Method and device for millimeter wave band-based frame transmission and reception in wireless LAN system

Abstract

Disclosed are a method and device for millimeter wave band-based frame transmission and reception in a wireless LAN system. The method according to one embodiment of the present disclosure may comprise the steps in which: a first station (STA) transmits, to a second station, one or more first frames for beamforming training on the basis of M (M < N) sectors among overall N (N > 1) sectors; and the first STA receives, from the second STA, a second frame including information about the best sector among the M sectors. Here, before the beamforming training, information about the M sectors can be exchanged between the first STA and the second STA.

Description

Method and device for performing frame transmission and reception based on millimeter wave band in a wireless LAN system

[0001] The present disclosure relates to a method and device for transmitting and receiving frames based on a millimeter wave (mmWave) band in a wireless local area network (WLAN) system.

[0002] New technologies have been introduced for wireless local area networks (WLANs) to improve transmission rates, increase bandwidth, enhance reliability, reduce errors, and reduce latency. Among WLAN technologies, the IEEE (Institute of Electrical and Electronics Engineers) 802.11 series of standards can be referred to as Wi-Fi. For example, recently introduced technologies for WLANs 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 a more advanced wireless communication environment, improved technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for Multiple Input Multiple Output (MIMO), which supports increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, and for coordination of multiple access points (APs), are being studied. In particular, various technologies are being studied to support low latency or real-time traffic. Furthermore, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technology.

[0004] The technical problem of the present disclosure is to provide a method and device for transmitting and receiving frames based on a millimeter wave (mmWave) band in a wireless local area network (WLAN) system.

[0005] In particular, the technical task of the present disclosure is to provide a method and device for performing a sector level sweep (SLS) on a millimeter wave (mmWave) band.

[0006] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0007] A method according to one aspect of the present disclosure comprises: a first station (STA) selects M (M) sectors among a total of N (N>1) sectors <N)개의 섹터를 기반으로 하는 빔포밍 훈련을 위한 하나 이상의 제1 프레임을 제2 STA에게 송신하는 단계; 및 상기 제1 STA에 의해서, 상기 M개의 섹터 중 최선의 섹터에 대한 정보를 포함하는 제2 프레임을 상기 제2 STA으로부터 수신하는 단계를 포함할 수 있다. 여기서, 상기 빔포밍 훈련 이전에, 상기 제1 STA와 상기 제2 STA 간에 상기 M개의 섹터에 대한 정보가 교환될 수 있다.

[0008] A method according to an additional aspect of the present disclosure comprises: a second station (STA) for selecting M (M) sectors out of a total of N (N>1) sectors <N)개의 섹터를 기반으로 하는 빔포밍 훈련을 위한 하나 이상의 제1 프레임을 제1 STA로부터 수신하는 단계; 및 상기 제2 STA에 의해서, 상기 M개의 섹터 중 최선의 섹터에 대한 정보를 포함하는 제2 프레임을 상기 제1 STA에게 송신하는 단계를 포함할 수 있다. 여기서, 상기 빔포밍 훈련 이전에, 상기 제1 STA와 상기 제2 STA 간에 상기 M개의 섹터에 대한 정보가 교환될 수 있다.

[0009] According to the present disclosure, a method and device for transmitting and receiving a frame based on a millimeter wave (mmWave) band in a wireless local area network (WLAN) system can be provided.

[0010] According to the present disclosure, a method and device for performing a sector level sweep (SLS) on a millimeter wave (mmWave) band can be provided.

[0011] According to the present disclosure, there is an advantage in that a wireless LAN system can efficiently support the mmWave band, thereby achieving high data rate and low latency.

[0012] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0013] The accompanying drawings, which are incorporated in and are part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and, together with the detailed description, describe the technical features of the present disclosure.

[0014] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0015] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0016] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0017] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0018] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0019] FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0020] FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0021] Figure 8 illustrates a sector level sweep (SLS) step that may be applied to the present disclosure.

[0022] Figure 9 illustrates two types of sector sweeps that may be applied to the present disclosure.

[0023] Figure 10 illustrates a BRP transaction applicable to the present disclosure.

[0024] FIG. 11 is a diagram showing regional examples of channelization of the millimeter wave (mmWave) band to which the present disclosure can be applied.

[0025] FIG. 12 illustrates the operation of a first STA according to an embodiment of the present disclosure.

[0026] FIG. 13 illustrates the operation of a second STA according to an embodiment of the present disclosure.

[0027] FIG. 14 is a diagram for explaining a PPDU transmission and reception procedure between a transmitting STA and a receiving STA according to an embodiment of the present disclosure.

[0028] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, one of ordinary skill in the art will appreciate that the present disclosure may be practiced without these specific details.

[0029] In some cases, to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device.

[0030] In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, the terms "comprises" or "has" in the present disclosure specify the presence of the mentioned features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0031] In this disclosure, terms such as “first,” “second,” etc. are used only to distinguish one component from another and are not used to limit the components, and do not limit the order or importance between the components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0032] The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. The term "and / or" as used herein may refer to any one of the associated enumerated items, or is meant to refer to and encompass any and all possible combinations of two or more of them. Furthermore, the use of " / " between words in this disclosure has the same meaning as "and / or" unless otherwise stated.

[0033] The examples of the present disclosure can be applied to various wireless communication systems. For example, the examples of the present disclosure can be applied to a wireless LAN system. For example, the examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax / be standards. Furthermore, the examples of the present disclosure can be applied to a wireless LAN based on the newly proposed IEEE 802.11bn (or UHR) standard. Additionally, the examples of the present disclosure can be applied to a wireless LAN based on the next-generation standard after IEEE 802.11bn. Furthermore, the examples of the present disclosure can be applied to a cellular wireless communication system. For example, the examples of the present disclosure can be applied to a cellular wireless communication system based on the LTE (Long Term Evolution) series of technologies and the 5G NR (New Radio) series of technologies of the 3rd Generation Partnership Project (3GPP) standard.

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

[0035] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0036] The first device (100) and the second device (200) illustrated in FIG. 1 may be replaced with various terms such as a terminal, a wireless device, a WTRU (Wireless Transmit Receive Unit), a UE (User Equipment), an MS (Mobile Station), a UT (user terminal), an MSS (Mobile Subscriber Station), an MSS (Mobile Subscriber Unit), an SS (Subscriber Station), an AMS (Advanced Mobile Station), a WT (Wireless terminal), or simply a user. In addition, the first device (100) and the second device (200) may be replaced with various terms such as an access point (AP), a BS (Base Station), a fixed station, a Node B, a BTS (Base Transceiver System), a network, an AI (Artificial Intelligence) system, an RSU (road side unit), a repeater, a router, a relay, a gateway, etc.

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

[0038] 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) can include interfaces for a medium access control (MAC) layer and a physical layer (PHY) that follow the provisions of the IEEE 802.11 standard.

[0039] In addition, the first device (100) and the second device (200) may additionally support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) other than wireless LAN technology. In addition, the device of the present disclosure may be implemented as various devices such as a mobile phone, a vehicle, a personal computer, an AR (Augmented Reality) device, a VR (Virtual Reality) device, etc. In addition, the STA of the present specification may support various communication services such as voice calls, video calls, data communications, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).

[0040] A first device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (102) may process information in the memories (104) to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceivers (106). Furthermore, the processor (102) may receive a wireless signal including second information / signals via the transceivers (106), and then store information obtained from signal processing of the second information / signals in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In the present disclosure, a device may also mean a communication modem / circuit / chip.

[0041] The second device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). Furthermore, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement a 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 via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In the present disclosure, a device may also mean a communication modem / circuit / chip.

[0042] Hereinafter, the 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 one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present 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 operational flowcharts disclosed in the present disclosure. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in the present disclosure, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure.

[0043] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a 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 operational 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. The descriptions, functions, procedures, proposals, methods and / or operation flowcharts disclosed in this disclosure may be implemented using firmware or software configured to perform 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 flowcharts disclosed in this disclosure may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0044] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0045] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or flowcharts of the present disclosure, to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts of the present disclosure, from one or more other devices. For example, one or more transceivers (106, 206) can be coupled to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can 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 coupled 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, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure, via one or more antennas (108, 208). In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202).One or more transceivers (106, 206) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0046] 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 transceivers (106, 206) of FIG. 1 may perform transmission and reception operations of signals (e.g., packets or PPDUs (Physical layer Protocol Data Units) according to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). In addition, in the present disclosure, operations in which various STAs generate transmission and reception signals or perform data processing or calculations in advance for transmission and reception signals may be performed in the processors (102, 202) of FIG. 1. For example, an example of an operation for generating a transmission / reception signal or performing data processing or operation in advance for a transmission / reception signal may include 1) an operation for determining / obtaining / configuring / computing / decoding / encoding bit information of a field (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in a PPDU, 2) an operation for determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) used for a field (SIG, STF, LTF, Data, etc.) included in a PPDU, 3) an operation for determining / configuring / obtaining a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an extra sequence applied to SIG) used for a field (SIG, STF, LTF, Data, etc.) included in a PPDU, 4) a power control operation and / or a power saving operation applied to an STA, 5) an operation related to determining / obtaining / configuring / computing / decoding / encoding an ACK signal, etc. Additionally, in the examples below, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / computing / decoding / encoding transmission / reception signals can be stored in the memory (104, 204) of FIG. 1.

[0047] Hereinafter, 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 an AP STA, and the receiver may be part of a non-AP STA. 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 a non-AP STA, and the receiver may be part of an AP STA.

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

[0049] The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports transparent STA mobility to the upper layer can be provided. A Basic Service Set (BSS) corresponds to a basic building block of a wireless LAN. FIG. 2 illustrates, by way of example, 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). The oval representing a BSS in FIG. 2 can also be understood as representing a coverage area in which STAs included in the corresponding BSS maintain communication. This area can be referred to as a Basic Service Area (BSA). When an STA moves outside of a BSA, it cannot directly communicate with other STAs within the BSA.

[0050] If we do not consider the DS illustrated in Figure 2, the most basic type of BSS in a wireless LAN is an Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For example, assuming other components are omitted, BSS1 consisting of only STA1 and STA2, or BSS2 consisting of only STA3 and STA4, can be representative examples of an IBSS, respectively. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, in this type of WLAN, a LAN can be configured when needed rather than being planned in advance, and this can be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and access to distributed systems (DS) is not permitted, forming a self-contained network.

[0051] An STA's membership in a BSS can dynamically change, for example, when an STA is turned on or off, or when an STA enters or leaves a BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services in the BSS infrastructure, an STA must be associated with the BSS. This association can be dynamically established and may involve the use of a Distribution System Service (DSS).

[0052] In a wireless LAN, the direct STA-to-STA distance can be limited by PHY performance. While this distance limit may be sufficient in some cases, communication between STAs over longer distances may be required in other cases. To support extended coverage, a distributed system (DS) can be configured.

[0053] DS refers to a structure in which BSSs are interconnected. Specifically, a BSS may exist as an extended component of a network composed of multiple BSSs, as illustrated in Figure 2. DS is a logical concept and can be specified by the characteristics of a distributed system medium (DSM). In this regard, the Wireless Medium (WM) and DSM can be logically distinguished. Each logical medium is used for a different purpose and by different components. These media are neither limited to being identical nor limited to being different. This logical difference between multiple media explains the flexibility of the WLAN architecture (DS architecture or other network architectures). In other words, the WLAN architecture can be implemented in various ways, and the physical characteristics of each implementation can independently specify the WLAN architecture.

[0054] A DS can support mobile devices by providing seamless integration of multiple BSSs and the logical services necessary to handle addresses to destinations. Additionally, a DS may further include a component called a portal, which acts as a bridge for connecting wireless LANs to other networks (e.g., IEEE 802.X).

[0055] An AP is an entity that enables access to a DS through a WM for associated non-AP STAs and also has the functionality of an STA. Data movement between a BSS and a DS can be performed through an AP. For example, STA2 and STA3 illustrated in FIG. 2 have the functionality of an STA and provide the function of allowing associated non-AP STAs (STA1 and STA4) to access the DS. In addition, since all APs are basically STAs, all APs are addressable entities. The address used by an AP for communication on a WM and the address used by an AP for communication on a DSM do not necessarily have to be the same. A BSS consisting of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0056] Data transmitted from one of the STA(s) associated with an AP to the STA address of that AP may always be received on an uncontrolled port and processed by an IEEE 802.1X port access entity. In addition, if the controlled port is authenticated, the transmitted data (or frame) may be forwarded to the DS.

[0057] In addition to the structure of the DS described above, an extended service set (ESS) may be established to provide wider coverage.

[0058] An ESS is a network of arbitrary size and complexity, consisting of DSs and BSSs. An ESS may correspond to a set of BSSs connected to a DS. However, an ESS does not include a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs within an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs within an ESS may have the same SSID (service set identification). The SSID is distinct from the BSSID, which is the identifier of the BSS.

[0059] In a wireless LAN system, no assumptions are made about the relative physical locations of BSSs, and all of the following configurations are possible: BSSs can be partially overlapping, which is commonly used to provide continuous coverage. BSSs can also be physically disconnected, and there is no logical distance restriction between them. BSSs can also be physically co-located, which can be used to provide redundancy. Furthermore, one (or more) IBSS or ESS networks can physically co-exist with one (or more) ESS networks. This can occur in cases where an ad-hoc network operates at the same location as an ESS network, where physically overlapping wireless networks are configured by different organizations, or where two or more different access and security policies are required at the same location.

[0060] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0061] 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 complete security authentication procedures. The link setup process can also be referred to as the session initiation process or session setup process. Furthermore, the discovery, authentication, association, and security setup processes of the link setup process can be collectively referred to as the association process.

[0062] In step S310, the STA may perform a network discovery operation. This network discovery operation may include scanning operations by the STA. That is, for the STA to access a network, it must search for available networks. Before joining a wireless network, the STA must identify compatible networks. The process of identifying networks in a specific area is called scanning.

[0063] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation including an active scanning process as an example. In active scanning, an STA performing scanning transmits a probe request frame to discover any APs in the vicinity while moving between channels and waits for a response. The responder transmits a probe response frame in response to the STA that transmitted the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In the BSS, the AP transmits the beacon frame, so the AP becomes the responder. In the IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not fixed. 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 (i.e., transmitting and receiving probe requests / responses on channel 2) in the same manner.

[0064] Although not shown in Figure 3, the scanning operation can also be performed in a passive scanning manner. In passive scanning, the STA performing the scanning moves between channels and waits for a beacon frame. A beacon frame is one of the management frames defined in IEEE 802.11. It announces the existence of a wireless network and is periodically transmitted so that the STA performing the scanning can find the wireless network and participate in the wireless network. In the BSS, the AP performs the role of periodically transmitting the beacon frame, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the STA performing the scanning receives a beacon frame, it stores the information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. The STA receiving the beacon frame stores the BSS-related information included in the received beacon frame and moves to the next channel to perform scanning on the next channel in the same manner. Comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0065] 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 of step S340 described below.

[0066] The authentication process involves the STA sending an authentication request frame to the AP, and the AP responding by sending an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0067] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), and a Finite Cyclic Group. These are just some examples of information that may be included in an authentication request / response frame, and may be replaced with other information or include additional information.

[0068] An STA can send an authentication request frame to an AP. The AP can determine whether to grant authentication to the STA based on the information contained in the received authentication request frame. The AP can provide the result of the authentication process to the STA via an authentication response frame.

[0069] After the STA is successfully authenticated, an association process may be performed in step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA.

[0070] For example, the association request frame may include information about various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information about various capabilities, a status code, an Association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. These are just some examples of information that may be included in a combined request / response frame, and may be replaced by other information or include additional information.

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

[0072] The security setup process of step S340 may include, for example, a process of establishing a private key through a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame. Furthermore, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

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

[0074] In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). The CSMA / CA mechanism, also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC, essentially employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA may perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time period (e.g., a DCF Inter-Frame Space (DIFS)) before starting transmission. If the sensing result determines that the medium is in an idle state, the AP and / or STA may start transmitting frames through the 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 may wait for a delay period (e.g., a random backoff period) for medium access before attempting to transmit frames. 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.

[0075] In addition, the IEEE 802.11 MAC protocol provides the Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method that periodically polls all receiving APs and / or STAs to ensure that they receive data frames. In addition, the HCF has the Enhanced Distributed Channel Access (EDCA) and the HCF Controlled Channel Access (HCCA). The EDCA is a contention-based access method for a provider to provide data frames to multiple users, while the HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, the HCF includes a medium access mechanism to improve the Quality of Service (QoS) of the wireless LAN, and can transmit QoS data in both the Contention Period (CP) and the Contention Free Period (CFP).

[0076] Referring to Fig. 4, an operation based on a random backoff period is described. When a medium that was occupied / busy changes to an idle state, multiple STAs can attempt to transmit data (or frames). To minimize collisions, each STA can select a random backoff count, wait for the corresponding slot time, and then attempt transmission. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​in the range of 0 to CW. Here, CW is a contention window parameter value. The CW parameter is given an initial value of CWmin, but can take a value doubled in case of transmission failure (e.g., when an ACK for a transmitted frame is not received). When the CW parameter value becomes CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and if data transmission is successful, it is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are 2. n It is desirable to set it to -1 (n=0, 1, 2, ...).

[0077] Once the random backoff process begins, the STA continues to monitor the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the countdown stops and waits. When the medium becomes idle, the remaining countdown resumes.

[0078] In the example of FIG. 4, when a packet to be transmitted reaches the MAC of STA3, STA3 can immediately transmit a frame if it confirms that the medium is idle for DIFS. The remaining STAs monitor the medium for occupied / busy states and wait. In the meantime, data to be transmitted may also occur in each of STA1, STA2, and STA5, and each STA can count down the backoff slot according to a random backoff count value selected by each STA after waiting for DIFS if the medium is monitored as idle. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. In other words, this example shows a case where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 finishes the backoff count and starts frame transmission. STA1 and STA5 briefly stop counting down and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the backoff count that they had stopped. That is, they can start transmitting frames after counting down the remaining backoff slots equal to the remaining backoff time. Since STA5's remaining backoff time is shorter than STA1's, STA5 starts transmitting frames. While STA2 occupies the medium, STA4 may also have data to transmit. From STA4's perspective, when the medium becomes idle, it waits for DIFS, counts down according to its selected random backoff count value, and then starts transmitting frames. In the example of Figure 4, the remaining backoff time of STA5 coincidentally matches the random backoff count value of STA4, in which case a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 will receive an ACK, resulting in a failure in data transmission.In this case, STA4 and STA5 can select a random backoff count value and perform a countdown after doubling the CW value. STA1 waits while the medium is occupied by transmissions from STA4 and STA5, and when the medium becomes idle, it waits for DIFS and can start transmitting frames after the remaining backoff time elapses.

[0079] As in the example of Fig. 4, a data frame is a frame used for transmitting data forwarded to a higher layer, and can be transmitted after a backoff performed after DIFS elapses from when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff performed after an IFS elapses, such as DIFS or PIFS (Point coordination function IFS). Subtype frames of a management frame include a beacon, an association request / response, a re-association request / response, a probe request / response, and an authentication request / response. A control frame is a frame used to control access to the medium. The subtype frames of the control frame include Request-To-Send (RTS), Clear-To-Send (CTS), Acknowledgment (ACK), Power Save-Poll (PS-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP), and Trigger. If the control frame is not a response frame to the previous frame, it is transmitted after a backoff performed after the DIFS (Direct Inverse Frame Stop) has elapsed, and if it is a response frame to the previous frame, it is transmitted without a backoff performed after the SIFS (short IFS). The type and subtype of the frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0080] A QoS (Quality of Service) STA can transmit a frame after a backoff performed after the AIFS (arbitration IFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), has elapsed. Here, the frames for which AIFS[i] can be used can be data frames, management frames, and also control frames that are not response frames.

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

[0082] As mentioned above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which STAs directly sense the medium. Virtual carrier sensing is intended to address potential issues in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of an STA can utilize a Network Allocation Vector (NAV). The NAV is a value that an STA that is currently using or has the right to use the medium indicates to other STAs the remaining time until the medium becomes available. Therefore, the value set as NAV corresponds to the period during which the STA transmitting the frame is scheduled to use the medium, and an 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 MAC header of the frame.

[0083] In the example of FIG. 5, it is assumed that STA1 wants to transmit data to STA2, and STA3 is in a position to overhear some or all of the frames transmitted and received between STA1 and STA2.

[0084] In order to reduce the possibility of collisions in transmissions of multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, STA3 may determine that the medium is idle based on carrier sensing results. That is, STA1 may correspond to a hidden node for STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, STA3 may determine that the medium is idle based on carrier sensing results. That is, STA2 may correspond to a hidden node for STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, may not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[0085] Specifically, STA1 can determine whether a channel is occupied through carrier sensing. In terms of physical carrier sensing, STA1 can determine channel occupancy idleness based on the energy level or signal correlation detected in the channel. Furthermore, in terms of virtual carrier sensing, STA1 can determine the channel occupancy status using a network allocation vector (NAV) timer.

[0086] STA1 can transmit an RTS frame to STA2 after performing a backoff if the channel is idle during the DIFS. STA2 can transmit a CTS frame, which is a response to the RTS frame, to STA1 after an SIFS if it receives the RTS frame.

[0087] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can use the duration information contained in the RTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can use the duration information contained in the CTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + data frame + SIFS + ACK 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.

[0088] If STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the time when the CTS frame is completely received. If STA2 successfully receives the data frame, it can transmit an ACK frame in response to the data frame to STA1 after SIFS. STA3 can determine whether the channel is in use through carrier sensing if the NAV timer expires. If STA3 determines that the channel is not in use by another terminal during the DIFS after the NAV timer expires, it can attempt channel access after a contention window (CW) based on a random backoff has elapsed.

[0089] FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0090] The PHY layer can prepare an MPDU (MAC PDU) to be transmitted based on an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when a command requesting the start of transmission of the PHY layer is received from the MAC layer, the PHY layer can switch to transmission mode and transmit the information (e.g., data) provided by the MAC layer in the form of a frame. In addition, when the PHY layer detects a valid preamble of the received frame, it monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception of the PHY layer.

[0091] In this way, information transmission / reception in a wireless LAN system is done in the form of frames, and for this purpose, the PHY layer Protocol Data Unit (PPDU) format is defined.

[0092] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a SIGNAL (SIG) field, and a Data field. The most basic (e.g., non-HT (High Throughput) as illustrated in FIG. 7) PPDU format may consist of only the Legacy-STF (L-STF), Legacy-LTF (L-LTF), Legacy-SIG (L-SIG) fields, and a Data field. Additionally, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG field, 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.

[0093] 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, frequency error estimation, etc. STF and LTF can be said to be signals for synchronization and channel estimation of the OFDM physical layer.

[0094] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field may consist of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may include information about the modulation and coding rate of data. For example, the 12-bit Length field may include information about 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 a non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDU, the value of the Length field can be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0095] The data field may include a SERVICE field, a Physical layer Service Data Unit (PSDU), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used to synchronize the descrambler at the receiving end. The PSDU corresponds to a MAC PDU defined at the MAC layer and may contain data generated / used by upper layers. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bit may be used to adjust the length of the data field to a predetermined unit.

[0096] MAC PDUs are 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 MAC PDUs and can be transmitted / received through the PSDU in the data portion of the PPDU format.

[0097] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to a time for transmitting the corresponding frame, etc. The Address subfields may indicate the receiver address, transmitter address, destination address, and source address of the frame, and some Address subfields may be omitted. For specific details of each subfield of the MAC header, including the Sequence Control, QoS Control, and HT Control subfields, refer to the IEEE 802.11 standard document.

[0098] The Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and, if additionally present, non-legacy SIG, non-legacy STF, and non-legacy LTF) in the general PPDU format, and does not include the remaining part (i.e., data field).

[0099] FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0100] Standards such as IEEE 802.11a / g / n / ac / ax use various PPDU formats. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format can also be referred to as the non-HT PPDU format (Fig. 7(a)).

[0101] 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 an HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format that does not include L-STF, L-LTF, and L-SIG, but consists of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTF, and Data fields (not illustrated).

[0102] An example of the VHT PPDU format (IEEE 802.11ac) includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).

[0103] An example of a HE PPDU format (IEEE 802.11ax) additionally includes 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 multi-users (MUs), but the HE-SIG-B is not included in the HE PPDU format for single users (SUs). In addition, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8 microseconds (us). 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 can vary to 16us. For example, the RL-SIG can be configured identically to the L-SIG. The receiving STA can determine that the received PPDU is a HE PPDU or an EHT PPDU, described later, based on the presence of the RL-SIG.

[0104] The EHT PPDU format may include the EHT MU (multi-user) PPDU 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 an RL-SIG following an L-SIG, but may include a U (universal)-SIG, an EHT-SIG, an EHT-STF, and an EHT-LTF following the RL-SIG.

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

[0106] The EHT TB PPDU of Fig. 7(f) omits the EHT-SIG compared to the EHT MU PPDU. An STA that has received 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.

[0107] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated to allow legacy STAs to attempt demodulation and decoding, and mapped based on a predetermined 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 to allow STAs that have successfully decoded non-legacy SIGs (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in the fields, and mapped based on a predetermined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

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

[0109] The U-SIG included in the EHT PPDU format of FIG. 7 can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 us, and the U-SIG can have a total duration of 8 us. 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.

[0110] U-SIGs can be configured in 20MHz units. For example, when an 80MHz PPDU is configured, the same U-SIG can be duplicated in 20MHz units. That is, four identical U-SIGs can be included in an 80MHz PPDU. When the bandwidth exceeds 80MHz, for example, for a 160MHz PPDU, the U-SIGs in the first 80MHz unit and the U-SIGs in the second 80MHz unit can be different.

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

[0112] The A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in a new PPDU format (e.g., UHR PPDU format) not shown in FIG. 7, 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 can be the same, and some or all of the version-dependent bits can be different.

[0113] For example, the size of the version-independent bits of U-SIG can be fixed or variable. The version-independent bits can be assigned only to U-SIG-1 symbols, or to both U-SIG-1 symbols and U-SIG-2 symbols. The version-independent bits and the version-dependent bits can be called by various names, such as the first control bit and the second control bit.

[0114] For example, the version-independent bits of the U-SIG may include a 3-bit PHY version identifier, which may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted and received PPDUs. The version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value of the UL / DL flag field relates to DL communication. The version-independent bits of the U-SIG may include information about the length of a transmission opportunity (TXOP) and information about a BSS color ID.

[0115] For example, the version-dependent bits of the U-SIG may contain information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0116] Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information about bandwidth, information about the MCS technique applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether a dual carrier modulation (DCM) technique (e.g., a technique to achieve an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, information about whether the non-legacy SIG is generated across the entire band, etc.

[0117] Some of the information required for transmitting and receiving a PPDU may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of the non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-legacy LTF and the cyclic prefix (CP) length, information about the guard interval (GI) applicable to the non-legacy LTF, information about preamble puncturing applicable to the PPDU, information about resource unit (RU) allocation, etc. may be included only in the U-SIG, may be included only in the non-legacy SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-legacy SIG.

[0118] Preamble puncturing may refer to the transmission of a PPDU in which no signal is present in one or more frequency units within the PPDU's bandwidth. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth greater than a certain size.

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

[0120] Non-legacy SIGs, such as HE-SIG-B and EHT-SIG, may contain common fields and user-specific fields. Common and user-specific fields may be coded separately.

[0121] In some cases, common fields may be omitted. For example, in a compressed mode where non-OFDMA (orthogonal frequency multiple access) is applied, common fields may be omitted, and multiple STAs may receive PPDUs (e.g., data fields of PPDUs) over the same frequency band. In a non-compressed mode where OFDMA is applied, multiple users may receive PPDUs (e.g., data fields of PPDUs) over different frequency bands.

[0122] 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 can be associated with either MU-MIMO allocation or non-MU-MIMO allocation.

[0123] The common field may include CRC bits and Tail bits, the length of the CRC bits may be determined as 4 bits, and the length of the Tail bits may be determined as 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the location of RUs to which multiple users (i.e., multiple receiving STAs) are allocated.

[0124] An RU can contain multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA techniques. RUs can also be defined when transmitting signals to a single STA. Resources can be allocated on an RU basis for non-legacy STFs, non-legacy LTFs, and data fields.

[0125] Depending on the PPDU bandwidth, an applicable RU size can be defined. The RU 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 80MHz PPDU, the RU arrangements of HE PPDU and EHT PPDU may be different. The applicable RU size, RU number, RU position, DC (direct current) subcarrier position and number, null subcarrier position and number, guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, a tone plan for a wide bandwidth can be defined in the form of multiple repetitions of a low bandwidth tone plan.

[0126] RUs of different sizes can be defined, such as 26-ton RU, 52-ton RU, 106-ton RU, 242-ton RU, 484-ton RU, 996-ton RU, 2X996-ton RU, 4X996-ton RU, etc. A multiple RU (MRU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers consisting 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. Additionally, multiple RUs constituting one MRU may or may not be consecutive in the frequency domain.

[0127] The specific size of an RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in the present disclosure is not limited and is exemplary. Furthermore, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, etc.) in the present disclosure, the number of RUs may vary depending on the RU size.

[0128] The names of each field in the PPDU formats of FIG. 7 are exemplary and the scope of the present disclosure is not limited by those names. Furthermore, the examples of the present disclosure can be applied not only to the PPDU format exemplified in FIG. 7, but also to a new PPDU format in which some fields are excluded and / or some fields are added based on the PPDU formats of FIG. 7.

[0129] beamforming training

[0130] Beamforming training can determine appropriate receive and transmit antenna sectors for paired STAs. This can be achieved by transmitting a bidirectional training frame sequence.

[0131] The beamforming phase is divided into two sub-phases. First, the initial coarse-grain antenna sector configuration can be determined during a sector-level sweep (SLS). This information is used in the subsequent optional beam refinement phase (BRP), where fine-tuning of the selected sectors can be performed.

[0132] First, we describe the operation in the SLS phase.

[0133] During SLS, two STAs can each train a transmit antenna sector or a receive antenna sector.

[0134] During SLS, a pair of stations can exchange a series of Sector Sweep (SSW) frames (or beacons for transmission sector training in PCP / APs) across multiple antenna sectors to determine which sector provides the highest signal quality. For example, during SLS, each station may act as both the transmitter and receiver of the sweep, as illustrated in Figure 8.

[0135] Figure 8 illustrates a sector level sweep (SLS) step that may be applied to the present disclosure.

[0136] Referring to FIG. 8, the STA that performs transmission first may correspond to an initiator, and the other STA that forms a pair may correspond to a responder.

[0137] The initiator's sweep and the responder's sweep can be utilized in two different ways, as shown in Fig. 9.

[0138] Figure 9 illustrates two types of sector sweeps that may be applied to the present disclosure.

[0139] Referring to FIG. 9, (a) of FIG. 9 represents a transmit sector sweep (TXSS), and (b) of FIG. 9 represents a receive sector sweep (RXSS).

[0140] During a Transmit Sector Sweep (TXSS), frames are transmitted from different sectors, while paired nodes can receive in a quasi-omnidirectional pattern. To identify the strongest transmitting sector, the transmitter can mark every frame with an identifier for the antenna and sector used.

[0141] Additionally, during a Receive Sector Sweep (RXSS), transmissions in the same sector (the best known sector) can test the optimal receiving sector at the pairing node. In general, four types of sweep combinations for SLS are possible:

[0142] - Transmit sector sweep (TXSS) on both initiator and responder

[0143] - Receive sector sweep (RXSS) on both STAs

[0144] - Initiator RXSS and responder TXSS

[0145] - Initiator TXSS and responder RXSS

[0146] For the achieved optimal SNR and TXSS, the sector and antenna identifiers can be reported to the pairing node, and such SLS feedback can follow the structure illustrated in FIG. 7.

[0147] Feedback to the initiator is conveyed in every frame of the responder's sector sweep, which can ensure reception under the optimal antenna configuration that is not yet known. Feedback to the responder can be transmitted as a single SSW feedback PPDU / frame using the determined optimal antenna configuration. Finally, the SSW feedback PPDU / frame can be acknowledged by the responder with an SSW-ACK. The final PPDU / frame can be further used to negotiate the details of the subsequent BRP.

[0148] If the two STAs have sufficient transmit antenna gain, their SLS phase can be realized as pure transmit sector training, and the receive sector training can be postponed to a subsequent BRP. In addition, the initiator can instruct / request the responder to perform a receive sector sweep by specifying the number of receive sectors to be trained during its sweep, i.e., the initiator's sweep. If the initiator sweep corresponds to receive sector training, additional signaling may be required before the SLS phase.

[0149] Next, we describe the operation in BRP.

[0150] BRP can refine sectors discovered during the SLS phase. These sectors are determined using a non-uniform quasi-omnidirectional antenna pattern and may have suboptimal signal quality. Furthermore, BRP can predict the optimal antenna weight vector for a phased antenna array, regardless of the predefined sector pattern.

[0151] This allows for an increase in the beam training search space while simultaneously achieving additional throughput gains. While free variation of antenna weight vectors can result in arbitrary antenna patterns, directional characteristics can be preserved for antenna configurations that provide high throughput. Therefore, the training process for predefined directional sectors and antenna weight vector optimization can remain the same. Finally, if BRP is not part of the previous SLS, it can be used to train the receive antenna configuration.

[0152] The BRP transaction can evaluate a set of directional transmit or receive patterns against the best known directional configuration at the pairing node. Therefore, incompleteness of the quasi-omni-directional pattern can be prevented. Since BRP relies on the preceding SLS phase, reliable PPDU / frame exchange is guaranteed and various antenna configurations can be tested within the same PPDU / frame. This can significantly reduce transmission overhead, unlike SLS, which requires an entire PPDU / frame to test a sector. In this regard, transmit and receive training fields (TRN-T / R) can be added to the PPDU / frame exchanged during the BRP transaction to sweep antenna configurations across the entire PPDU / frame. Each field can be transmitted or received with the antenna configuration for which signal quality is being tested. The remainder of the PPDU / frame can be transmitted and received with the best known antenna configuration.

[0153] BRP receive antenna training can be requested by specifying the number of configurations to be tested in the L-RX header field of a PPDU / frame. The pairing node can add that number of TRN-R fields to the next PPDU / frame. Transmit training can be requested by setting the TX-TRN-REQ header field and adding the TRN-T field to the same BRP PPDU / frame. Optionally, an acknowledgement PPDU / frame with the TX-TRN-OK field set and no training fields added can be transmitted by the receiver before the requester adds the TRN-T field to the next PPDU / frame. Similar to SLS, BRP feedback can be provided in the form of the SNR for the best found configuration and, in the case of transmit training, the best configuration ID.

[0154] Figure 10 illustrates a BRP transaction applicable to the present disclosure.

[0155] Referring to FIG. 10, a BRP transaction can be configured to first train the receiving configuration between two STAs and then perform additional transmitting training refinement.

[0156] For example, STA B can combine transmit and receive training requests into a single PPDU / frame using the request variation described above. STA A, on the other hand, can request two transmission directions using two PPDUs / frames.

[0157] The BRP phase may be initiated immediately following the SLS, using an SSW ACK frame for parameter exchange. Alternatively, the BRP phase may be initiated based on a special BRP setup sub-phase consisting of a BRP frame without a training field. In either case, the L-RX and TX-TRN-REQ fields may be used to exchange BRP parameters.

[0158] How to perform beamforming training for specific sectors

[0159] Next-generation wireless LAN systems may utilize the mmWave band, including (for example, not limited to) the 60 GHz band, to improve throughput and efficiency. In this case, beamforming may be essential due to the channel characteristics of the mmWave band.

[0160] However, since the beamforming training procedure for beamforming applications can incur significant overhead, simplification of the beamforming training procedure may be necessary to optimize efficiency. In this regard, performing beam training only on certain sectors may be considered.

[0161] In this disclosure, a method for performing beam training only for a specific sector during beamforming training and a method for transmitting and receiving instruction information for the same are proposed through a detailed description.

[0162] FIG. 11 is a diagram showing regional examples of channelization of the millimeter wave (mmWave) band to which the present disclosure can be applied.

[0163] The example in Figure 11 illustrates the mmWave bands used in the United States, the European Union, South Korea, Japan, Australia, and China, along with the size and location of the channels defined in those bands. For example, each of the six channels may have a bandwidth of 2.16 GHz. Furthermore, when bandwidth bonding is applied, up to four unit bandwidths can be bonded to support a bandwidth of up to 8.64 GHz.

[0164] Unlike conventional wireless LAN systems, technologies currently under discussion, such as UHR, are exploring the use of sub-7 GHz bands (e.g., 2.4 GHz, 5 GHz, or 6 GHz) and / or mmWave bands to achieve high data rates and low latency. For example, for certain use cases requiring high throughput, transmitting / receiving specific PPDUs over mmWave bands may be considered, as currently defined channel bandwidths alone may not meet these requirements.

[0165] In this regard, due to channel characteristics in the mmWave band, beamforming PPDUs must be transmitted. This may necessitate the use of Sector-Level Sweep (SLS) procedures and / or Beam Refinement Protocol (BRP) procedures. However, these procedures can incur significant overhead, and thus, streamlining them may be necessary to optimize efficiency.

[0166] To this end, as a method of performing beam training only for some sectors as described above, a method of directing only a specific portion of sectors during beamforming training is specifically described.

[0167] Control frames or elements for SLS procedures and / or BRP procedures in the mmWave band may be transmitted in the sub-7 GHz band.

[0168] For example, each STA(s) can exchange information about a transmit sector (TX sector) and / or a receive sector (RX sector) used for beam training in an SLS procedure and / or a BRP procedure, etc., using the corresponding control frame or element. At this time, individual frames or elements can be defined for each of the SLS procedure and / or the BRP procedure, or the same frame or element can be used. When the same frame or element is used, necessary information can be transmitted by distinguishing between the SLS procedure and / or the BRP procedure, or the same information can be transmitted without distinguishing between them. As another example, before performing the SLS procedure and / or the BRP procedure, a frame for initiating the SLS procedure and / or the BRP procedure can be transmitted in the sub-7 GHz band. Each STA(s) can exchange information about a transmit sector and / or a receive sector used for beam training in an SLS procedure and / or the BRP procedure, etc., through the corresponding frame.

[0169] Additionally, the location of each STA(s) can be roughly identified through transmission and reception of specific frames and / or PPDUs in the sub-7 GHz band. Based on this, only some sectors, rather than all, may be considered during beamforming training with a specific STA. In this case, a signaling method for indicating these specific sectors needs to be defined.

[0170] The signaling may be additionally included in a control frame or element for the aforementioned SLS procedure and / or BRP procedure, or may be additionally included in a frame for the SLS procedure and / or BRP procedure. Various methods for the signaling are described below through embodiments.

[0171] Example 1

[0172] An STA transmitting a frame or element for an SLS procedure and / or a BRP procedure (or a frame for initiating an SLS procedure and / or a BRP procedure) may indicate the total number of transmit / receive sectors and the number of partial transmit / receive sectors in the frame or element. Here, the partial number of transmit / receive sectors may correspond to the number of shortlisted transmit / receive sectors for performing beam training for some sectors. In this case, a specific subfield may be defined for the indication, and a specific value may be defined using a certain bit to indicate a specific number.

[0173] Also, in this regard, information about the lowest (or highest) sector ID (identifier) ​​of the corresponding some transmit / receive sectors may be indicated. Based on the indication, a specific subfield may be defined, and a specific value may be defined using a certain bit to indicate a specific sector ID. Based on this, it may be indicated that sector ID(s) corresponding to the number of some transmit / receive sectors in order based on the sector ID will perform transmit / receive beamforming training in the SLS procedure and / or the BRP procedure. For example, consecutive sector IDs may be selected based on the indicated sector ID. When the lowest sector ID is indicated, the sector ID(s) may be selected in order in the indicated number in an increasing order, and when the highest sector ID is indicated, the sector ID(s) may be selected in order in the indicated number in a decreasing order.

[0174] In relation to the method, different subfields for the corresponding instructions may be defined for the transmitting sector and the receiving sector, or if both the transmitting sector and the receiving sector are the same, the instructions may be performed through a single subfield.

[0175] The method may be efficient in terms of reducing the overhead of the SLS procedure and / or the BRP procedure.

[0176] Additionally or alternatively, instructions for certain sectors may be performed based on a bitmap. That is, the ID(s) of specific sector(s) selected for efficient beamforming training may be indicated in a bitmap manner. For example, each bit of the bitmap may be sequentially mapped to a low sector ID or a high sector ID, and a 0 or 1 may indicate whether the sector(s) are selected for beamforming training. This may increase overhead when the number of sectors increases, but it has the technical effect of allowing the selection of non-contiguous sector IDs. In this regard, different subfields for the instructions may be defined for each transmitting and receiving sector, or, if both the transmitting and receiving sectors are the same, the instructions may be performed through a single subfield.

[0177] Example 2

[0178] An STA transmitting a frame or element for an SLS procedure and / or a BRP procedure (or a frame for initiating an SLS procedure and / or a BRP procedure) may reset the IDs of some transmit / receive sectors in the frame or element, where the number of some transmit / receive sectors may correspond to the number of shortlisted transmit / receive sectors for performing beam training on some sectors.

[0179] For example, rather than using the existing sector IDs, sector IDs can be reallocated in descending order of the lowest or highest sector ID among the selected sectors (e.g., selected for beamforming training on some sectors). In this case, sector IDs with a value of 0 can be allocated first.

[0180] Based on this, some of the transmit / receive sector counts may be indicated without indicating the total transmit / receive sector count, and additional instructions may be unnecessary.

[0181] In relation to the method, different subfields for the corresponding instructions may be defined for the transmitting sector and the receiving sector, or if both the transmitting sector and the receiving sector are the same, the instructions may be performed through a single subfield.

[0182] This method has a technical effect of reducing overhead compared to the aforementioned methods (e.g., embodiment 1).

[0183] In connection with embodiments of the present disclosure, when transmitting a PPDU for an SLS procedure and / or a BRP procedure in an (actual) mmWave band, information regarding a sector ID (e.g., a transmission sector ID) in which the PPDU is transmitted may be included. For example, the information may be transmittable in a physical signaling (PHY signaling) field within the PPDU or a MAC frame. A receiving side (e.g., an STA that has received the PPDU) may feed back information regarding an optimal transmission sector ID (to the transmitting side) based on information received in the sub-7 GHz band. Additionally, when providing feedback, the receiving side may transmit the feedback by including a field (e.g., a training (TRN) field) for receiving beamforming training of the STA receiving the feedback. In this case, the field may be configured using sector information used in receiving beamforming training received in the sub-7 GHz band.

[0184] In addition, in relation to embodiments of the present disclosure, unlike the method of indicating information about some of the transmitting / receiving sectors of an STA that transmits a frame or element for an SLS procedure and / or a BRP procedure (or a frame for initiating an SLS procedure and / or a BRP procedure), a method of indicating information about some of the transmitting / receiving sectors of an STA that receives the frame or element may also be considered. Here, the number of some of the transmitting / receiving sectors may correspond to the number of shortlisted transmitting / receiving sectors for performing beam training for some of the sectors. In this case, the indication may be performed in a manner identical to / similar to the method described above in the present disclosure. However, information about all of the sectors of the receiving STA may be required before transmitting the frame or element, and the information may be exchanged / obtained through capability negotiation, etc. Additionally, based on the information, when transmitting a PPDU for an SLS procedure and / or a BRP procedure in the (actual) mmWave band, a field (e.g., a training (TRN) field) for training the reception beamforming of an STA receiving the PPDU may be inserted. In this case, the field may be configured using sector information used in the reception beamforming training.

[0185] Additionally, in connection with embodiments of the present disclosure, when scheduling an SLS procedure and / or a BRP procedure, procedures for all transmit / receive sectors may be scheduled on specific time / frequency resources, and procedures for some transmit / receive sectors may be scheduled on other time / frequency resources. In this regard, information (e.g., 1-bit information) for indicating a procedure for all transmit / receive sectors or a procedure for some transmit / receive sectors may be additionally transmitted / received / exchanged between STAs. For example, the information may be conveyed in a frame for initiating an SLS procedure and / or a BRP procedure.

[0186] Hereinafter, the operation of the STA according to the embodiment of the present disclosure described above will be described with reference to FIGS. 12 and 13. That is, the examples of FIGS. 12 and 13 may correspond to some of the various examples of the present disclosure.

[0187] FIG. 12 illustrates the operation of a first STA according to an embodiment of the present disclosure.

[0188] Referring to Figure 12, the first STA selects M (M) sectors from among the total N (N>1) sectors. <N)개의 섹터를 기반으로 하는 빔포밍 훈련을 위한 하나 이상의 제1 프레임을 제2 STA에게 송신할 수 있다(S1210). 즉, 제1 STA와 제2 STA 간에, 전체 섹터 중 일부 섹터만을 기반으로 하는 빔포밍 훈련이 수행될 수 있다.

[0189] For example, beamforming training may include one or more of a first procedure for a sector-level sweep or a second procedure for a beam refinement protocol. Furthermore, for example, for the beamforming training, the first STA may correspond to an initiator, and the second STA may correspond to a responder. Furthermore, for example, the first frame may be for beamforming training for the transmission sector of the first STA.

[0190] Thereafter, the first STA can receive a second frame (e.g., a feedback frame) containing information about the best sector among the aforementioned M sectors from the second STA (S1220).

[0191] In this regard, prior to the beamforming training, information about some sectors, i.e., the M sectors described above, may be exchanged between the first STA and the second STA.

[0192] According to the present disclosure, information about M sectors may include at least one of the number of sectors (e.g., M) or a specific sector ID. Here, the specific sector ID may correspond to the highest sector ID or the lowest sector ID among the M sectors. For example, if the number of sectors and the highest sector ID are included in the information about M sectors, the M sectors may correspond to sectors having IDs in descending order based on the highest sector ID. Conversely, if the number of sectors and the lowest sector ID are included in the information about M sectors, the M sectors may correspond to sectors having IDs in ascending order based on the lowest sector ID.

[0193] Additionally, according to the present disclosure, information about the M sectors may be based on a bitmap scheme in which each bit is mapped to a sector ID. For example, a scheme may be applied in which M bits in a bitmap consisting of N bits based on a total of N sectors are set to specific values ​​(e.g., 0 or 1) to indicate some of the M sectors.

[0194] Additionally, according to the present disclosure, when the transmitting sector and the receiving sector are different from each other, the information about the aforementioned M sectors can be individually set for the transmitting sector and the receiving sector (e.g., through separate (sub)fields). On the other hand, when the transmitting sector and the receiving sector are the same, the information about the aforementioned M sectors can be set for the transmitting sector and the receiving sector through a single (sub)field.

[0195] Additionally, according to the present disclosure, information about the aforementioned M sectors may be included in a control frame for beamforming training or may be included in a frame for initiating the beamforming training.

[0196] Additionally, according to the present disclosure, information about the aforementioned M sectors may be exchanged in a first operating frequency band, and beamforming training may be performed in a second operating frequency band different from the first operating frequency band. For example, the first operating frequency band may correspond to one of the 2.4 GHz band, the 5 GHz band, or the 6 GHz band (e.g., a sub-7 GHz band), and the second operating frequency band may correspond to the millimeter wave (mmWave) band or the 60 GHz band.

[0197] Additionally, according to the present disclosure, the second frame transmitted by the second STA may further include a training field for receiving beamforming training by the first STA.

[0198] Additionally, according to the present disclosure, a first beamforming training type based on all N sectors in a specific time resource or a specific frequency resource may be scheduled, and a second beamforming training type based on some M sectors in another time resource or another frequency resource may be scheduled. In this regard, information indicating a beamforming training type (e.g., one of the first beamforming training type or the second beamforming training type) may be included in a frame for initiating beamforming training.

[0199] The method performed by the first STA described in the example of FIG. 12 may 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 transmit, through one or more transceivers (106), one or more first frames for beamforming training based on some M sectors out of the total N sectors, and receive a second frame including information about a best sector out of the M sectors. Furthermore, one or more memories (104) of the first device (100) may store commands for performing the method described in the example of FIG. 12 or the examples described above when executed by one or more processors (102).

[0200] FIG. 13 illustrates the operation of a second STA according to an embodiment of the present disclosure.

[0201] Referring to Figure 13, the second STA is M (M) out of the total N (N>1) sectors. <N)개의 섹터를 기반으로 하는 빔포밍 훈련을 위한 하나 이상의 제1 프레임을 제1 STA으로부터 수신할 수 있다(S1310). 즉, 제1 STA와 제2 STA 간에, 전체 섹터 중 일부 섹터만을 기반으로 하는 빔포밍 훈련이 수행될 수 있다.

[0202] For example, beamforming training may include one or more of a first procedure for a sector-level sweep or a second procedure for a beam refinement protocol. Furthermore, for example, for the beamforming training, the first STA may correspond to an initiator, and the second STA may correspond to a responder. Furthermore, for example, the first frame may be for beamforming training for the transmission sector of the first STA.

[0203] Thereafter, the second STA can transmit a second frame (e.g., a feedback frame) containing information about the best sector among the aforementioned M sectors to the first STA (S1320).

[0204] In this regard, prior to the beamforming training, information about some sectors, i.e., the M sectors described above, may be exchanged between the first STA and the second STA.

[0205] In the example of Fig. 13, the specific details of the configuration of information for M sectors, transmission method, operating frequency band, training field, beamforming training scheduling, etc. are the same as those described in the example of Fig. 12, so redundant descriptions are omitted.

[0206] The method performed by the second STA described in the example of FIG. 13 may 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 one or more first frames for beamforming training based on M sectors out of a total of N sectors through one or more transceivers (206), and to transmit a second frame including information about a best sector out of the M sectors. Furthermore, one or more memories (204) of the second device (200) may store commands for performing the method described in the example of FIG. 13 or the examples described above when executed by one or more processors (202).

[0207] FIG. 14 is a diagram for explaining a PPDU transmission and reception procedure between a transmitting STA and a receiving STA according to an embodiment of the present disclosure.

[0208] For example, with respect to the procedure in FIG. 14, a PPDU that can be used in the mmWave band of a UHR system may include UHR-STF, UHR-LTF, UHR-SIG, and data. All or part of each part (e.g., field) may be divided into one or more subparts (e.g., subfields).

[0209] In this regard, each field (and its subfields) can be transmitted in units of 4 / N us * M (where N is an upclocking factor and M is an integer). UHR-STF can be transmitted in integer multiples of 0.8 / N us. For example, UHR-STF can be transmitted in 0.8 / N us * 10. In addition, it can include the Guard Interval / N (or Short GI / N) of the conventional wireless LAN system (e.g., WiFi) standard. A common subcarrier frequency spacing value (e.g., delta_f=312.5 kHz* N / M, N=integer) can be applied to all of the fields.

[0210] Additionally, some of the UHR-STF, UHR-LTF, UHR-SIG, and data may be omitted. For example, in a PPDU for a specific purpose (e.g., SLS), data or UHR-SIG may not be present. For another example, a training field (e.g., a training field) may be present at the end of a PPDU for a specific purpose.

[0211] For example, UHR-STF may be configured as L-STF or VHT-STF or HE-STF or EHT-STF according to the conventional method, and may include fields for CFO estimation and AGC. In addition, UHR-LTF may be configured as L-LTF or VHT-LTF or HE-LTF or EHT-LTF according to the conventional method, and may include fields for CFO estimation and channel estimation. In addition, UHR SIG may include various control information for the transmitted PPDU. For example, it may include control information for decoding data, control information for SLS, etc. In addition, data may include user data and packets for upper layers. That is, it may include MPDUs (e.g., MAC frames). In particular, in the case of a PPDU for SLS, the data may include information for SLS.

[0212] Some of the procedures described below in Fig. 14 may be omitted or changed.

[0213] The transmitting STA can obtain control information for transmitting a PPDU (S1410). For example, the transmitting STA can obtain channel information and bandwidth information for the mmWave band where the PPDU will be transmitted. Furthermore, for PPDU transmission for SLS, the transmitting STA can obtain information about each sector. In this regard, information about only some sectors, not all sectors, may be indicated.

[0214] The transmitting STA may configure / generate a PPDU based on the acquired control information (S1420). The step of configuring / generating the PPDU may include a step of configuring / generating each field of the PPDU. For example, the step of configuring / generating the PPDU may include a step of configuring UHR-STF / UHR-LTF applicable to the bandwidth. In addition, the step of configuring / generating the PPDU may include a step of configuring a UHR-SIG field including information such as the bandwidth. In addition, when transmitting a PPDU for SLS / BRP, the step of configuring / generating the PPDU may include a step of configuring a UHR-SIG field including control information regarding SLS / BRP. In addition, the step of configuring / generating the PPDU may include a step of generating a data field (e.g., MPDU) transmitted in the bandwidth. In addition, the step of configuring / generating the PPDU may include a step of generating a Data part (e.g., MPDU) including information regarding SLS / BRP when transmitting a PPDU for SLS / BRP.

[0215] A transmitting STA may transmit a PPDU configured as described above to a receiving STA. During the PPDU transmission process, the transmitting STA may perform at least one of the following operations: upclocking, CSD, spatial mapping, IDFT / IFFT operation, and GI insertion.

[0216] The receiving STA may receive all or part of the PPDU (S1440). For example, the receiving STA may perform operations to restore the results of operations such as upclocking, CSD, spatial mapping, IDFT / IFFT operations, and GI insertion applied during the transmission of the PPDU.

[0217] A receiving STA can decode all or part of a PPDU and obtain control information (e.g., information about bandwidth, etc.) from the decoded PPDU (S1450). For example, the receiving STA can decode the UHR-SIG of the PPDU based on the UHR-STF / UHR-LTF and obtain information included in the UHR-SIG field. Various information described in the present disclosure can be included in the UHR-SIG, and the receiving STA can obtain information about the PPDU through the UHR-SIG. In particular, when receiving a PPDU for SLS, the receiving STA can obtain control information about SLS, etc. through the PPDU.

[0218] The receiving STA can decode the data field of the PPDU based on the information acquired as described above and acquire the MPDU included in the data field (S1460). In addition, the receiving STA can perform a processing operation to transmit the decoded data to a higher layer (e.g., MAC layer). In addition, if the upper layer instructs the PHY layer to generate a signal in response to the data transmitted to the upper layer, the receiving STA can perform a subsequent operation.

[0219] The proposed method in this disclosure relates to a method for performing beamforming training for selected sectors in the mmWave band. The proposed method in this disclosure achieves novel effects, such as improving throughput and / or efficiency in newly defined operating bands (e.g., mmWave bands), and reducing overhead by performing beamforming training only for selected sectors.

[0220] The embodiments described above are combinations of components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form 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 self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form embodiments or incorporated as new claims through post-application amendments.

[0221] It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential characteristics thereof. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present disclosure are intended to be included within the scope of the present disclosure.

[0222] The scope of the present disclosure includes software or machine-executable instructions (e.g., an operating system, an application, firmware, a program, etc.) that cause operations according to the methods of various embodiments to be executed on a device or a computer, and a non-transitory computer-readable medium having such software or instructions stored thereon and executable on the device or computer. Instructions that can be used to program a processing system to perform the features described in the present disclosure can be stored on / in a storage medium or a computer-readable storage medium, and a computer program product including such a storage medium can be used to implement the features described in the present disclosure. The storage medium can include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices, and can include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory optionally includes one or more storage devices remotely located from the processor(s). The memory or, alternatively, the non-volatile memory device(s) within the memory comprise a non-transitory computer-readable storage medium. The features described in this disclosure may be incorporated into software and / or firmware stored on any of the machine-readable media, which may control the hardware of the processing system and allow the processing system to interact with other mechanisms that utilize results according to embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0223] The method proposed in this disclosure has been described with a focus on examples applied to IEEE 802.11-based systems, but can be applied to various wireless LANs or wireless communication systems in addition to IEEE 802.11-based systems.

Claims

1. By the first station (STA), M (M) out of the total N (N>1) sectors <N)개의 섹터를 기반으로 하는 빔포밍 훈련을 위한 하나 이상의 제1 프레임을 제2 STA에게 송신하는 단계; 및 A step of receiving, by the first STA, a second frame including information about a best sector among the M sectors from the second STA, A method in which information about the M sectors is exchanged between the first STA and the second STA prior to the beamforming training.

2. In paragraph 1, The information about the above M sectors includes at least one of the number of sectors or a specific sector ID, A method wherein the specific sector ID corresponds to the highest sector ID or the lowest sector ID among the M sectors.

3. In paragraph 2, A method wherein, based on the number of sectors and the highest sector ID being included in the information about the M sectors, the M sectors correspond to sectors having IDs in descending order based on the highest sector ID.

4. In paragraph 2, A method wherein, based on the number of sectors and the lowest sector ID being included in the information about the M sectors, the M sectors correspond to sectors having IDs in ascending order based on the lowest sector ID.

5. In paragraph 1, A method in which information about the above M sectors is based on a bitmap method in which each bit is mapped to a sector ID.

6. In paragraph 1, A method wherein information about the M sectors is individually set for the transmitting sector and the receiving sector based on differences between the transmitting sector and the receiving sector.

7. In paragraph 1, A method wherein information about the M sectors is included in a control frame for the beamforming training or included in a frame for initiating the beamforming training.

8. In paragraph 1, Information about the above M sectors is exchanged in the first operating frequency band, A method wherein the beamforming training is performed in a second operating frequency band different from the first operating frequency band.

9. In paragraph 8, The above first operating frequency band corresponds to one of the 2.4 GHz band, the 5 GHz band, or the 6 GHz band, The above second operating frequency band corresponds to a millimeter wave (mmWave) band or a 60 GHz band.

10. In paragraph 1, A method, wherein the second frame further includes a training field for receiving beamforming training by the first STA.

11. In paragraph 1, A method wherein the beamforming training comprises at least one of a first procedure for a sector level sweep or a second procedure for a beam refinement protocol.

12. In paragraph 1, A first beamforming training type based on the above N sectors in a specific time resource or a specific frequency resource is scheduled, A method wherein a second beamforming training type based on the M sectors is scheduled on different time resources or different frequency resources.

13. In paragraph 12, A method wherein information indicating one of the first beamforming training type or the second beamforming training type is included in a frame for initiating beamforming training.

14. One or more transmitters / receivers; and comprising one or more processors coupled to said one or more transceivers; One or more of the above processors: By the first station (STA), M (M) out of the total N (N>1) sectors <N)개의 섹터를 기반으로 하는 빔포밍 훈련을 위한 하나 이상의 제1 프레임을 제2 STA에게 송신하고; By the first STA, a second frame including information about the best sector among the M sectors is set to be received from the second STA, A device in which information about the M sectors is exchanged between the first STA and the second STA prior to the beamforming training.

15. By the second station (STA), M (M) out of the total N (N>1) sectors <N)개의 섹터를 기반으로 하는 빔포밍 훈련을 위한 하나 이상의 제1 프레임을 제1 STA로부터 수신하는 단계; 및 A step of transmitting, by the second STA, a second frame including information about the best sector among the M sectors to the first STA, A method in which information about the M sectors is exchanged between the first STA and the second STA prior to the beamforming training.

16. One or more transmitters / receivers; and comprising one or more processors coupled to said one or more transceivers; One or more of the above processors: By the second station (STA), M (M) out of the total N (N>1) sectors <N)개의 섹터를 기반으로 하는 빔포밍 훈련을 위한 하나 이상의 제1 프레임을 제1 STA로부터 수신하고; By the second STA, a second frame including information about the best sector among the M sectors is set to be transmitted to the first STA, A device in which information about the M sectors is exchanged between the first STA and the second STA prior to the beamforming training.

17. One or more processors; and A processing device comprising one or more computer memories operatively connected to said one or more processors and storing instructions for performing a method according to any one of claims 1 to 13 based on execution by said one or more processors.

18. One or more non-transitory computer-readable media storing one or more instructions that are executed by one or more processors to perform a method according to any one of claims 1 to 13.

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