response frame, or a probe request / response frame.

[0332] The STA device transmits a PPDU (physical protocol data unit) (i.e., TB PPDU) to the AP device based on the triggering frame (S2102).

[0333] Here, the U-SIG field (or UHR-SIG field) in the PPDU may include a 1-bit indication indicating whether equal modulation (EQM) or uneven modulation (UEQM) is applied for the transmission of the PPDU.

[0334] For example, the UEQM may be applied to the resource unit corresponding to the user field based on the 1-bit instruction value being set to 1, and the EQM may be applied to the resource unit corresponding to the user field based on the 1-bit instruction value being set to 0.

[0335] In step S2102, the PPDU may be configured to include a legacy part, a SIG part (e.g., U-SIG, UHR-SIG, etc.), an STF part (e.g., UHR-STF), an LTF part (e.g., UHR-LTF), and a data part.

[0336] All or part of every part (i.e., field) may be divided into multiple sub-parts / sub-fields. Each field (and its sub-fields) may be transmitted in units of 4us * N (where N is an integer). Additionally, a guard interval (GI) may be included. A common subcarrier frequency spacing value (delta_f = 312.5 kHz / N or 312.5 kHz * N, where N is an integer) may be applied to the entire field, or a first delta_f may be applied to the first part (e.g., the entire legacy part, all / part of the SIG part), and a second delta_f (e.g., a value smaller than the first delta_f) may be applied to all / part of the remaining part.

[0337] Some of the aforementioned fields may be omitted, and the order of the fields may be changed in various ways. For example, the subfields of the signal-part may be placed before the STF-part, and the remaining subfields of the SIG-part may be placed after the STF-part.

[0338] The aforementioned legacy portion may include at least one of the conventional L-STF (Non-HT Short Training Field), L-LTF (Non-HT Long Training Field), and L-SIG (Non-HT Signal Field).

[0339] The aforementioned SIG portion (including, for example, the U-SIG field, UHR-SIG field, etc.) may include various control information for the transmitted PPDU. For example, it may include an STF portion, an LTF portion, and control information for decoding the data.

[0340] The aforementioned STF-part (e.g., U-STF field) may contain an STF sequence.

[0341] The aforementioned LTF-part (e.g., U-LTF field) may include a training field (i.e., LTF sequence) for channel estimation.

[0342] It includes the aforementioned data-part user data and may include packets for the upper layer (e.g., MPDU).

[0343] The method described in the example of FIG. 21 can be performed by the first device (100) of FIG. 1. For example, one or more processors (102) of the first device (100) of FIG. 1 may be configured to generate a PPDU and transmit the PPDU through transceiver(s) (106). Furthermore, one or more memories (104) of the first device (100) may store instructions for performing the method described in the example of FIG. 21 or the examples described above when executed by one or more processors (102).

[0344] FIG. 22 illustrates the operation of an AP device for a PPDU transmission and reception method according to one embodiment of the present disclosure.

[0345] FIG. 22 illustrates the operation of an AP device based on the previously proposed methods. The example in FIG. 22 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 22 may be omitted depending on the situation and / or configuration.

[0346] Referring to FIG. 22, the AP device transmits a triggering frame to the STA device (S2201).

[0347] Here, the triggering frame may include instruction information indicating whether EQM or UEQM is applied for the transmission of the PPDU.

[0348] For example, the triggering frame may be a trigger frame and may be a frame containing a TRS control field.

[0349] Here, the above instruction information may be commonly applied to one or more STAs designated by the triggering frame.

[0350] In this case, the triggering frame is a trigger frame, and the instruction information may be included within the common info field of the trigger frame. For example, the instruction information may be defined as one of bits 22, 26, 53, or 63 within the common info field. Alternatively, the triggering frame is a trigger frame, and

[0351] Alternatively, the instruction information may be included in the special user info field of the trigger frame. For example, the instruction information may be defined as one of bits 37, 38, or 39 in the special user info field.

[0352] In addition, the above instruction information may be applied individually to one or more STAs designated by the triggering frame.

[0353] In this case, the triggering frame is a trigger frame, and the instruction information may be included in the special user info field of the trigger frame. For example, the instruction information may be defined as bit 25 in the special user info field or in the trigger dependent user info field.

[0354] Here, the uplink modulation and coding technique (UL MCS) subfield within the special user info field may be configured differently based on whether EQM or UEQM is applied for the transmission of the PPDU according to the instruction information. That is, even if the same value is indicated in the UL MCS subfield, the content / information indicated by the value of the UL MCS subfield may be configured differently depending on whether UEQM is applied.

[0355] In addition, when UEQM is applied for the transmission of the PPDU, the uplink modulation and coding technique (UL MCS) subfield within the special user info field may be configured differently based on the number of space streams allocated for the transmission of the PPDU. That is, even if the same value is indicated in the UL MCS subfield, the content / information indicated by the value of the UL MCS subfield may be configured differently depending on the number of space streams.

[0356] Additionally, the triggering frame includes a triggered response scheduling (TRS) control field, and the instruction information may be included within the TRS control field.

[0357] Meanwhile, although not illustrated in FIG. 21, the STA may transmit capability information regarding whether the UEQM is supported to the AP. Here, for example, the capability information may be transmitted through at least one of a physical layer capability information field, an association request / response frame, or a probe request / response frame.

[0358] The AP device receives a PPDU (physical protocol data unit) (i.e., TB PPDU) from the STA device based on a triggering frame (S2202).

[0359] Here, the U-SIG field (or UHR-SIG field) in the PPDU may include a 1-bit indication indicating whether equal modulation (EQM) or uneven modulation (UEQM) is applied for the transmission of the PPDU.

[0360] For example, the UEQM may be applied to the resource unit corresponding to the user field based on the 1-bit instruction value being set to 1, and the EQM may be applied to the resource unit corresponding to the user field based on the 1-bit instruction value being set to 0.

[0361] In step S2202, the PPDU may be configured to include a legacy part, a SIG part (e.g., U-SIG, UHR-SIG, etc.), an STF part (e.g., UHR-STF), an LTF part (e.g., UHR-LTF), and a data part.

[0362] All or part of every part (i.e., field) may be divided into multiple sub-parts / sub-fields. Each field (and its sub-fields) may be transmitted in units of 4us * N (where N is an integer). Additionally, a guard interval (GI) may be included. A common subcarrier frequency spacing value (delta_f = 312.5 kHz / N or 312.5 kHz * N, where N is an integer) may be applied to the entire field, or a first delta_f may be applied to the first part (e.g., the entire legacy part, all / part of the SIG part), and a second delta_f (e.g., a value smaller than the first delta_f) may be applied to all / part of the remaining part.

[0363] Some of the aforementioned fields may be omitted, and the order of the fields may be changed in various ways. For example, the subfields of the signal-part may be placed before the STF-part, and the remaining subfields of the SIG-part may be placed after the STF-part.

[0364] The aforementioned legacy portion may include at least one of the conventional L-STF (Non-HT Short Training Field), L-LTF (Non-HT Long Training Field), and L-SIG (Non-HT Signal Field).

[0365] The aforementioned SIG portion (including, for example, the U-SIG field, UHR-SIG field, etc.) may include various control information for the transmitted PPDU. For example, it may include an STF portion, an LTF portion, and control information for decoding the data.

[0366] The aforementioned STF-part (e.g., U-STF field) may contain an STF sequence.

[0367] The aforementioned LTF-part (e.g., U-LTF field) may include a training field (i.e., LTF sequence) for channel estimation.

[0368] It includes the aforementioned data-part user data and may include packets for the upper layer (e.g., MPDU).

[0369] The method described in the example of FIG. 22 can be performed by the second device (200) of FIG. 1. For example, one or more processors (202) of the second device (200) of FIG. 1 may be configured to receive a PPDU through transceiver(s) (106) and process the PPDU. Furthermore, one or more memories (204) of the second device (200) may store instructions for performing the method described in the example of FIG. 22 or the examples described above when executed by one or more processors (202).

[0370] In existing wireless LAN systems, when signals are transmitted and received by applying the same MCS to spatial streams during MIMO / beamforming transmission, performance degradation occurs due to power imbalance for each spatial stream. However, in contrast, according to the examples of the present disclosure, efficient transmission is possible by applying UEQM, which applies different modulation orders to each spatial stream during MIMO / beamforming transmission, thereby improving data transmission throughput. Furthermore, reception ambiguity of the receiving device can be reduced by indicating whether UEQM / EQM is used. Accordingly, the effect of increasing wireless communication efficiency can be achieved.

[0371] The embodiments described above are combinations of the components and features of the present disclosure in a specific form. Each component or feature should be considered optional unless otherwise explicitly stated. Each component or feature may be implemented in a form not combined with other components or features. Additionally, it is possible to construct embodiments of the present disclosure by combining some components and / or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components or features of another embodiment. It is obvious that embodiments may be constructed by combining claims that are not explicitly related in the claims, or that they may be included as new claims by amendment after filing.

[0372] It is obvious to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential features of the present disclosure. Accordingly, the detailed description set forth above should not be interpreted restrictively in all respects and should be considered exemplary. The scope of the present disclosure shall be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0373] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that enable operations according to the methods of various embodiments to be executed on a device or computer, and a non-transitory computer-readable medium on which such software or instructions, etc. are stored and executable on a device or computer. Instructions that may be used to program a processing system to perform the features described in the present disclosure may be stored on or within a storage medium or a computer-readable storage medium, and the features described in the present disclosure may be implemented using a computer program product comprising such a storage medium. The storage medium may include, but is not limited to, high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, and may include non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory may optionally include one or more storage devices located remotely from the processor(s). Memory or alternatively, non-volatile memory device(s) within memory comprises a non-transient computer-readable storage medium. The features described in this disclosure may be stored in any one of the machine-readable media and integrated into software and / or firmware that can control the hardware of a processing system and allow the processing system to interact with other mechanisms utilizing results according to the embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers. Industrial applicability

[0374] Although the method proposed in this disclosure has been described with an example applied to an IEEE 802.11-based system, it can be applied to various wireless LANs or wireless communication systems in addition to IEEE 802.11-based systems.

Claims

Claim 1 A method comprising: receiving a triggering frame from an access point (AP) by a station (STA); and transmitting a physical protocol data unit (PPDU) to the AP by the STA based on the triggering frame, wherein the triggering frame includes instruction information indicating whether equal modulation (EQM) or unequal modulation (UEQM) is applied for the transmission of the PPDU. Claim 2 A method according to claim 1, wherein the instruction information is commonly applied to one or more STAs designated by the triggering frame. Claim 3 A method according to paragraph 2, wherein the triggering frame is a trigger frame, and the instruction information is included in the common info field of the trigger frame. Claim 4 A method according to paragraph 3, wherein the instruction information is defined by one of bits 22, 26, 53, and 63 within the common info field. Claim 5 A method according to paragraph 2, wherein the triggering frame is a trigger frame, and the instruction information is included within the special user info field of the trigger frame. Claim 6 In paragraph 5, the method wherein the instruction information is defined by one of bits 37, 38, and 39 within the special user info field. Claim 7 A method according to claim 1, wherein the instruction information is individually applied to one or more STAs designated by the triggering frame. Claim 8 A method according to claim 7, wherein the triggering frame is a trigger frame, and the instruction information is included within the special user info field of the trigger frame. Claim 9 In claim 8, the method wherein the instruction information is defined as bit 25 in the special user info field or defined in the trigger dependent user info field. Claim 10 A method according to claim 8, wherein the uplink modulation and coding scheme (UL MCS) subfield within the special user info field is configured differently depending on whether EQM or UEQM is applied for the transmission of the PPDU by the instruction information. Claim 11 A method according to claim 8, wherein, when UEQM is applied for the transmission of the PPDU, the uplink modulation and coding scheme (UL MCS) subfield within the special user info field is configured differently based on the number of space streams allocated for the transmission of the PPDU. Claim 12 A method according to claim 1, wherein the triggering frame includes a triggered response scheduling (TRS) control field, and the instruction information is included within the TRS control field. Claim 13 A method according to claim 1, further comprising the step of transmitting capability information regarding whether the UEQM is supported to the AP by the STA. Claim 14 A method according to claim 13, wherein the capability information is transmitted through at least one of a physical layer capability information field, an association request / response frame, or a probe request / response frame. Claim 15 A station (STA) device comprises: one or more transceivers; and one or more processors connected to the one or more transceivers, wherein the one or more processors receive a triggering frame from an access point (AP), and are configured to transmit a physical protocol data unit (PPDU) to the AP based on the triggering frame, and the triggering frame includes instruction information indicating whether equal modulation (EQM) or unequal modulation (UEQM) is applied for the transmission of the PPDU. Claim 16 A method comprising: transmitting a triggering frame to a station (STA) by an access point (AP); and receiving a physical protocol data unit (PPDU) from the STA by the AP based on the triggering frame, wherein the triggering frame includes instruction information indicating whether equal modulation (EQM) or unequal modulation (UEQM) is applied for the transmission of the PPDU. Claim 17 An access point (AP) device comprising: one or more transceivers; and one or more processors connected to the one or more transceivers, wherein the one or more processors are configured to transmit a triggering frame to a station (STA) and receive a physical protocol data unit (PPDU) from the STA based on the triggering frame, and the triggering frame comprises instruction information indicating whether equal modulation (EQM) or unequal modulation (UEQM) is applied for the transmission of the PPDU. Claim 18 A processing device configured to control a station (STA) in a wireless LAN system, wherein the processing device comprises: one or more processors; and one or more computer memories operably connected to the one or more processors and storing instructions for performing a method according to any one of claims 1 to 12 based on execution by the one or more processors. Claim 19 One or more non-transitory computer-readable media storing one or more instructions, wherein the one or more instructions are executed by one or more processors to control a device in a wireless LAN system to perform a method according to any one of claims 1 through 12.

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