PPDU transmission and reception method and device for coordinated transmission in wireless LAN system

Abstract

Disclosed are a PPDU transmission and reception method and device for coordinated transmission in a wireless LAN system. The method performed by a first AP according to an embodiment of the present disclosure comprises the steps of: generating a first PPDU for coordinated transmission; and transmitting the first PPDU to one or more first STAs associated with the first AP.

Description

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

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

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

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

[0004] The technical problem of the present disclosure is to provide a method and apparatus for transmitting and receiving PPDUs for cooperative transmission (or concurrent transmission) (e.g., coordinated spatial reused (Co-SR) transmission or coordinated beamforming (Co-BF) transmission).

[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.

[0006] A method performed by a first access point (AP) in a wireless LAN system according to one aspect of the present disclosure may include: generating a first physical protocol data unit (PPDU) for cooperative transmission; and transmitting the first PPDU to one or more first stations (STAs) associated with the first AP. The first PPDU may include a common preamble with a second PPDU transmitted from a second AP for cooperative transmission to one or more second STAs, and the common preamble may include information regarding the number of the one or more first STAs.

[0007] A method performed by a first station (STA) in a wireless LAN system according to a further aspect of the present disclosure may include: receiving a first physical protocol data unit (PPDU) for cooperative transmission from a first access point (AP); and processing the first PPDU. The first PPDU may include a common preamble with a second PPDU transmitted from a second AP to one or more second STAs for cooperative transmission, and the common preamble may include a field for the number of the one or more first STAs.

[0008] According to the present disclosure, as multiple APs perform cooperative transmission (or concurrent transmission (e.g., Co-SR transmission or Co-BF transmission)), throughput can be improved and latency reduced, thereby increasing wireless communication efficiency.

[0009] In addition, according to the present disclosure, signaling overhead caused by unnecessary fields in the preamble of the PPDU for cooperative transmission can be reduced, and decoding performance can be improved.

[0010] 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.

[0011] 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.

[0012] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0013] FIG. 2 is a drawing showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0014] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0015] FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied.

[0016] FIG. 5 is a diagram illustrating a CSMA / CA-based frame transmission operation to which the present disclosure may be applied.

[0017] 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.

[0018] FIG. 7 is a drawing illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure may be applied.

[0019] Figure 8 shows an exemplary structure of the EHT-SIG content channel.

[0020] FIG. 9 illustrates a non-OFDMA common field of a UHR-SIG field according to one embodiment of the present disclosure.

[0021] FIG. 10 illustrates a MU-MIMO user field of a UHR-SIG field according to one embodiment of the present disclosure.

[0022] FIG. 11 illustrates a non-OFDMA common field of a UHR-SIG field according to one embodiment of the present disclosure.

[0023] FIG. 12 illustrates a MU-MIMO user field of a UHR-SIG field according to one embodiment of the present disclosure.

[0024] FIG. 13 illustrates a non-OFDMA common field of a UHR-SIG field according to one embodiment of the present disclosure.

[0025] FIG. 14 illustrates a MU-MIMO user field of a UHR-SIG field according to one embodiment of the present disclosure.

[0026] FIG. 15 is a drawing illustrating a PPDU format according to one embodiment of the present disclosure.

[0027] FIG. 16 illustrates the operation of an AP for a PPDU transmission and reception method for cooperative transmission according to one embodiment of the present disclosure.

[0028] FIG. 17 illustrates an STA operation for a PPDU transmission and reception method for cooperative transmission according to one embodiment of the present disclosure.

[0029] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below, together with the accompanying drawings, is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure may be practiced. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the art will know that the present disclosure may be practiced without such specific details.

[0030] In some cases, to avoid obscuring the concept of the present disclosure, known structures and devices may be omitted or illustrated in the form of a block diagram focusing on the core functions of each structure and device.

[0031] In the present disclosure, when a component is described as being “connected,” “combined,” or “joined” with another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, in the present disclosure, the terms “comprising” or “having” specify the presence of the mentioned features, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, actions, elements, components, and / or groups thereof.

[0032] In the present disclosure, terms such as "first," "second," etc. are used solely for the purpose of distinguishing one component from another and are not used to limit the components, nor do they limit the order or importance of the components unless specifically stated otherwise. Accordingly, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and likewise, a second component in one embodiment may be referred to as a first component in another embodiment.

[0033] The terms used in this disclosure are for the description of specific embodiments and are not intended to limit the claims. As used in the description of embodiments and in the appended claims, the singular form is intended to include the plural form unless the context clearly indicates otherwise. The term "and / or" as used in this disclosure may refer to any one of the related enumerated items, or refers to and includes any and all possible combinations of two or more of them. Additionally, the " / " between words in this disclosure has the same meaning as "and / or" unless otherwise noted.

[0034] The embodiments of the present disclosure may be applied to various wireless communication systems. For example, the embodiments of the present disclosure may be applied to wireless LAN systems. For example, the embodiments of the present disclosure may be applied to wireless LANs based on IEEE 802.11a / g / n / ac / ax / be standards. Furthermore, the embodiments of the present disclosure may be applied to wireless LANs based on newly proposed IEEE 802.11bn (or UHR) standards. Additionally, the embodiments of the present disclosure may be applied to wireless LANs based on next-generation standards following IEEE 802.11bn. Furthermore, the embodiments of the present disclosure may be applied to cellular wireless communication systems. For example, they may be applied to cellular wireless communication systems based on LTE (Long Term Evolution) series technologies and 5G NR (New Radio) series technologies of 3GPP (3rd Generation Partnership Project) standards.

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

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

[0037] The first device (100) and the second device (200) exemplified in FIG. 1 may be replaced with various terms such as terminal, wireless device, WTRU (Wireless Transmit Receive Unit), UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), MSS (Mobile Subscriber Unit), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), or simply user. Additionally, the first device (100) and the second device (200) may be replaced with various terms such as access point (AP), 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.

[0038] The device (100, 200) exemplified in FIG. 1 may be referred to as a station (STA). For example, the device (100, 200) exemplified in FIG. 1 may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, or a receiving STA. For example, the STA (110, 200) may perform the role of an access point (AP) or a non-AP. That is, in the present disclosure, the STA (110, 200) may perform the functions of an AP and / or a non-AP. If the STA (110, 200) performs the AP function, it may simply be referred to as an AP, and if the STA (110, 200) performs the non-AP function, it may simply be referred to as a STA. Additionally, in the present disclosure, the AP may also be indicated as an AP STA.

[0039] Referring to FIG. 1, the first device (100) and the second device (200) can transmit and receive wireless signals through various wireless LAN technologies (e.g., IEEE 802.11 series). The first device (100) and the second device (200) may include interfaces for the medium access control (MAC) layer and the physical layer (PHY) that comply with the specifications of the IEEE 802.11 standard.

[0040] In addition, the first device (100) and the second device (200) may additionally support various communication standards other than wireless LAN technology (e.g., 3GPP LTE series, 5G NR series standards, etc.). In addition, the device of the present disclosure may be implemented as various devices such as mobile phones, vehicles, personal computers, AR (Augmented Reality) equipment, VR (Virtual Reality) equipment, etc. Furthermore, the STA of the present specification may support various communication services such as voice calls, video calls, data communication, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).

[0041] The first device (100) includes one or more processors (102) and one or more memories (104), and may additionally include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memory (104) and / or transceivers (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (102) may process information within the memory (104) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through the transceiver (106) and then store information obtained from the signal processing of the second information / signal in the memory (104). Memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, memory (104) may store software code including instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this disclosure. Here, the processor (102) and memory (104) may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals through one or more antennas (108). The transceiver (106) may include a transmitter and / or receiver. The transceiver (106) may be combined with an RF (Radio Frequency) unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0042] The second device (200) includes one or more processors (202) and one or more memories (204), and may additionally include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memory (204) and / or transceivers (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this disclosure. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be used in combination with an RF unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0043] Hereinafter, hardware elements of the device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure. One or more processors (102, 202) may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this disclosure and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., a baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this disclosure.

[0044] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0045] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0046] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of the present disclosure to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., disclosed in the present disclosure from one or more other devices. For example, one or more transceivers (106, 206) may be connected to one or more processors (102, 202) and may transmit and receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure through one or more antennas (108, 208). In this disclosure, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0047] For example, one of the STAs (100, 200) may perform the intended operation of an AP, and the other of the STAs (100, 200) may perform the intended operation of a non-AP STA. For example, the transceiver (106, 206) of FIG. 1 may perform the operation of transmitting and receiving signals (e.g., packets or PPDU (Physical Layer Protocol Data Unit) according to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). Additionally, the operation of generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals by various STAs in the present disclosure may be performed by the processor (102, 202) of FIG. 1. For example, an example of an operation to generate a transmission and reception signal or to perform data processing or operations in advance for a transmission and reception signal may include: 1) an operation to determine / acquire / configure / operate / decode / encode bit information of fields (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in the PPDU; 2) an operation to determine / configure / acquire time resources or frequency resources (e.g., subcarrier resources) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 3) an operation to determine / configure / acquire specific sequences (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 4) power control operations and / or power saving operations applied to the STA; and 5) operations related to determining / acquiring / configuring / operating / decoding / encoding of an ACK signal. In addition, 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.

[0048] In the following, the downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs, packets, signals, etc., can be transmitted and received through the downlink. In downlink communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. The uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs, packets, signals, etc., can be transmitted and received through the uplink. In uplink communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

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

[0050] The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports STA mobility transparent to the upper layer can be provided. A Basic Service Set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 exemplarily illustrates the existence of two BSSs (BSS1 and BSS2) and the inclusion of two STAs as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). In Figure 2, the ellipse representing the BSS can also be understood as representing the coverage area where the STAs included in the corresponding BSS maintain communication. This area can be referred to as a Basic Service Area (BSA). If a STA moves outside the BSA, it becomes unable to communicate directly with other STAs within that BSA.

[0051] Excluding the DS illustrated in Fig. 2, the most basic type of BSS in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For instance, assuming other components are omitted, a BSS1 composed of only STA1 and STA2, or a BSS2 composed of only STA3 and STA4, can each be considered a representative example of an IBSS. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, this type of wireless LAN is not configured through pre-planning but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. In other words, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and since connections to distributed systems (DS) are not allowed, they form a self-contained network.

[0052] The membership of an STA in a BSS can be dynamically changed by the STA being turned on or off, or by the STA entering or leaving the BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, an STA must be associated with the BSS. This association can be configured dynamically and may include the use of a Distribution System Service (DSS).

[0053] In a wireless LAN, the direct STA-to-STA distance may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in others, communication between STAs over longer distances may be required. To support extended coverage, a distributed system (DS) may be configured.

[0054] DS refers to a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component in an extended form of a network composed of multiple BSSs. DS is a logical concept and can be specified by the characteristics of the Distributed System Medium (DSM). In this regard, the Wireless Medium (WM) and the DSM can be logically distinguished. Each logical medium is used for a different purpose and is utilized by different components. These media are not limited to being identical or different. The flexibility of the wireless LAN structure (DS structure or other network structure) can be explained by the fact that multiple media are logically distinct in this way. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be specified independently by the physical characteristics of each implementation.

[0055] DS can support mobile devices by providing seamless integration of multiple BSSs and providing logical services necessary for handling addresses to destinations. Additionally, DS may include a component called a portal that acts as a bridge for connecting the wireless LAN with another network (e.g., IEEE 802.X).

[0056] An AP refers to an entity that enables access to the DS via the WM for combined non-AP STAs and also possesses the functionality of an STA. Data movement between the BSS and the 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 the DS. Furthermore, since all APs fundamentally correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM and the address used by the AP for communication on the DSM do not necessarily have to be the same. A BSS composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0057] Data transmitted from one of the STA(s) coupled to the AP to the STA address of the AP can always be received at an uncontrolled port and processed by an IEEE 802.1X port access entity. Additionally, if the controlled port is authenticated, the transmitted data (or frame) can be forwarded to the DS.

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

[0059] An ESS refers to a network of arbitrary size and complexity composed of DSs and BSSs. An ESS can correspond to a set of BSSs connected to a single DS. However, an ESS does not contain a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in a single ESS can have the same Service Set Identification (SSID). The SSID is distinct from the BSSID, which is the identifier for the BSS.

[0060] In wireless LAN systems, no assumptions are made regarding the relative physical locations of BSSs, and all of the following forms are possible. BSSs may partially overlap, which is a form commonly used to provide continuous coverage. Additionally, BSSs may not be physically connected, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs may be located in the same physical location, which can be used to provide redundancy. Also, one (or more) IBSS or ESS networks may physically exist in the same space as one (or more) ESS networks. This may apply to ESS network forms such as when an ad-hoc network operates at a location where an ESS network exists, when wireless networks that physically overlap are configured by different organizations, or when two or more different access and security policies are required at the same location.

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

[0062] In order for an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and go through authentication procedures for security. The link setup process can also be referred to as the session initiation process or the session setup process. Additionally, the processes of discovery, authentication, association, and security setup in the link setup process can be collectively referred to as the association process.

[0063] In step S310, the STA may perform a network discovery operation. The network discovery operation may include the STA's scanning operation. That is, in order for the STA to access a network, it must find a network it can join. Before joining a wireless network, the STA must identify a compatible network, and the process of identifying networks existing in a specific area is called scanning.

[0064] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, the STA performing the scanning moves between channels to search for nearby APs, transmits a probe request frame, and waits for a response. The responder transmits a probe response frame as a response to the probe request frame to the STA that transmitted the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame from the BSS of the channel being scanned. In a BSS, the AP becomes the responder because it transmits the beacon frame; however, in an IBSS, the responder is not constant because STAs within the IBSS take turns transmitting the beacon frame. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning in the same way (i.e., transmit and receive probe request / response on channel 2).

[0065] Although not illustrated in FIG. 3, the scanning operation may be performed using a passive scanning method. In passive scanning, the STA performing the scanning waits for a beacon frame while switching between channels. A beacon frame is one of the management frames defined in IEEE 802.11, which is periodically transmitted to announce the presence of a wireless network and to allow the scanning STA to find the wireless network and join it. In a BSS, the AP performs the role of periodically transmitting beacon frames, and in an IBSS, the STAs within the IBSS take turns transmitting beacon frames. When the scanning STA receives a beacon frame, it stores the information about the BSS included in the beacon frame and records the beacon frame information in each channel while moving to another channel. The STA that receives the beacon frame stores the BSS-related information included in the received beacon frame and moves to the next channel, and can perform scanning in the next channel in the same way. When comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0066] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation in step S340 described later.

[0067] The authentication process involves the STA sending an authentication request frame to the AP, and the AP sending an authentication response frame to the STA in response. The authentication frame used in the authentication request / response corresponds to a management frame.

[0068] The authentication frame may include information regarding the authentication algorithm number, authentication transaction sequence number, status code, challenge text, Robust Security Network (RSN), Finite Cyclic Group, etc. These are some examples of information that may be included in the authentication request / response frame, and they may be replaced with other information or additional information may be included.

[0069] The STA can send an authentication request frame to the AP. Based on the information contained in the received authentication request frame, the AP can determine whether to allow authentication for the STA. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0070] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the STA transmitting an association request frame to the AP, and in response, the AP transmitting an association response frame to the STA.

[0071] For example, the association request frame may include information regarding various capabilities, beacon listen interval, service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information regarding various capabilities, status code, Association ID (AID), supported rates, Enhanced Distributed Channel Access (EDCA) parameter set, Received Channel Power Indicator (RCPI), Received Signal to Noise Indicator (RSNI), mobility domain, timeout interval (e.g., association comeback time), overlapping BSS scan parameters, TIM broadcast response, Quality of Service (QoS) map, etc. These are some examples of information that may be included in a combined request / response frame, and may be replaced with other information or additional information may be included.

[0072] After the STA is successfully joined to the network, a security setup process can be performed in step S340. The security setup process in step S340 may be described as an authentication process through RSNA (Robust Security Network Association) requests / responses, and the authentication process in step S320 may be referred to as the first authentication process, and the security setup process in step S340 may simply be referred to as the authentication process.

[0073] The security setup process of step S340 may include, for example, a private key setup process through a 4-way handshake via an EAPOL (Extensible Authentication Protocol over LAN) frame. Additionally, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

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

[0075] In wireless LAN systems, the basic access mechanism for MAC (Medium Access Control) is the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism is also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, and it basically employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA may perform Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time interval (e.g., DIFS (DCF Inter-Frame Space)) before starting transmission. If the sensing result determines that the medium is in an idle status, it starts transmitting a frame through that medium. On the other hand, if the medium is detected to be occupied or busy, the AP and / or STA may not start its own transmission but wait by setting a delay period for medium access (e.g., a random backoff period) before attempting to transmit a frame. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

[0076] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). The HCF is based on the aforementioned Point Coordination Function (PCF). The PCF is a polling-based synchronous access method that periodically polls to ensure all receiving APs and / or STAs can receive data frames. Furthermore, the HCF includes Enhanced Distributed Channel Access (EDCA) and Controlled Channel Access (HCCA). EDCA is a contention-based access method for a provider to offer data frames to multiple users, while HCCA uses a non-contention-based channel access method utilizing a polling mechanism. Additionally, the HCF includes a media access mechanism to improve the Quality of Service (QoS) of the wireless LAN and can transmit QoS data during both the Contention Period (CP) and the Contention-Free Period (CFP).

[0077] Referring to FIG. 4, the operation based on the random backoff period is described. When a medium in an occupied / busy state changes to an idle state, multiple STAs may attempt to transmit data (or frames). As a measure to minimize collisions, each STA may select a random backoff count and attempt transmission after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​in the range from 0 to CW. Here, CW is the Contention Window parameter value. The CW parameter is given an initial value of CWmin, but in the case of transmission failure (e.g., failure to receive an ACK for a transmitted frame), it may take a value twice that amount. When the CW parameter value becomes CWmax, data transmission may be attempted while maintaining the CWmax value until data transmission is successful; if data transmission is successful, it is reset to the CWmin value. The values ​​of CW, CWmin, and CWmax are 2 n It is desirable to set it to -1 (n=0, 1, 2, ...).

[0078] When the random backoff process begins, the STA continues to monitor the media while counting down the backoff slots according to the determined backoff count value. When the media is monitored as occupied, it stops the countdown and waits, and when the media becomes idle, it resumes the remaining countdown.

[0079] In the example of Fig. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 confirms that the medium is idle for DIFS and can immediately transmit the frame. The remaining STAs monitor whether the medium is occupied or busy and wait. Meanwhile, data to be transmitted may also arise from each of STA1, STA2, and STA5, and each STA can perform a countdown of the backoff slot according to a random backoff count value selected by each after waiting for DIFS when the medium is monitored to be idle. Assume the case where STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. That is, this exemplifies a case where, at the point when STA2 finishes the backoff count and starts transmitting the frame, the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1. STA1 and STA5 pause the countdown briefly and wait while STA2 occupies the medium. When STA2's possession ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the paused backoff count. That is, they can start transmitting a frame after counting down the remaining backoff slots corresponding to the remaining backoff time. Since STA5's remaining backoff time was shorter than STA1's, STA5 starts transmitting the frame. While STA2 is occupying the medium, data to be transmitted may also be generated by STA4. From STA4's perspective, when the medium becomes idle, it waits for DIFS, performs a countdown based on a random backoff count value selected by itself, and can start transmitting a frame. The example in Figure 4 illustrates a case where STA5's remaining backoff time happens to match STA4's random backoff count value; in this case, a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 receives an ACK, resulting in a failure to transmit data.In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. STA1 waits while the medium is occupied due to transmission by STA4 and STA5, and when the medium becomes idle, it waits for DIFS, and then can start transmitting frames after the remaining backoff time has passed.

[0080] As shown in the example in Fig. 4, a data frame is a frame used for transmitting data that is forwarded to an upper layer, and can be transmitted after a backoff performed after the elapsed time of DIFS from when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information that is not forwarded to an upper layer, and is transmitted after a backoff performed after the elapsed time of an IFS such as DIFS or PIFS (Point coordination function IFS). Subtypes of management frames include Beacon, Association request / response, re-association request / response, probe request / response, and authentication request / response. A control frame is a frame used to control access to the medium. Subtype frames of control frames include RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), NDP Announcement (null data packet announcement), and Trigger. If a control frame is not an acknowledgment frame of a previous frame, it is transmitted after a backoff performed after the elapsed DIFS; if it is an acknowledgment frame of a previous frame, it is transmitted after the elapsed SIFS (short IFS) without a backoff. The type and subtype of a frame can be identified by the type field and subtype field within the Frame Control (FC) field.

[0081] A QoS (Quality of Service) STA can transmit a frame after backoff, which is performed after the passage of the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC). Here, the frame for which AIFS[i] can be used can be a data frame or a management frame, and can also be a control frame rather than a response frame.

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

[0083] As previously mentioned, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, where the STA directly senses the medium. Virtual carrier sensing is intended to mitigate problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the STA's MAC can utilize the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available, provided that the STA currently using or authorized to use the medium is using it. Therefore, the value set as the NAV corresponds to the period during which the medium is scheduled to be used by the STA transmitting the frame, and the STA receiving the NAV value is prohibited from accessing the medium during that period. For example, the NAV can be set based on the value of the "duration" field in the frame's MAC header.

[0084] In the example of FIG. 5, it is assumed that STA1 intends to transmit data to STA2, and STA3 is located in a position where it can overhear part or all of the frames transmitted and received between STA1 and STA2.

[0085] In order to reduce the possibility of collisions between multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism utilizing RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA1 may be a hidden node to STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA2 may be a hidden node to STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, it is possible to prevent a STA outside the transmission range of either STA1 or STA2, or a STA outside the carrier sensing range for transmission from STA1 or STA3, from attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0086] Specifically, STA1 can determine whether the channel is in use through carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy magnitude or signal correlation detected in the channel. Additionally, in terms of virtual carrier sensing, STA1 can determine the channel occupancy state using a NAV (network allocation vector) timer.

[0087] If the channel is idle during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. If STA2 receives the RTS frame, it can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0088] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) using the duration information included in the RTS frame. Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + data frame + SIFS + ACK frame) using the duration information included in the CTS frame. That is, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, it can set a NAV accordingly. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0089] If STA1 receives a CTS frame from STA2, it may transmit a data frame to STA2 after SIFS from the time the reception of the CTS frame is completed. If STA2 successfully receives the data frame, it may transmit an ACK frame to STA1 as an acknowledgment to the data frame after SIFS. STA3 may determine whether the channel is in use through carrier sensing when the NAV timer expires. If STA3 determines that the channel is not in use by another terminal during DIFS from the time the NAV timer expires, it may attempt channel access after a contention window (CW) based on random backoff has passed.

[0090] FIG. 6 is a drawing for illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure may be applied.

[0091] Based on instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MPDU (MAC PDU) to be transmitted. For example, upon receiving an instruction from the MAC layer requesting the start of transmission, the PHY layer switches to transmit mode and can construct the information provided by the MAC layer (e.g., data) into a frame for transmission. Additionally, if the PHY layer detects a valid preamble of a received frame, it monitors the preamble header and sends an instruction to the MAC layer indicating the start of reception.

[0092] As such, information transmission and reception in wireless LAN systems are carried out in the form of frames, and for this purpose, the Physical Layer Protocol Data Unit (PPDU) format is defined.

[0093] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIGNAL) field, and a Data field. The most basic (e.g., the non-HT (High Throughput)) PPDU format illustrated in FIG. 7 may consist only of Legacy-STF (Legacy-STF), Legacy-LTF (Legacy-LTF), Legacy-SIG (Legacy-SIG) fields and a Data field. In addition, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or other types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF, (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the data field. More specific details will be described later with reference to FIG. 7.

[0094] STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, and precise time synchronization, while LTF is a signal for channel estimation and frequency error estimation. STF and LTF can be considered signals for synchronization and channel estimation in the OFDM physical layer.

[0095] The SIG field may contain various information related to the transmission and reception of the PPDU. For example, the L-SIG field consists of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may contain information regarding the modulation and coding rates of the data. For example, the 12-bit Length field may contain information regarding the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of the PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDUs, the value of the Length field may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0096] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), and PPDU TAIL bits, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiver. The PSDU corresponds to a MAC PDU defined at the MAC layer and may contain data generated or used by the upper layer. The PPDU TAIL bits may be used to return the encoder to a 0 state. Padding bits may be used to adjust the length of the data field to a predetermined unit.

[0097] A MAC PDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). A MAC frame is composed of a MAC PDU and can be transmitted or received through the PSDU of the data portion in the PPDU format.

[0098] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may contain control information necessary for transmitting or receiving frames. The Duration / ID field may be set as the time for transmitting the corresponding frame. Address subfields may indicate the frame's receiver address, transmitter address, destination address, and source address, and some address subfields may be omitted. Specific details regarding each subfield of the MAC header, including Sequence Control, QoS Control, and HT Control subfields, can be found in the IEEE 802.11 standard document.

[0099] The Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP is a frame format that includes the PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and additionally, non-legacy SIG, non-legacy STF, and non-legacy LTF if present) from a standard PPDU format, but excludes the remaining parts (i.e., the data field).

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

[0101] Various forms of PPDU have been used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format may also be referred to as the non-HT PPDU format (Fig. 7(a)).

[0102] The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format illustrated in FIG. 7(b) may be referred to as the HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field, without including L-STF, L-LTF, and L-SIG (not shown).

[0103] An example of the VHT PPDU format (IEEE 802.11ac) includes the VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).

[0104] An example of the HE PPDU format (IEEE 802.11ax) includes the RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in addition to the basic PPDU format (Fig. 7(d)). Depending on specific examples of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multiple users (MU), but is not included in the HE PPDU format for single users (SU). Additionally, the HE trigger-based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field may vary to 8 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.

[0105] The EHT PPDU format may include the EHT MU (multi-user) of FIG. 7(e) and the EHT TB (trigger-based) PPDU of FIG. 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes RL-SIG following L-SIG, but it may include U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following RL-SIG.

[0106] The EHT MU PPDU of FIG. 7(e) corresponds to a PPDU that carries one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0107] The EHT-SIG is omitted in the EHT TB PPDU of FIG. 7(f) compared to the EHT MU PPDU. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0108] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated so that demodulation and decoding can be attempted even on legacy STAs, and mapped based on a defined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated so that they can be demodulated and decoded by a STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) to obtain the information contained in the corresponding fields, and mapped based on a defined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0109] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulation fields. Also, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as pre-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0110] The U-SIG included in the EHT PPDU format of FIG. 7 can be constructed based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol for the U-SIG (e.g., OFDM symbol) can have a duration of 4 µs, and the U-SIG can have a total duration of 8 µs. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0111] U-SIGs can be configured in 20 MHz units. For example, if an 80 MHz PPDU is configured, the same U-SIG can be duplicated in 20 MHz units. That is, four identical U-SIGs can be included within an 80 MHz PPDU. If the bandwidth exceeds 80 MHz, for example, for a 160 MHz PPDU, the U-SIG of the first 80 MHz unit and the U-SIG of the second 80 MHz unit may be different.

[0112] For example, A number of uncoded bits may be transmitted through U-SIG, and the first symbol of U-SIG (e.g., U-SIG-1 symbol) transmits the first X bits of the total A bit information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) transmits the remaining Y bits of the total A bit information. The A bit information (e.g., 52 uncoded bits) may include a CRC field (e.g., a field of 4 bits) and a tail field (e.g., a field of 6 bits). The tail field may be used to terminate the trellis of the convolution decoder and may be set to, for example, 0.

[0113] A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG may be included in a new PPDU format not shown in FIG. 7 (e.g., UHR PPDU format), and in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, and some or all of the version-dependent bits may be different.

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

[0115] For example, the version-independent bits of U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version of the transmitted / received PPDU (e.g., EHT, UHR, etc.). The version-independent bits of U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value of the UL / DL flag field relates to DL communication. The version-independent bits of U-SIG may include information regarding the length of the TXOP (transmission opportunity) and information regarding the BSS color ID.

[0116] For example, the version-dependent bits of U-SIG may contain information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0117] Information necessary for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information regarding bandwidth, information regarding MCS techniques applied to non-legacy SIGs (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether DCM (dual carrier modulation) techniques (e.g., techniques to achieve an effect similar to frequency diversity by reusing the same signal on two subcarriers) are applied to non-legacy SIGs, information regarding the number of symbols used for non-legacy SIGs, and information regarding whether non-legacy SIGs are generated across the entire band.

[0118] Some of the information required for PPDU transmission and reception may be included in U-SIG and / or non-legacy SIGs (e.g., EHT-SIG or UHR-SIG, etc.). For example, information regarding the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information regarding the length of non-legacy LTF and cyclic prefix (CP) length, information regarding guard interval (GI) applied to non-legacy LTF, information regarding preamble puncturing applicable to PPDU, information regarding resource unit (RU) allocation, etc., may be included only in U-SIG, may be included only in non-legacy SIG, or may be indicated by a combination of information included in U-SIG and information included in non-legacy SIG.

[0119] Preamble puncturing may refer to the transmission of a PPDU in which a signal is not present in one or more frequency units within the PPDU bandwidth. For example, the size of the frequency unit (or the resolution of preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or larger.

[0120] In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. A non-legacy SIG may be transmitted through at least one symbol, and one symbol may have a length of 4 µs. Information regarding the number of symbols used for EHT-SIG may be included in the previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0121] Non-legacy SIGs, such as HE-SIG-B and EHT-SIG, may include common fields and user-specific fields. Common fields and user-specific fields may be coded individually.

[0122] In some cases, the common field may be omitted. For example, in a compression mode where non-OFDMA (orthogonal frequency multiple access) is applied, the common field may be omitted, and multiple STAs may receive PPDUs (e.g., the data field of the PPDU) over the same frequency band. In a non-compression mode where OFDMA is applied, multiple users may receive PPDUs (e.g., the data field of the PPDU) over different frequency bands.

[0123] The number of user-specific fields can be determined based on the number of users. A single user block field can contain up to two user fields. Each user field may be related to MU-MIMO allocation or non-MU-MIMO allocation.

[0124] The common field may include CRC bits and Tail bits, the length of the CRC bits may be determined to be 4 bits, and the length of the Tail bits may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information regarding the location of the RU to which a plurality of users (i.e., a plurality of receiving STAs) are allocated.

[0125] An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on the OFDMA technique. Additionally, an RU may be defined when transmitting signals to a single STA. Resources may be allocated on an RU basis for non-legacy STF, non-legacy LTF, and Data fields.

[0126] Applicable RU sizes can be defined according to the PPDU bandwidth. RUs may be defined identically or differently for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU placement for HE PPDU and EHT PPDU may differ. The applicable RU sizes, number of RUs, RU locations, DC (direct current) subcarrier locations and numbers, null subcarrier locations and numbers, and guard subcarrier locations and numbers for each PPDU bandwidth can be referred to as a tone-plan. For example, a tone-plan for a wide bandwidth may be defined as a multiple repetition of a tone-plan for a low bandwidth.

[0127] RUs of various sizes can be defined as 26-ton RUs, 52-ton RUs, 106-ton RUs, 242-ton RUs, 484-ton RUs, 996-ton RUs, 2x996-ton RUs, 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.

[0128] The specific size of the RU may be reduced or expanded. Accordingly, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not limited and is exemplary. Additionally, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) in this disclosure, the number of RUs may vary depending on the RU size.

[0129] The names of the respective fields in the PPDU formats of FIG. 7 are exemplary and the scope of the present disclosure is not limited by such names. Furthermore, the examples of the present disclosure may be applied not only to the PPDU formats exemplified in FIG. 7, but also to new PPDU formats based on the PPDU formats of FIG. 7 in which some fields are excluded and / or some fields are added.

[0130] EHT-SIG field

[0131] 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.

[0132] Figure 8 shows an exemplary structure of the EHT-SIG content channel.

[0133] Figure 8 illustrates an EHT-SIG content channel format for OFDMA transmission when the bandwidth is 20 / 40 / 80 MHz.

[0134] As shown in Fig. 8, each EHT-SIG content channel can be composed of common fields and user-specific fields.

[0135] Here, the common field may include one or two RU allocation subfields depending on the PPDU frequency bandwidth.

[0136] 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.

[0137] Table 1 illustrates common fields for OFDMA transmission.

[0138]

[0139]

[0140]

[0141] In non-OFDMA transmission, the common field of the EHT-SIG content channel may not include the RU allocation subfield.

[0142] 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).

[0143] 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).

[0144] 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.

[0145] 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.

[0146] Table 2 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.

[0147]

[0148]

[0149]

[0150]

[0151]

[0152] Referring to Table 2, 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 + 2 1 × y1 + y0 + 1 indicates a user field.

[0153] In Table 2, 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.

[0154] In Table 2, 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.

[0155] Table 3 illustrates the RUs or MRUs associated with each RU allocation subfield for each EHT-SIG content channel and PPDU bandwidth.

[0156]

[0157]

[0158] Table 4 shows the indices of null subcarriers for each RU size when the channel bandwidth is 20 MHz and 40 MHz.

[0159]

[0160] Table 5 shows the indices of null subcarriers for each RU size when the channel bandwidth is 80 MHz, 160 MHz, and 320 MHz.

[0161]

[0162] Table 6 illustrates common fields for EHT SU transmission and non-OFDMA transmission to multiple users.

[0163]

[0164]

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] Table 7 shows examples of user field formats for non-MU-MIMO allocation.

[0170]

[0171]

[0172] Table 8 shows examples of user field formats for MU-MIMO allocation.

[0173]

[0174] PPDU transmission and reception method for coordinated transmission

[0175] Multi-AP transmission technology is a new wireless transmission technology to be defined in next-generation wireless LAN systems (e.g., Wi-Fi 8, 802.11bn). Among these, Coordinated Beamforming (Co-BF) transmission is a Multi-AP cooperative technology that can increase the transmission rate by allowing two APs to transmit frames simultaneously. In other words, Coordinated Beamforming enables two APs with multiple antennas to transmit simultaneously to non-AP STAs connected to each of the two APs. Here, each AP transmits PPDU to connected non-AP STAs within its Baseline Service (BSS). Here, by using information about the channel between each AP and the receiving STA of the other AP in the Co-BF transmission, interference to the non-AP STA(s) connected to the other AP can be minimized.

[0176] In particular, for Co-BF transmission, simultaneous transmission is smoothly supported by controlling interference through precoding for STAs where the signal-to-noise ratio (SNR) values ​​from the two APs do not differ significantly. This is because coordinated spatial reuse (Co-SR) technology, which can be relatively inexpensive to implement, may be more advantageous in situations where there is a large difference in SNR values.

[0177] When transmitting Co-BF signals / PPDUs to STAs with similar SNR values, preamble collision issues may occur. If the pre-UHR part preambles of the Co-BF PPDUs transmitted by two APs convey different information, the receiving STA may not be able to properly decode the SIG field transmitted to it. To prevent this problem, discussions on standard technology are underway to design the pre-UHR portion of the Co-BF PPDU's PHY preamble to be common to both APs. While the aforementioned problem might not occur if beamforming were applied to the legacy part as well, the 11bn standard conference decided not to apply beamforming to the legacy part.

[0178] In addition, Coordinated Spatial Reuse (Co-SR) technology is attracting attention as one of the multi-AP cooperation technologies that enables simultaneous transmission by multiple APs, thereby improving system performance such as throughput and latency. In other words, Coordinated Spatial Reuse (Co-SR) allows for more efficient media usage by transmitting simultaneously from multiple APs using transmission power control. Here, each AP can transmit PPDU to an associated non-AP STA within its BSS.

[0179] The core of Co-SR may be interference management, and simultaneous transmission implies that the transmissions from both APs can act as mutual interference. Therefore, it may be desirable to select an STA that ensures the transmissions from each AP cause sufficiently small interference to each other, and furthermore, setting an appropriate power can lead to superior performance in terms of throughput and latency.

[0180] If each AP designs the preamble of a Co-SR PPDU separately, a simple design would be possible, but conflicts in the signaling fields of the two Co-SR PPDUs would occur, leading to degraded decoding performance. To prevent this problem in advance, discussions are underway to design the preamble field in common.

[0181] The present disclosure proposes a method for designing / configuring a common preamble (e.g., UHR-SIG) of a PPDU for cooperative transmission (e.g., Co-BF or Co-SR).

[0182] If a common preamble (e.g., UHR-SIG) is to be designed, all parameters to be transmitted by the two APs must be contained in a single preamble. Accordingly, the present disclosure proposes a method for transmitting parameters to be transmitted by the two APs by including them in a single common preamble (e.g., UHR-SIG).

[0183] In addition, all user fields for two BSSs can be transmitted in a single common preamble (e.g., UHR-SIG), and a method is required to indicate which BSS each user field corresponds to. Otherwise, a collision may occur if the STA-ID intended for service by two BSSs happens to be the same.

[0184] A signaling method is being discussed in which 1 bit is allocated to each user field, so that BSS 1 is assigned when 0 and BSS 2 is assigned when 1, but this requires transmitting a 1-bit signal in all user fields, resulting in overhead equal to the number of user fields.

[0185] Accordingly, the present disclosure proposes a method for indicating the number of users of BSS1 in a common field (e.g., using 1 bit) without additional signaling for AP / BSS distinction in the user field. For example, if the maximum number of STAs per AP in Co-BF transmission is limited to 2, the number of users of BSS1 can be indicated with only 1 bit. According to the method proposed in the present disclosure, since it is sufficient to use only a bit (e.g., 1 bit) in the common field, it is not necessary to have as many bits as the number of user fields, thereby reducing signaling overhead.

[0186] Hereinafter, an AP that secures a TXOP for operation / transmission of Co-coordinated beamforming (Co-BF) and / or Co-coordinated spatial reuse (Co-SR) and transmits a frame / signaling for an invitation / request to another AP may be referred to as a (Co-BF) coordinating AP, sharing AP, master AP, primary AP, etc., and may be referred to as the first AP (AP 1) for convenience of explanation in the description of the present disclosure below. Additionally, an AP that receives a frame / signaling for an invitation / request for Co-BF operation / transmission may be referred to as a (Co-BF) coordinated AP, shared AP, slave AP, secondary AP, etc., and may be referred to as the second AP (AP 2) for convenience of explanation in the description of the present disclosure below.

[0187] Example 1

[0188] Method 1: Within a common preamble (e.g., UHR-SIG) of a PPDU for cooperative transmission, the number of non-OFDMA users for a first AP (e.g., coordinating AP, sharing AP) and a second AP (e.g., coordinated AP, shared AP) may each be indicated.

[0189] When applying a method that indicates the sum of non-OFDMA users considered by two APs, an additional 1 bit is used in the user field for BSS color indication to indicate which of the two APs each user field corresponds to the STA. Consequently, since an additional 1-bit field is consumed for each user field, there is a problem of signaling overhead.

[0190] On the other hand, according to the proposed method of the present embodiment, the number of non-OFDMA users for the first AP (e.g., coordinating AP, sharing AP) and the second AP (e.g., coordinated AP, shared AP) can be indicated respectively. According to the proposed method, since it is possible to determine which user field from the beginning among a plurality of user fields is a user field for the STA associated with the first AP (e.g., coordinating AP, sharing AP), a 1-bit BSS color indication within each user field is unnecessary.

[0191] However, if a preamble (e.g., UHR-SIG) is designed in this form, it is necessary to redesign the spatial configuration (field) existing in the user field. The current spatial configuration (field) has a structure in which the number of spatial streams is allocated in descending order starting from the STA allocated first. However, if this structure is applied as is, the STAs of the second AP are always allocated to the latter part of the user field (i.e., the user field is located after the STA of the first AP), so fewer spatial streams will inevitably be allocated.

[0192] Specifically, the design method for the spatial configuration (field) is described.

[0193] According to the present disclosure, one of the various types of spatial settings (fields) exemplified below may be used in the preamble of a PPDU for cooperative transmission, and one of the various types of spatial settings (fields) may also be dynamically selected and used due to the AP settings, the number of total spatial streams, or the total number of users.

[0194] - Type 1 space settings

[0195] The configuration method of the existing space setting subfield can be used in the same way. For example, the configuration method of the 4-bit space setting subfield defined in 802.11ax as shown in Table 9 below can be used in the same way.

[0196] Table 9 shows examples of encoding for space setting subfields.

[0197]

[0198] However, in Type 1 space configuration, the STA to which space streams are allocated first is allocated a number of space streams equal to or greater than that of subsequent STAs. For example, N STS [1] is always N STS [2] is equal to or greater than N STS [2] is always N STS [3] The restriction that it is equal to or greater than that applies to the others as well.

[0199] - Type 2 space settings

[0200] Assuming that the maximum total number of users supported for cooperative transmission is 4 and the maximum number of space streams for each STA is 2, the possible space configurations are as shown in Table 10 below. Type 2 space configurations can be applied in situations where BSS color indications are applied. Referring to Table 10 below, since the maximum number of entries is 3, Type 2 space configurations can be indicated by 2 bits.

[0201]

[0202] That is, this Type 2 space configuration can reduce signaling overhead compared to Type 1 space configuration by excluding unnecessary items, assuming that the maximum total number of users supported for cooperative transmission is 4 and the maximum number of space streams for each STA is 2.

[0203] However, similar to Type 1 space configuration, the STA to which space streams are allocated first is allocated a number of space streams equal to or greater than that of subsequent STAs. For example, N STS [1] is always N STS [2] is equal to or greater than N STS [2] is always N STS [3] is equal to or greater than, and N STS [3] is always N STS [4] The restriction that it is equal to or greater than is applied.

[0204] - Type 3 space settings

[0205] Assuming that the maximum total number of users supported for cooperative transmission is 4 and the maximum number of spatial streams for each STA is 2, the possible spatial configurations are as shown in Table 11 below. Type 3 spatial configurations can be applied in situations where BSS color indications are applied.

[0206] In addition, the Type 3 space configuration can be configured differently from the Type 2 space configuration described above by also taking into account the order of the number of space streams allocated to each STA.

[0207] For example, assume that in a situation where BSS color indication is not used, the user field is configured so that the user field for the STA associated with the first AP (e.g., coordinating AP, sharing AP) is placed first, and the user field for the STA associated with the second AP (e.g., coordinated AP, shared AP) is placed next. In this case, if a Type 2 spatial configuration is applied, a problem arises where a larger number of spatial streams cannot be allocated to the second AP because the number of spatial streams is sorted in descending order. To prevent this problem, a Type 3 spatial configuration can be configured in a form that adds an item for allocating spatial streams sorted in ascending order as well as descending order. Referring to Table 11 below, since the maximum number of items is 4, a Type 3 spatial configuration can be indicated by 2 bits.

[0208]

[0209] Method 2: Within a common preamble (e.g., UHR-SIG) of a PPDU for cooperative transmission, the number of LTFs (e.g., number of UHR-LTFs) for a first AP (e.g., coordinating AP, sharing AP) and a second AP (e.g., coordinated AP, shared AP) may each be indicated.

[0210] While signaling overhead can be reduced by applying a method that specifies the larger of the required UHR-LTF values ​​for the first AP (e.g., coordinating AP, sharing AP) and the second AP (e.g., coordinated AP, shared AP) and allows both APs to apply that LTF value, a problem may arise where unnecessary UHR-LTFs must be transmitted because an AP that would suffice to transmit fewer LTFs requires more LTF transmission. To prevent this, we propose a method of specifying the number of LTFs (e.g., the number of UHR-LTFs) for the first AP and the second AP respectively within the common preamble of the PPDU for cooperative transmission (e.g., within the common field of the UHR-SIG).

[0211] To apply the above-described methods 1 and / or 2, the preamble of the PPDU for cooperative transmission may include the following information / fields. For example, the following information / fields may be included in the common field of the UHR-SIG of the PPDU for cooperative transmission.

[0212] i) Number of non-OFDMA users for the first AP (e.g., coordinating AP, sharing AP)

[0213] This is a field / information indicating the number of non-OFDMA users that the first AP will service (i.e., send PPDUs for cooperative transmission). For example, if the total number of STAs to which two APs send Co-BF PPDUs in cooperative transmission (e.g., Co-BF transmission) is limited to 4, it may be defined as 2 bits to indicate any one of the values ​​1, 2, and 3.

[0214] ii) Number of non-OFDMA users for the second AP (e.g., coordinated AP, shared AP)

[0215] This is a field / information indicating the number of non-OFDMA users that the second AP will service (i.e., send PPDUs for cooperative transmission). For example, if the total number of STAs to which two APs send Co-BF PPDUs in cooperative transmission (e.g., Co-BF transmission) is limited to 4, it may be defined as 2 bits to indicate any one of the values ​​1, 2, and 3.

[0216] iii) Number of LTFs (e.g., UHR-LTF) for the first AP (e.g., coordinating AP, sharing AP)

[0217] This is a field / information indicating the number of LTFs (e.g., UHR-LTF) that the first AP applies to the PPDU for cooperative transmission. For example, if the number of maximum space streams in cooperative transmission (e.g., Co-BF transmission) is limited to 2, it may be defined as 1 bit to indicate either a value of 1 or 2.

[0218] iv) Number of LTFs (e.g., UHR-LTF) for the second AP (e.g., coordinated AP, shared AP)

[0219] This is a field / information indicating the number of LTFs (e.g., UHR-LTF) that the second AP applies to the PPDU for cooperative transmission. For example, if the number of maximum space streams in cooperative transmission (e.g., Co-BF transmission) is limited to 2, it may be defined as 1 bit to indicate either a value of 1 or 2.

[0220] By applying the above-described Method 1 and / or Method 2, the preamble of the PPDU for cooperative transmission may be configured as follows. Hereinafter, for convenience of explanation, the UHR-SIG field within the PPDU for cooperative transmission is described as an example, but the present disclosure is not limited thereto and may be applied to a SIG field defined in a next-generation wireless LAN system other than the UHR-SIG field, or may be applied to other fields of the PPDU preamble other than the SIG field.

[0221] Example 1) This example corresponds to a case where both Method 1 and Method 2 described above are applied.

[0222] FIG. 9 illustrates a non-OFDMA common field of a UHR-SIG field according to one embodiment of the present disclosure.

[0223] Referring to FIG. 9, the non-OFDMA common fields of the UHR-SIG field of the PPDU for cooperative transmission include a spatial reuse subfield, a GI+LTF size subfield, a number of UHR-LTF symbols for the sharing AP (i.e., the first AP or coordinating AP) subfield, a number of UHR-LTF symbols for the shared AP (i.e., the second AP or coordinated AP) subfield, a reserved subfield, an LDPC (low-density parity check) extra symbol segment subfield, a pre-FEC (pre-forward error correction) padding factor subfield, a packet extension (PE) disambiguity subfield, a disregard subfield, and for the sharing AP (i.e., the first AP or coordinating AP). It may be configured to include a subfield of the number of non-OFDMA users for the sharing AP and a subfield of the number of non-OFDMA users for the shared AP (i.e., the second AP or coordinated AP).

[0224] Compared to the non-OFDMA common field of the EHT-SIG field (see Table 6) (or compared to the non-OFDMA common field of the UHR-SIG field), instead of the number of EHT-LTF symbols (or number of UHR-LTF symbols) subfield, i) a subfield of the number of UHR-LTF symbols for the sharing AP (i.e., the first AP or coordinating AP), ii) a subfield of the number of UHR-LTF symbols for the shared AP (i.e., the second AP or coordinated AP), and iii) a reserved subfield may be defined / configured.

[0225] In addition, compared with the non-OFDMA common field of the EHT-SIG field (see Table 6) (or compared with the non-OFDMA common field of the UHR-SIG field), instead of the number of non-OFDMA users subfield, i) a subfield of the number of non-OFDMA users for the sharing AP (i.e., the first AP or coordinating AP), and ii) a subfield of the number of non-OFDMA users for the shared AP (i.e., the second AP or coordinated AP) may be defined / configured.

[0226] The description of fields other than those in Figure 9 is the same as in Table 6, so a detailed description is omitted.

[0227] FIG. 10 illustrates a MU-MIMO user field of a UHR-SIG field according to one embodiment of the present disclosure.

[0228] Referring to FIG. 10, the MU-MIMO user field of the UHR-SIG field of the PPDU for cooperative transmission may be configured to include a STA-ID subfield, an MCS (modulation and codign scheme) subfield, a spatial configuration subfield, a reserved subfield, and a 2xLDPC subfield.

[0229] The spatial configuration subfield may include the spatial configuration described above, for example, a type 1 spatial configuration or a type 3 spatial configuration and a spare bit. Additionally, B21 may be used as a spare bit without using a BSS color indication.

[0230] The 2xLDPC subfield indicates whether a nominal LDPC codeword length of 3888 is used. If the 2xLDPC subfield is 0, it indicates that a nominal LDPC codeword length of 648, 1296, or 1944 is used, and if it is 1, it indicates that a nominal LDPC codeword length of 3888 is used.

[0231] The description of fields other than those in Figure 10 is the same as in Table 8, so a detailed description is omitted.

[0232] Example 2) This example corresponds to the case where only Method 1 described above is applied.

[0233] FIG. 11 illustrates a non-OFDMA common field of a UHR-SIG field according to one embodiment of the present disclosure.

[0234] Referring to FIG. 11, the non-OFDMA common field of the UHR-SIG field of the PPDU for cooperative transmission may be configured to include a spatial reuse subfield, a GI+LTF size subfield, a number of UHR-LTF symbols subfield, a low-density parity check (LDPC) extra symbol segment subfield, a pre-forward error correction (pre-FEC) padding factor subfield, a packet extension (PE) disambiguity subfield, a disregard subfield, a number of non-OFDMA users for the sharing AP (i.e., the first AP or coordinating AP), and a number of non-OFDMA users for the shared AP (i.e., the second AP or coordinated AP).

[0235] Compared to the non-OFDMA common field of the EHT-SIG field (see Table 6) (or compared to the non-OFDMA common field of the UHR-SIG field), instead of the number of non-OFDMA users subfield, i) a subfield of the number of non-OFDMA users for the sharing AP (i.e., the first AP or coordinating AP), and ii) a subfield of the number of non-OFDMA users for the shared AP (i.e., the second AP or coordinated AP) may be defined / configured.

[0236] The description of fields other than those in Fig. 11 is the same as in Table 6, so a detailed description is omitted.

[0237] FIG. 12 illustrates a MU-MIMO user field of a UHR-SIG field according to one embodiment of the present disclosure.

[0238] Referring to FIG. 12, the MU-MIMO user field of the UHR-SIG field of the PPDU for cooperative transmission may be configured to include a STA-ID subfield, an MCS (modulation and codign scheme) subfield, a spatial configuration subfield, a reserved subfield, and a 2xLDPC subfield.

[0239] The spatial configuration subfield may include the spatial configuration described above, for example, a type 1 spatial configuration or a type 3 spatial configuration and a spare bit. Additionally, B21 may be used as a spare bit without using a BSS color indication.

[0240] Example 3) This example corresponds to the case where only Method 2 explained earlier is applied.

[0241] FIG. 13 illustrates a non-OFDMA common field of a UHR-SIG field according to one embodiment of the present disclosure.

[0242] Referring to FIG. 13, the non-OFDMA common fields of the UHR-SIG field of the PPDU for cooperative transmission include a spatial reuse subfield, a GI+LTF size subfield, a number of UHR-LTF symbols for the sharing AP (i.e., the first AP or coordinating AP) subfield, a number of UHR-LTF symbols for the shared AP (i.e., the second AP or coordinated AP) subfield, a reserved subfield, an LDPC (low-density parity check) extra symbol segment subfield, a pre-FEC (pre-forward error correction) padding factor subfield, a packet extension (PE) disambiguity subfield, a disregard subfield, and a number of non-OFDMA users. It can be configured to include subfields.

[0243] Compared to the non-OFDMA common field of the EHT-SIG field (see Table 6) (or compared to the non-OFDMA common field of the UHR-SIG field), instead of the number of EHT-LTF symbols (or number of UHR-LTF symbols) subfield, i) a subfield of the number of UHR-LTF symbols for the sharing AP (i.e., the first AP or coordinating AP), ii) a subfield of the number of UHR-LTF symbols for the shared AP (i.e., the second AP or coordinated AP), and iii) a reserved subfield may be defined / configured.

[0244] The description of fields other than those in Fig. 13 is the same as in Table 6, so a detailed description is omitted.

[0245] FIG. 14 illustrates a MU-MIMO user field of a UHR-SIG field according to one embodiment of the present disclosure.

[0246] Referring to FIG. 14, the MU-MIMO user field of the UHR-SIG field of the PPDU for cooperative transmission may be configured to include a STA-ID subfield, an MCS (modulation and codign scheme) subfield, a spatial configuration subfield, a reserved subfield, a BSS color indication subfield, and a 2xLDPC subfield.

[0247] The spatial configuration subfield may include the spatial configuration described above, for example, a type 1 spatial configuration or a type 2 spatial configuration and a spare bit. Additionally, B21 may be used as a BSS color indicator.

[0248] Example 2

[0249] When designing / configuring a common preamble (e.g., UHR-SIG) of a PPDU for cooperative transmission (e.g., Co-BF or Co-SR), we propose a method to indicate which STAs of the BSS each user field of the common preamble (e.g., UHR-SIG) indicates (or which STA is associated with which AP).

[0250] According to the present embodiment, the number of STAs considered by a first AP (e.g., coordinating AP, sharing AP) within a common preamble of a PPDU for cooperative transmission (e.g., a common field of UHR-SIG) (i.e., the number of STAs to which the first AP transmits a PPDU for cooperative transmission) may be indicated. Alternatively, the number of STAs considered by a second AP (e.g., coordinated AP, shared AP) (i.e., the number of STAs to which the second AP transmits a PPDU for cooperative transmission) may be indicated.

[0251] For example, if the maximum number of STAs supported in cooperative transmission (e.g., Co-BF transmission) is limited to 2, it can be indicated by 1 bit. For example, a value of 0 can indicate that the number of STAs is 1, and a value of 1 can indicate that the number of STAs is 2. However, this is just one example, and if more STAs are supported in cooperative transmission, more bits can be used to indicate the number of STAs considered by the first AP (or the number of STAs considered by the second AP).

[0252] For example, since the total number of users is indicated in the number of non-OFDMA users field within the common field of the UHR-SIG field, if the number of STAs considered by AP 1 is indicated, that number of user fields can be interpreted as user fields for STAs associated with AP 1, and the remaining user fields can be interpreted as user fields for STAs associated with AP 2. That is, for example, when a cooperative transmission (e.g., Co-BF) pre-UHR preamble is designed in common, the number of STAs considered by the first AP (or the second AP) can be indicated within the common field of the common UHR-SIG field.

[0253] Example 3

[0254] A common UHR-SIG can be defined to prevent conflicts in the preamble portions of the PPDUs of two APs that may occur in cooperative transmission (e.g., Co-SR).

[0255] In the following description of the embodiments, Co-SR transmission in a situation where only SU transmission is supported is mainly described for convenience of explanation, but the present disclosure is not limited thereto.

[0256] 1. Non-OFDMA Common Fields

[0257] a) Spatial reuse subfields

[0258] This field is a subfield that performs the same role as the spatial reuse field in the non-OFDMA common fields within EHT-SIG (see Table 6).

[0259] Additionally or alternatively, spatial reuse values ​​for the cooperative transmission PPDU of the first AP and the second AP may be defined separately. For example, a spatial reuse for AP 1 subfield and a spatial reuse for AP 2 subfield may be defined separately.

[0260] b) GI(guard interval)+LTF Size (GI+LTF Size)

[0261] This field indicates the GI+LTF size that can be applied to UHR-LTF.

[0262] Additionally or alternatively, GI+LTF values ​​for the cooperative transmission PPDU of the first AP and the second AP may be defined separately. For example, a GI+LTF Size for AP 1 subfield and a GI+LTF Size for AP 2 subfield may be defined separately.

[0263] c) Number of UHR-LTF Symbols

[0264] This field indicates the symbol number of the UHR-LTF.

[0265] Additionally or alternatively, a field for the number of UHR-LTF symbols for the cooperative transmission PPDU of the first AP and the second AP may be defined separately. For example, a subfield for the number of UHR-LTF symbols for AP 1 and a subfield for the number of UHR-LTF symbols for AP 2 may be defined.

[0266] d) LDPC Extra Symbol Segment

[0267] This field is a subfield that performs the same role as the LDPC Extra Symbol Segment field in the non-OFDMA common fields within EHT-SIG.

[0268] Additionally or alternatively, LDPC Extra Symbol Segment subfields for the cooperative transmission PPDU of the first AP and the second AP may be defined separately. For example, an LDPC Extra Symbol Segment for AP 1 subfield and an LDPC Extra Symbol Segment for AP 2 subfield may be defined separately.

[0269] e) Pre-FEC padding factor

[0270] It is a subfield that performs the same role as the Pre-FEC padding factor field among the non-OFDMA common fields within EHT-SIG.

[0271] Additionally or alternatively, a Pre-FEC padding factor subfield for the cooperative transmission PPDU of the first AP and the second AP may be defined separately. Specifically, a Pre-FEC padding factor for AP 1 subfield and a Pre-FEC padding factor for AP 1 subfield may be defined.

[0272] f) PE Disambiguity

[0273] It is a subfield that performs the same role as the PE Disambiguity field in the non-OFDMA common fields within EHT-SIG.

[0274] Additionally or alternatively, PE Disambiguity for the cooperative transmission PPDU of the first AP and the second AP may be defined separately. For example, a PE Disambiguity for AP 1 subfield and a PE Disambiguity for AP 2 subfield may be defined separately.

[0275] g) Number of non-OFDMA Users

[0276] This is a field indicating the number of non-OFDMA users present in the two APs. For example, if 1 STA is considered for the PPDU of the first AP and 2 STAs are considered for the PPDU of the second AP, the field may indicate 3.

[0277] Additionally or alternatively, a subfield of Number of non-OFDMA Users for the cooperative transmission PPDU of the first AP and the second AP may be defined separately. Specifically, a subfield of Number of non-OFDMA Users for AP 1 and a subfield of Number of non-OFDMA Users for AP 2 may be defined.

[0278] If, under the condition that only SU transmission is allowed for each AP for cooperative transmission, this field may not be necessary (i.e., may not be included).

[0279] For example, the subfields of the aforementioned Non-OFDMA common field can be included in and transmitted within the Non-OFDMA common field in the UHR-SIG of the PPDU for cooperative transmission.

[0280] 2. Non-MU-MIMO User Fields

[0281] a) STA-ID

[0282] This field can indicate the AID11 information of each STA.

[0283] b) MCS

[0284] This field can indicate the MCS information of each STA. For example, in UHR, it can be defined as a 5-bit MCS field.

[0285] c) Nss

[0286] It can indicate the number of space streams for each STA. In UHR, this field can be composed of 3 bits to indicate up to 8 space streams.

[0287] d) Beamformed

[0288] This field indicates whether beamforming has been applied to the PPDU transmission and can be composed of 1 bit.

[0289] e) Coding

[0290] This field indicates whether binary convolutional coding (BCC) or LDPC is applied to the PPDU transmission, and can be composed of 1 bit.

[0291] For example, the subfields of the aforementioned non-MU-MIMO user field may be included in the non-MU-MIMO user field within the user specific field in the UHR-SIG of the PPDU for cooperative transmission and transmitted.

[0292] FIG. 15 is a drawing illustrating a PPDU format according to one embodiment of the present disclosure.

[0293] Referring to FIG. 15, a UHR PPDU that can be used in a UHR system may include some format features of HE TB PPDU and EHT TB PPDU. For example, a UHR PPDU (e.g., UHR TB PPDU) may be configured to include L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-STF, UHR-LTF(s), and data fields.

[0294] In addition, although not shown in FIG. 15, the UHR PPDU (e.g., UHR MU PPDU) may be configured to include an additional UHR SIG between the U-SIG and UHR-STF.

[0295] In FIG. 15, L-STF, L-LTF, and L-SIG may be referred to as legacy parts, RL-SIG, U-SIG, and UHR-SIG (if included) may be referred to as SIG parts, UHR-STF may be referred to as STF parts, and UHR-LTF may be referred to as LTF parts.

[0296] All or part of all parts (i.e., fields) of FIG. 15 may be divided into multiple subparts / subfields. Each field (and its subfields) may be transmitted in units of 4us * N (where N is an integer). Additionally, it may include a Guard Interval (GI) (or short GI) as defined in conventional wireless LAN systems. 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 all of the illustrated fields, or a first delta_f may be applied to the first part (e.g., all of the 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 parts.

[0297] Some of the illustrated fields may be omitted, and the order of the fields is illustrated illustratively and may be changed in various ways.

[0298] The SIG part may include various control information for the transmitted PPDU. For example, it may include an STF part, an LTF part, and control information for decoding the data. For example, it may include all or part of the information included in the previously described HE-SIG-A information, information included in the HE-SIG-B information, information included in the U-SIG information, and information included in the EHT-SIG.

[0299] The STF part may include an STF sequence.

[0300] The LTF part may include a training field (i.e., an LTF sequence) for channel estimation.

[0301] The data field contains user data and may include packets for the upper layer. That is, it may include MPDU (MAC Frame).

[0302] For cooperative transmission (e.g., Co-BF transmission or Co-SR transmission), the first PPDU transmitted by the first AP to the STA(s) connected to it and the second PPDU transmitted by the second AP to the STA(s) connected to it may each be configured in the PPDU format according to FIG. 15 described above, and a common preamble may be constructed for the first PPDU and the second PPDU.

[0303] FIG. 16 illustrates the operation of an AP for a PPDU transmission and reception method for cooperative transmission according to one embodiment of the present disclosure.

[0304] FIG. 16 illustrates the operation of an AP device based on the previously proposed methods. The example in FIG. 13 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 13 may be omitted depending on the situation and / or configuration.

[0305] In the following description, the first AP may correspond to a coordinating AP, a sharing AP, etc., and the second AP may correspond to a coordinated AP, a shred AP, etc. Or conversely, the first AP may correspond to a coordinated AP, a shred AP, etc., and the second AP may correspond to a coordinating AP, a sharing AP, etc.

[0306] The first AP generates the first PPDU for cooperative transmission (S1601).

[0307] Here, the cooperative transmission can be a coordinated spatial reused (Co-SR) transmission or a coordinated beamforming (Co-BF) transmission.

[0308] The first AP can obtain information regarding the Tone Plan, the type of LTF used, and information regarding the RU. As described above, the information regarding the Tone Plan may include the size and location of the RU, control information related to the RU, information regarding the frequency band in which the RU is included, and information regarding the STA transmitting and receiving the RU. The type of LTF may include information regarding 1x / 2x / 4x and information regarding the tone allocation method of the LTF sequence.

[0309] Additionally, the transmitting device may construct / generate a PPDU based on the acquired control information. The step of constructing / generating the PPDU may include the step of constructing / generating each field of the PPDU. That is, step S1601 includes the step of constructing U-SIG and UHR-SIG fields containing control information regarding the Tone Plan. For example, step S1301 may include the step of constructing a field containing control information indicating the bandwidth of the PPDU and / or the step of constructing a field containing control information (e.g., N bitmap) indicating the size / location of the RU and / or the step of constructing a field containing the identifier of the STA receiving the RU (e.g., AID). In the case of a TB PPDU, only some of the information may be included.

[0310] According to an embodiment of the present disclosure, the first PPDU may be configured as shown in the example of FIG. 15.

[0311] The first AP transmits the first PPDU to one or more first STAs (S1602).

[0312] According to an embodiment of the present disclosure, a first AP transmits a first PPDU for cooperative transmission to one or more first STAs connected to the first AP, and a second AP transmits a second PPDU for cooperative transmission to one or more second STAs connected to the second AP. Here, the first AP and the second AP may perform concurrent transmission.

[0313] According to an embodiment of the present disclosure, the first PPDU may include a common preamble with the second PPDU transmitted from the second AP for cooperative transmission to one or more second STAs.

[0314] Here, the common preamble may include information regarding the number of one or more first STAs. For example, the common preamble may include an ultra-high reliability-signal (UHR-SIG) field, and information regarding the number of one or more first STAs may be included in a common field within the UHR-SIG field.

[0315] Additionally, the common preamble may further include information regarding the number of one or more second STAs. Additionally, the common preamble may further include information regarding the number of LTF (long training field) symbols of the first PPDU and / or information regarding the number of LTF symbols of the second PPDU.

[0316] Additionally, the common preamble further includes a plurality of spatial configuration information indicating the number of spatial streams for each of the one or more first STAs and the one or more second STAs, and the plurality of spatial configuration information may each be composed of 2 bits.

[0317] Additionally, the common preamble includes an ultra-high reliability-signal (UHR-SIG) field, and information regarding the number of the one or more first STAs may be included in multiple user fields for each of the one or more first STAs and the one or more second STAs within the UHR-SIG field. Here, the number of spatial streams for each of the one or more first STAs and the one or more second STAs may be indicated regardless of the arrangement order of the multiple user fields.

[0318] Additionally, the plurality of user fields may each include a basic service set (BSS) color indication to indicate whether they are associated with the first AP and the second AP.

[0319] In addition, the common field within the UHR-SIG field may individually include a spatial reuse field for the first AP and the second AP, a guard interval (GI) and LTF size (GI+LTF) field, an extra symbol segment (LDPC) field, a pre-forward error correction (FEC) padding factor field, and a packet extension disambiguity (PE) field.

[0320] Here, the first AP can transmit to one or more first STAs based on the first PPDU configured through step S1601.

[0321] For the S1602 operation, at least one of the following operations may be performed: cyclic shift diversity (CSD), spatial mapping, inverse discrete Fourier transform (IDFT) / inverse fast Fourier transform (IFFT) operation, guard interval (GI) insertion.

[0322] The method described in the example of FIG. 16 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. 16 or the examples described above when executed by one or more processors (102).

[0323] FIG. 17 illustrates an STA operation for a PPDU transmission and reception method for cooperative transmission according to one embodiment of the present disclosure.

[0324] FIG. 17 illustrates the operation of an STA based on the previously proposed methods. The example in FIG. 17 is for convenience of explanation and is not intended to limit the scope of the present disclosure. Some step(s) illustrated in FIG. 17 may be omitted depending on the situation and / or setting.

[0325] In the following description, the first AP may correspond to a coordinating AP, a sharing AP, etc., and the second AP may correspond to a coordinated AP, a shred AP, etc. Or conversely, the first AP may correspond to a coordinated AP, a shred AP, etc., and the second AP may correspond to a coordinating AP, a sharing AP, etc.

[0326] The STA receives a first PPDU for cooperative transmission from the first AP (S1701).

[0327] Here, the cooperative transmission can be a coordinated spatial reused (Co-SR) transmission or a coordinated beamforming (Co-BF) transmission.

[0328] According to an embodiment of the present disclosure, the first PPDU may be configured as shown in the example of FIG. 15.

[0329] Here, the STA can receive all or part of the PPDU through step S1701. Here, for the operation of step S1701, the STA can perform an operation to restore the results of the CSD, Spatial Mapping, IDFT / IFFT, and GI insert operations applied by the AP (e.g., applied in step S1602 above).

[0330] STA processes the first PPDU (S1702).

[0331] Here, the STA can perform decoding on all or part of the PPDU. In addition, the STA can obtain control information related to the Tone Plan (i.e., RU) from the decoded PPDU.

[0332] More specifically, STA can decode the L-SIG and U-SIG fields of PPDU based on Legacy STF / LTF and obtain information contained in the L-SIG and U-SIG fields. For example, information regarding various Tone Plans (i.e., RU) proposed in this disclosure may be included in the UHR-SIG field, and STA can obtain information regarding the Tone Plan (i.e., RU) through the UHR-SIG field.

[0333] In addition, the STA can decode the remaining part of the PPDU based on information regarding the acquired Tone Plan (i.e., RU). For example, the STA can decode the STF / LTF field of the PPDU based on information regarding the tone Plan (i.e., RU). According to an embodiment of the present disclosure, a tone allocation method for the LTF sequence of the LTF field can be determined, and channel estimation can be performed in the LTF field based thereon. Additionally, the receiving device can decode the data field of the PPDU based on information regarding the Tone Plan (i.e., RU) and acquire the MPDU contained in the data field.

[0334] Additionally, the receiving device can perform a processing operation to transmit the decoded data to an upper layer (e.g., the MAC layer). Furthermore, if the generation of a signal is instructed from the upper layer to the PHY layer in response to the data transmitted to the upper layer, a subsequent operation can be performed.

[0335] According to an embodiment of the present disclosure, a first AP transmits a first PPDU for cooperative transmission to one or more first STAs connected to the first AP, and a second AP transmits a second PPDU for cooperative transmission to one or more second STAs connected to the second AP. Here, the first AP and the second AP may perform concurrent transmission.

[0336] According to an embodiment of the present disclosure, the first PPDU may include a common preamble with the second PPDU transmitted from the second AP for cooperative transmission to one or more second STAs.

[0337] Here, the common preamble may include information regarding the number of one or more first STAs. For example, the common preamble may include an ultra-high reliability-signal (UHR-SIG) field, and information regarding the number of one or more first STAs may be included in a common field within the UHR-SIG field.

[0338] Additionally, the common preamble may further include information regarding the number of one or more second STAs. Additionally, the common preamble may further include information regarding the number of LTF (long training field) symbols of the first PPDU and / or information regarding the number of LTF symbols of the second PPDU.

[0339] Additionally, the common preamble further includes a plurality of spatial configuration information indicating the number of spatial streams for each of the one or more first STAs and the one or more second STAs, and the plurality of spatial configuration information may each be composed of 2 bits.

[0340] Additionally, the common preamble includes an ultra-high reliability-signal (UHR-SIG) field, and information regarding the number of the one or more first STAs may be included in multiple user fields for each of the one or more first STAs and the one or more second STAs within the UHR-SIG field. Here, the number of spatial streams for each of the one or more first STAs and the one or more second STAs may be indicated regardless of the arrangement order of the multiple user fields.

[0341] Additionally, the plurality of user fields may each include a basic service set (BSS) color indication to indicate whether they are associated with the first AP and the second AP.

[0342] In addition, the common field within the UHR-SIG field may individually include a spatial reuse field for the first AP and the second AP, a guard interval (GI) and LTF size (GI+LTF) field, an extra symbol segment (LDPC) field, a pre-forward error correction (FEC) padding factor field, and a packet extension disambiguity (PE) field.

[0343] The method described in the example of FIG. 17 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. 17 or the examples described above when executed by one or more processors (202).

[0344] In existing wireless LAN systems, each AP performs transmission to the STA associated with it within its own BSS, but unlike this, according to the examples of the present disclosure, multiple APs can perform cooperative transmission (or concurrent transmission) (e.g., Co-SR transmission or Co-BF transmission), thereby improving throughput and reducing latency, and thus achieving the effect of increasing wireless communication efficiency.

[0345] 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.

[0346] 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.

[0347] 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.

[0348] 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

In a method performed by a first access point (AP) in a wireless LAN system, the method is: A step of generating a first PPDU (physical protocol data unit) for cooperative transmission; and The method includes the step of transmitting the first PPDU to one or more first stations (STA) connected to the first AP, and The first PPDU includes a common preamble with the second PPDU transmitted from the second AP for cooperative transmission to one or more second STAs, and A method in which the above common preamble includes information on the number of the one or more first STAs. In paragraph 1, The above common preamble includes a UHR-SIG (ultra high reliability-signal) field, and A method in which information regarding the number of one or more first STAs is included in a common field within the UHR-SIG field. In paragraph 1, A method in which the above common preamble further includes information regarding the number of the one or more second STAs. In paragraph 1, A method in which the above common preamble further comprises information on the number of LTF (long training field) symbols of the first PPDU and / or information on the number of LTF symbols of the second PPDU. In paragraph 1, The above common preamble further includes a plurality of spatial configuration information indicating the number of spatial streams for each of the one or more first STAs and the one or more second STAs, and A method in which the above plurality of space setting information are each composed of 2 bits. In paragraph 5, The above common preamble includes a UHR-SIG (ultra high reliability-signal) field, and A method in which information regarding the number of the one or more first STAs is included in a plurality of user fields for each of the one or more first STAs and the one or more second STAs within the UHR-SIG field. In paragraph 6, A method in which the number of spatial streams for each of the one or more first STAs and the one or more second STAs is indicated regardless of the arrangement order of the plurality of user fields. In paragraph 6, A method comprising a plurality of user fields each including a basic service set (BSS) color indication for indicating whether they are associated with the first AP and the second AP. In paragraph 2, A method in which the common field within the above UHR-SIG field individually includes a spatial reuse field for the first AP and the second AP, a guard interval (GI) and LTF size (GI+LTF) field, a low-density parity check (LDPC) extra symbol segment field, a pre-forward error correction (FEC) padding factor field, and a packet extension (PE) disambiguity field. In paragraph 1, The above cooperative transmission is a method in which the cooperative transmission is a coordinated spatial reused (Co-SR) transmission or a coordinated beamforming (Co-BF) transmission. The first access point (AP) device is: One or more transceivers; and It includes one or more processors connected to the above one or more transmitters and receivers, and The above one or more processors are: A step of generating a first PPDU (physical protocol data unit) for cooperative transmission; and It is configured to transmit the first PPDU to one or more first stations (STA) connected to the first AP, and The first PPDU includes a common preamble with the second PPDU transmitted from the second AP for cooperative transmission to one or more second STAs, and A method in which the above common preamble includes a field for the number of the one or more first STAs. In a method performed by a first station (STA) in a wireless LAN system, the method is: A step of receiving a first PPDU (physical protocol data unit) for cooperative transmission from a first access point (AP); and The step of processing the first PPDU above is included, The first PPDU includes a common preamble with the second PPDU transmitted from the second AP for cooperative transmission to one or more second STAs, and A method in which the above common preamble includes a field for the number of the one or more first STAs. In a first station (STA) device, the device is: One or more transceivers; and It includes one or more processors connected to the above one or more transmitters and receivers, and The above one or more processors are: Receive a first PPDU (physical protocol data unit) for cooperative transmission from a first access point (AP); and It is configured to process the above-mentioned first PPDU, and The first PPDU includes a common preamble with the second PPDU transmitted from the second AP for cooperative transmission to one or more second STAs, and The above common preamble is a first STA device comprising a field for the number of the one or more first STAs. In a processing device configured to control a station (STA) in a wireless LAN system, the processing device: One or more processors; and A processing device comprising one or more computer memories that are operably connected to one or more processors and store instructions for performing the method according to claim 12 based on execution by one or more processors. One or more non-transitory computer-readable media storing one or more instructions, A computer-readable medium in which one or more of the above commands are executed by one or more processors to control a device in a wireless LAN system to perform the method according to claim 12.

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