WO2017022922A1 - Appareil et procédé d'émission-réception dans un système de communications sans fil - Google Patents

Appareil et procédé d'émission-réception dans un système de communications sans fil Download PDF

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Publication number
WO2017022922A1
WO2017022922A1 PCT/KR2016/002806 KR2016002806W WO2017022922A1 WO 2017022922 A1 WO2017022922 A1 WO 2017022922A1 KR 2016002806 W KR2016002806 W KR 2016002806W WO 2017022922 A1 WO2017022922 A1 WO 2017022922A1
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sequence
tone
stf
tones
mhz
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PCT/KR2016/002806
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English (en)
Korean (ko)
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박은성
최진수
조한규
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엘지전자(주)
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path

Definitions

  • the present invention relates to a wireless communication system, and more particularly, proposes an efficient HE-STF sequence that can be applied to a new frame and numerology of a next-generation WirelessLAN system and can minimize PAPR.
  • Wi-Fi is a Wireless Local Area Network (WLAN) technology that allows devices to access the Internet in the 2.4 GHz, 5 GHz, or 6 GHz frequency bands.
  • WLAN Wireless Local Area Network
  • WLANs are based on the Institute of Electrical and Electronic Engineers (IEEE) 802.11 standard.
  • IEEE 802.11 The Wireless Next Generation Standing Committee (WNG SC) of IEEE 802.11 is an ad hoc committee that considers the next generation wireless local area network (WLAN) in the medium to long term.
  • WNG SC Wireless Next Generation Standing Committee
  • IEEE 802.11n aims to increase the speed and reliability of networks and to extend the operating range of wireless networks. More specifically, IEEE 802.11n supports High Throughput (HT), which provides up to 600 Mbps data rate, and also supports both transmitter and receiver to minimize transmission errors and optimize data rates. It is based on Multiple Inputs and Multiple Outputs (MIMO) technology using multiple antennas.
  • HT High Throughput
  • MIMO Multiple Inputs and Multiple Outputs
  • IEEE 802.11ac supports data processing speeds of 1 Gbps and higher via 80 MHz bandwidth transmission and / or higher bandwidth transmission (eg 160 MHz) and operates primarily in the 5 GHz band.
  • IEEE 802.11ax often discussed in the next-generation WLAN study group called IEEE 802.11ax or High Efficiency (HEW) WLAN, is: 1) 802.11 physical layer and MAC in the 2.4 GHz and 5 GHz bands. (medium access control) layer enhancement, 2) spectral efficiency and area throughput improvement, 3) environments with interference sources, dense heterogeneous network environments, and high user loads. Such as improving performance in real indoor environments and outdoor environments, such as the environment.
  • IEEE 802.11ax High Efficiency
  • IEEE 802.11ax Scenarios considered mainly in IEEE 802.11ax are dense environments with many access points (APs) and stations (STAs), and IEEE 802.11ax discusses spectral efficiency and area throughput improvement in such a situation. . In particular, there is an interest in improving the performance of the indoor environment as well as the outdoor environment, which is not much considered in the existing WLAN.
  • IEEE 802.11ax we are interested in scenarios such as wireless office, smart home, stadium, hotspot, and building / apartment. There is a discussion about improving system performance in dense environments with many STAs.
  • IEEE 802.11ax improves system performance in outdoor basic service set (OBSS) environment, outdoor environment performance, and cellular offloading rather than single link performance in one basic service set (BSS). Discussion is expected to be active.
  • the directionality of IEEE 802.11ax means that next-generation WLANs will increasingly have a technology range similar to that of mobile communication. Considering the situation where mobile communication and WLAN technology are recently discussed in the small cell and direct-to-direct communication area, the technical and business of next-generation WLAN and mobile communication based on IEEE 802.11ax Convergence is expected to become more active.
  • the present invention proposes an efficient (1x, 2x) HE-STF sequence suitable for the numerology of the 802.11ax system and minimizing PAPR.
  • an STA apparatus of a WLAN system and a PPDU transmission method of a STA apparatus according to an embodiment of the present invention are proposed.
  • a method of transmitting a physical protocol data unit (PPDU) of a station (STA) device in a wireless LAN (WLAN) system generating a high efficiency-short training field (HE-STF) sequence step; Generating a PPDU including a HE-STF field configured based on the HE-STF sequence; And transmitting the PPDU, wherein the HE-STF field included in the PPDU is transmitted through a channel.
  • the HE-STF sequence is ⁇ -1, -1, -1, 1, 1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, -1, 1 ⁇ * ( It can be configured based on the M sequence consisting of ⁇ 1/2) (1 + j).
  • the HE-STF field may have a period of 0.8 ms.
  • the HE-STF sequence is composed of the M sequence and 0, and the tone having the tone index 112 to the tone having a tone index -112 among the tones included in the 20 MHz channel. Up to 16 tons can be sequentially mapped.
  • the M sequence may be sequentially mapped in the unit of 16 tones from the tone having the tone index -112 to the tone having the tone index 112, and the 0 may be mapped to the tone having the tone index 0.
  • the HE-STF sequence is composed of ⁇ the M sequence, 0, the M sequence ⁇ , each of the predefined one of 1, -1, j and j for each M sequence Can be multiplied by
  • the HE-STF sequence may be sequentially mapped in units of 16 tones from tones having a tone index of -240 to tones having the tone index 240 among tones included in the 40 MHz channel.
  • the HE-STF sequence is composed of ⁇ the M sequence, a, the M sequence, 0, the M sequence, b, the M sequence ⁇ , each 1, A value of any one of -1, j and j is multiplied, and a and b are ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ Any one of predefined values of 1/2) (-1 + j) and ( ⁇ 1 / 2) (-1-j) may be assigned.
  • the HE-STF sequence may be sequentially mapped in units of 16 tones from tones having a tone index of -496 to tones having a tone index of 496 among tones included in the 80 MHz channel.
  • the HE-STF field may have a 1.6 ms period.
  • the HE-STF sequence is composed of ⁇ the M sequence, 0, the M sequence ⁇ , any one of 1, -1, j and j for each M sequence Can be multiplied by
  • the HE-STF sequence may be sequentially mapped in units of 8 tones from tones having a tone index of -120 to tones having the tone index 120 among tones included in the 20 MHz channel.
  • the HE-STF sequence is composed of ⁇ the M sequence, a, the M sequence, 0, the M sequence, b, the M sequence ⁇ , 1, 1 for each M sequence, A value of any one of -1, j and j is multiplied, and a and b are ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ Any one of predefined values of 1/2) (-1 + j) and ( ⁇ 1 / 2) (-1-j) may be assigned.
  • the HE-STF sequence is sequentially mapped in units of 8 tones from tones having a tone index -248 among the tones included in the 40 MHz channel to tones having the tone index 248, and having the tone indexes -248 and 248. Zero values may be mapped to the tones, respectively.
  • the HE-STF sequence is ⁇ the M sequence, a, the M sequence, b, the M sequence, c, the M sequence, 0, the M sequence, d, the M sequence , e, the M sequence, f, and the M sequence ⁇ , and each of the M sequences is multiplied by a predefined value of 1, -1, j, and j, and a to f are each ( ⁇ ). 1/2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1 + j) and ( ⁇ 1 / 2) (-1-j) values in advance Any defined value can be assigned.
  • the HE-STF sequence is sequentially mapped in units of 8 tones from tones having a tone index -504 among the tones included in the 80 MHz channel to tones having the tone index 504, and having the tone indexes -504 and 504. Zero values may be mapped to the tones, respectively.
  • STA Statation device in a wireless LAN (WLAN) system
  • RF Radio Frequency
  • the processor may include generating a High Efficiency-Short Training Field (HE-STF) sequence, generating a PPDU including an HE-STF field configured based on the HE-STF sequence, and transmitting the PPDU.
  • HE-STF High Efficiency-Short Training Field
  • the HE-STF field included in the PPDU is transmitted through a channel, and the HE-STF sequence is ⁇ -1, -1, -1, 1, 1, 1, -1, 1, 1, 1, It can be configured based on the M sequence consisting of -1, 1, 1, -1, 1 ⁇ * ( ⁇ 1 / 2) (1 + j).
  • the present invention aims to propose an efficient (2x) HE-STF sequence that is suitable for the neurology of 802.11ax system and can minimize the PAPR.
  • FIG. 1 is a diagram illustrating an example of an IEEE 802.11 system to which the present invention can be applied.
  • FIG. 2 is a diagram illustrating a structure of a layer architecture of an IEEE 802.11 system to which the present invention may be applied.
  • FIG. 3 illustrates a non-HT format PPDU and a HT format PPDU of a wireless communication system to which the present invention can be applied.
  • FIG. 4 illustrates a VHT format PPDU format of a wireless communication system to which the present invention can be applied.
  • FIG. 5 is a diagram illustrating a constellation for distinguishing a format of a PPDU of a wireless communication system to which the present invention can be applied.
  • FIG. 6 illustrates a MAC frame format of an IEEE 802.11 system to which the present invention can be applied.
  • FIG. 7 is a diagram illustrating a Frame Control field in a MAC frame in a wireless communication system to which the present invention can be applied.
  • FIG. 8 illustrates the HT format of the HT Control field in the MAC frame according to FIG. 6.
  • FIG. 9 illustrates the VHT format of the HT Control field in a wireless communication system to which the present invention can be applied.
  • FIG. 10 is a diagram illustrating a High Efficiency (HE) format PPDU according to an embodiment of the present invention.
  • HE High Efficiency
  • FIG. 11 is a diagram illustrating an HE format PPDU according to an embodiment of the present invention.
  • FIG. 12 is a diagram illustrating a HE format PPDU according to an embodiment of the present invention.
  • FIG. 13 is a diagram illustrating an HE format PPDU according to an embodiment of the present invention.
  • FIG. 17 illustrates a 1x HE-STF tone in channel-specific PPDU transmission according to an embodiment of the present invention.
  • FIG. 18 is a diagram illustrating a 2x HE-STF tone in channel-specific PPDU transmission according to an embodiment of the present invention.
  • 19 is a flowchart illustrating a PPDU transmission method of an STA device according to an embodiment of the present invention.
  • 20 is a block diagram of each STA apparatus according to an embodiment of the present invention.
  • CDMA code division multiple access
  • FDMA frequency division multiple access
  • TDMA time division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single carrier frequency division multiple access
  • GSM global system for mobile communications
  • GPRS general packet radio service
  • EDGE enhanced data rates for GSM evolution
  • OFDMA may be implemented with wireless technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), and the like.
  • UTRA is part of a universal mobile telecommunications system (UMTS).
  • 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA, and employs OFDMA in downlink and SC-FDMA in uplink.
  • LTE-A evolution of 3GPP LTE.
  • Embodiments of the present invention may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP and 3GPP2. That is, steps or parts which are not described to clearly reveal the technical spirit of the present invention among the embodiments of the present invention may be supported by the above documents. In addition, all terms disclosed in the present document can be described by the above standard document.
  • FIG. 1 is a diagram illustrating an example of an IEEE 802.11 system to which the present invention can be applied.
  • the IEEE 802.11 structure may be composed of a plurality of components, and a wireless communication system supporting a station (STA) mobility that is transparent to a higher layer may be provided by their interaction.
  • STA station
  • a basic service set (BSS) may correspond to a basic building block in an IEEE 802.11 system.
  • FIG. 1 there are three BSSs (BSS 1 to BSS 3) and two STAs are included as members of each BSS (STA 1 and STA 2 are included in BSS 1, and STA 3 and STA 4 are BSS 2. Included in, and STA 5 and STA 6 are included in BSS 3) by way of example.
  • an ellipse representing a BSS may be understood to represent a coverage area where STAs included in the BSS maintain communication. This area may be referred to as a basic service area (BSA).
  • BSA basic service area
  • the most basic type of BSS in an IEEE 802.11 system is an independent BSS (IBSS).
  • the IBSS may have a minimal form consisting of only two STAs.
  • BSS 3 of FIG. 1, which is the simplest form and other components are omitted, may correspond to a representative example of the IBSS. This configuration is possible when STAs can communicate directly.
  • this type of LAN may not be configured in advance, but may be configured when a LAN is required, which may be referred to as an ad-hoc network.
  • the membership of the STA in the BSS may be dynamically changed by turning the STA on or off, the STA entering or exiting the BSS region, or the like.
  • the STA may join the BSS using a synchronization process.
  • the STA In order to access all services of the BSS infrastructure, the STA must be associated with the BSS. This association may be set up dynamically and may include the use of a Distribution System Service (DSS).
  • DSS Distribution System Service
  • the direct STA-to-STA distance in an 802.11 system may be limited by physical layer (PHY) performance. In some cases, this distance limit may be sufficient, but in some cases, communication between STAs over longer distances may be required.
  • a distribution system (DS) may be configured to support extended coverage.
  • the DS refers to a structure in which BSSs are interconnected. Specifically, instead of the BSS independently as shown in FIG. 1, the BSS may exist as an extended type component of a network composed of a plurality of BSSs.
  • DS is a logical concept and can be specified by the characteristics of the Distribution System Medium (DSM).
  • DSM Distribution System Medium
  • the IEEE 802.11 standard logically distinguishes between wireless medium (WM) and distribution system medium (DSM). Each logical medium is used for a different purpose and is used by different components.
  • the definition of the IEEE 802.11 standard does not limit these media to the same or to different ones.
  • the plurality of media are logically different, and thus the flexibility of the structure of the IEEE 802.11 system (DS structure or other network structure) can be described. That is, the IEEE 802.11 system structure can be implemented in various ways, the corresponding system structure can be specified independently by the physical characteristics of each implementation.
  • the DS may support mobile devices by providing seamless integration of multiple BSSs and providing logical services for handling addresses to destinations.
  • the AP means an entity that enables access to the DS through the WM to the associated STAs and has STA functionality. Data movement between the BSS and the DS may be performed through the AP.
  • STA 2 and STA 3 illustrated in FIG. 1 have a functionality of STA, and provide a function of allowing associated STAs STA 1 and STA 4 to access the DS.
  • all APs basically correspond to STAs, all APs are addressable entities.
  • the address used by the AP for communication on the WM and the address used by the AP for communication on the DSM need not necessarily be the same.
  • Data transmitted from one of the STAs associated with an AP to the STA address of that AP may always be received at an uncontrolled port and processed by an IEEE 802.1X port access entity.
  • transmission data (or frame) may be transmitted to the DS.
  • a wireless network of arbitrary size and complexity may be composed of DS and BSSs.
  • this type of network is referred to as an extended service set (ESS) network.
  • the ESS may correspond to a set of BSSs connected to one DS. However, the ESS does not include a DS.
  • the ESS network is characterized by what appears to be an IBSS network at the Logical Link Control (LLC) layer. STAs included in the ESS may communicate with each other, and mobile STAs may move from one BSS to another BSS (within the same ESS) transparently to the LLC.
  • LLC Logical Link Control
  • BSSs can be partially overlapped, which is the form generally used to provide continuous coverage.
  • the BSSs may not be physically connected, and logically there is no limit to the distance between the BSSs.
  • the BSSs can be located at the same physical location, which can be used to provide redundancy.
  • one (or more) IBSS or ESS networks may be physically present in the same space as one or more ESS networks. This may be necessary if the ad-hoc network is operating at the location of the ESS network, if the IEEE 802.11 networks are physically overlapped by different organizations, or if two or more different access and security policies are required at the same location. It may correspond to an ESS network type in a case.
  • an STA is a device that operates according to Medium Access Control (MAC) / PHY regulations of IEEE 802.11. As long as the function of the STA is not distinguished from the AP individually, the STA may include an AP STA and a non-AP STA. However, when communication is performed between the STA and the AP, the STA may be understood as a non-AP STA. In the example of FIG. 1, STA 1, STA 4, STA 5, and STA 6 correspond to non-AP STAs, and STA 2 and STA 3 correspond to AP STAs.
  • MAC Medium Access Control
  • Non-AP STAs generally correspond to devices that users directly handle, such as laptop computers and mobile phones.
  • a non-AP STA includes a wireless device, a terminal, a user equipment (UE), a mobile station (MS), a mobile terminal, and a wireless terminal.
  • WTRU wireless transmit / receive unit
  • MTC machine-type communication
  • M2M machine-to-machine
  • the AP is a base station (BS), Node-B (Node-B), evolved Node-B (eNB), and Base Transceiver System (BTS) in other wireless communication fields.
  • BS base station
  • Node-B Node-B
  • eNB evolved Node-B
  • BTS Base Transceiver System
  • downlink means communication from the AP to the non-AP STA
  • uplink means communication from the non-AP STA to the AP.
  • the transmitter may be part of an AP and the receiver may be part of a non-AP STA.
  • a transmitter may be part of a non-AP STA and a receiver may be part of an AP.
  • FIG. 2 is a diagram illustrating a structure of a layer architecture of an IEEE 802.11 system to which the present invention may be applied.
  • the layer architecture of the IEEE 802.11 system may include a MAC sublayer and a PHY sublayer.
  • the PHY sublayer may be divided into a Physical Layer Convergence Procedure (PLCP) entity and a Physical Medium Dependent (PMD) entity.
  • PLCP Physical Layer Convergence Procedure
  • PMD Physical Medium Dependent
  • the PLCP entity plays a role of connecting a data frame with a MAC sublayer
  • the PMD entity plays a role of wirelessly transmitting and receiving data with two or more STAs.
  • Both the MAC sublayer and the PHY sublayer may include a management entity, which may be referred to as a MAC sublayer management entity (MLME) and a PHY sublayer management entity (PLME), respectively.
  • MLME MAC sublayer management entity
  • PLME PHY sublayer management entity
  • These management entities provide layer management service interfaces through the operation of layer management functions.
  • the MLME may be connected to the PLME to perform management operations of the MAC sublayer, and likewise the PLME may be connected to the MLME to perform management operations of the PHY sublayer.
  • a Station Management Entity may be present in each STA.
  • the SME is a management entity independent of each layer.
  • the SME collects layer-based state information from MLME and PLME or sets values of specific parameters of each layer.
  • the SME can perform these functions on behalf of general system management entities and implement standard management protocols.
  • the XX-GET.request primitive is used to request the value of a Management Information Base attribute (MIB attribute), and the XX-GET.confirm primitive, if the status is 'SUCCESS', returns the value of that MIB attribute. Otherwise, it returns with an error indication in the status field.
  • MIB attribute Management Information Base attribute
  • the XX-SET.request primitive is used to request that a specified MIB attribute be set to a given value. If the MIB attribute is meant for a particular action, this request requests the execution of that particular action. And, if the state is 'SUCCESS' XX-SET.confirm primitive, it means that the specified MIB attribute is set to the requested value. In other cases, the status field indicates an error condition. If this MIB attribute means a specific operation, this primitive can confirm that the operation was performed.
  • MIB attribute Management Information Base attribute
  • XX-GET.confirm primitive if the status is 'SUCCESS', returns the value of that MIB attribute. Otherwise, it returns with
  • the MAC sublayer includes a MAC header and a frame check sequence (FCS) in a MAC Service Data Unit (MSDU) or a fragment of an MSDU received from an upper layer (eg, an LLC layer).
  • FCS frame check sequence
  • MSDU MAC Service Data Unit
  • MPDU MAC Protocol Data Unit
  • A-MSDU aggregated MSDU
  • a plurality of MSDUs may be merged into a single A-MSDU (aggregated MSDU).
  • the MSDU merging operation may be performed at the MAC upper layer.
  • the A-MSDU is delivered to the PHY sublayer as a single MPDU (if not fragmented).
  • the PHY sublayer generates a physical protocol data unit (PPDU) by adding an additional field including information required by a physical layer transceiver to a physical service data unit (PSDU) received from the MAC sublayer. . PPDUs are transmitted over wireless media.
  • PPDU physical protocol data unit
  • the PSDU is substantially the same as the MPDU since the PHY sublayer is received from the MAC sublayer and the MPDU is transmitted by the MAC sublayer to the PHY sublayer.
  • A-MPDU aggregated MPDU
  • a plurality of MPDUs may be merged into a single A-MPDU.
  • the MPDU merging operation may be performed at the MAC lower layer.
  • A-MPDUs may be merged with various types of MPDUs (eg, QoS data, Acknowledge (ACK), Block ACK (BlockAck), etc.).
  • the PHY sublayer receives the A-MPDU as a single PSDU from the MAC sublayer. That is, the PSDU is composed of a plurality of MPDUs.
  • A-MPDUs are transmitted over the wireless medium in a single PPDU.
  • PPDU Physical Protocol Data Unit
  • IEEE 802.11 WLAN system to which the present invention can be applied.
  • FIG. 3 illustrates a non-HT format PPDU and a HT format PPDU of a wireless communication system to which the present invention can be applied.
  • Non-HT PPDUs may also be referred to as legacy PPDUs.
  • the non-HT format PPDU includes an L-STF (Legacy (or Non-HT) Short Training field), L-LTF (Legacy (or, Non-HT) Long Training field) and It includes a legacy format preamble and a data field composed of an L-SIG (Legacy (or Non-HT) SIGNAL) field.
  • L-STF Legacy (or Non-HT) Short Training field
  • L-LTF Legacy (or, Non-HT) Long Training field
  • L-SIG Legacy (or Non-HT) SIGNAL
  • the L-STF may include a short training orthogonal frequency division multiplexing symbol (OFDM) symbol.
  • L-STF can be used for frame timing acquisition, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization. .
  • the L-LTF may include a long training orthogonal frequency division multiplexing symbol.
  • L-LTF may be used for fine frequency / time synchronization and channel estimation.
  • the L-SIG field may be used to transmit control information for demodulation and decoding of the data field.
  • the L-SIG field may include information about a data rate and a data length.
  • FIG. 3B illustrates an HT-mixed format PPDU (HTDU) for supporting both an IEEE 802.11n system and an IEEE 802.11a / g system.
  • HTDU HT-mixed format PPDU
  • the HT mixed format PPDU includes a legacy format preamble including an L-STF, L-LTF, and L-SIG fields, an HT-SIG (HT-Signal) field, and an HT-STF (HT Short). Training field), HT-formatted preamble and data field including HT-LTF (HT Long Training field).
  • L-STF, L-LTF, and L-SIG fields mean legacy fields for backward compatibility, they are the same as non-HT formats from L-STF to L-SIG fields. Even if the L-STA receives the HT mixed PPDU, the L-STA may interpret the data field through the L-LTF, L-LTF, and L-SIG fields. However, the L-LTF may further include information for channel estimation that the HT-STA performs to receive the HT mixed PPDU and demodulate the L-SIG field and the HT-SIG field.
  • the HT-STA may know that it is an HT-mixed format PPDU using the HT-SIG field following the legacy field, and may decode the data field based on the HT-STA.
  • the HT-LTF field may be used for channel estimation for demodulation of the data field. Since IEEE 802.11n supports Single-User Multi-Input and Multi-Output (SU-MIMO), a plurality of HT-LTF fields may be configured for channel estimation for each data field transmitted in a plurality of spatial streams.
  • SU-MIMO Single-User Multi-Input and Multi-Output
  • the HT-LTF field includes data HT-LTF used for channel estimation for spatial streams and extension HT-LTF (additional used for full channel sounding). It can be configured as. Accordingly, the plurality of HT-LTFs may be equal to or greater than the number of spatial streams transmitted.
  • the L-STF, L-LTF, and L-SIG fields are transmitted first in order to receive the L-STA and acquire data. Thereafter, the HT-SIG field is transmitted for demodulation and decoding of data transmitted for the HT-STA.
  • the HT-SIG field is transmitted without performing beamforming so that the L-STA and HT-STA can receive the corresponding PPDU to acquire data, and then the HT-STF, HT-LTF and data fields transmitted are precoded. Wireless signal transmission is performed through.
  • the HT-STF field is transmitted to allow the STA to perform precoding to take into account the variable power due to precoding, and then the plurality of HT-LTF and data fields after that.
  • FIG. 3 (c) illustrates an HT-GF format PPDU (HT-GF) for supporting only an IEEE 802.11n system.
  • the HT-GF format PPDU includes HT-GF-STF, HT-LTF1, HT-SIG field, a plurality of HT-LTF2, and a data field.
  • HT-GF-STF is used for frame timing acquisition and AGC.
  • HT-LTF1 is used for channel estimation.
  • the HT-SIG field is used for demodulation and decoding of the data field.
  • HT-LTF2 is used for channel estimation for demodulation of data fields. Similarly, since HT-STA uses SU-MIMO, channel estimation is required for each data field transmitted in a plurality of spatial streams, and thus HT-LTF2 may be configured in plural.
  • the plurality of HT-LTF2 may be configured of a plurality of Data HT-LTF and a plurality of extended HT-LTF similarly to the HT-LTF field of the HT mixed PPDU.
  • the data field is a payload, and includes a service field, a SERVICE field, a scrambled PSDU field, tail bits, and padding bits. It may include. All bits of the data field are scrambled.
  • 3D illustrates a service field included in a data field.
  • the service field has 16 bits. Each bit is assigned from 0 to 15, and transmitted sequentially from bit 0. Bits 0 to 6 are set to 0 and used to synchronize the descrambler in the receiver.
  • the IEEE 802.11ac WLAN system supports downlink multi-user multiple input multiple output (MU-MIMO) transmission in which a plurality of STAs simultaneously access a channel in order to efficiently use a wireless channel.
  • MU-MIMO downlink multi-user multiple input multiple output
  • the AP may simultaneously transmit packets to one or more STAs that are paired with MIMO.
  • DL MU transmission (downlink multi-user transmission) refers to a technology in which an AP transmits a PPDU to a plurality of non-AP STAs through the same time resource through one or more antennas.
  • the MU PPDU refers to a PPDU that delivers one or more PSDUs for one or more STAs using MU-MIMO technology or OFDMA technology.
  • the SU PPDU means a PPDU having a format in which only one PSDU can be delivered or in which no PSDU exists.
  • control information transmitted to the STA may be relatively large compared to the size of 802.11n control information for MU-MIMO transmission.
  • An example of control information additionally required for MU-MIMO support includes information indicating the number of spatial streams received by each STA, information related to modulation and coding of data transmitted to each STA, and the like. Can be.
  • the size of transmitted control information may be increased according to the number of receiving STAs.
  • control information required for MU-MIMO transmission is required separately for common control information common to all STAs and specific STAs.
  • the data may be transmitted by being divided into two types of information of dedicated control information.
  • FIG. 4 illustrates a VHT format PPDU format of a wireless communication system to which the present invention can be applied.
  • VHT format PPDU VHT format PPDU
  • the VHT format PPDU includes a legacy format preamble including L-STF, L-LTF, and L-SIG fields, a VHT-SIG-A (VHT-Signal-A) field, and VHT-STF (VHT Short Training). Field), VHT Long Training Field (VHT-LTF), and VHT-SIG-B (VHT-Signal-B) field.
  • L-STF, L-LTF, and L-SIG indicate legacy fields for backward compatibility
  • the L-STF to L-SIG fields are the same as non-HT formats.
  • the L-LTF may further include information for channel estimation to be performed to demodulate the L-SIG field and the VHT-SIG-A field.
  • the L-STF, L-LTF, L-SIG field, and VHT-SIG-A field may be repeatedly transmitted in 20 MHz channel units. For example, when a PPDU is transmitted on four 20 MHz channels (i.e. 80 MHz bandwidth), the L-STF, L-LTF, L-SIG field, and VHT-SIG-A field are repeated on every 20 MHz channel. Can be sent.
  • the VHT-STA may know that it is a VHT format PPDU using the VHT-SIG-A field following the legacy field, and may decode the data field based on the VHT-STA.
  • the L-STF, L-LTF, and L-SIG fields are transmitted first in order to receive the L-STA and acquire data. Thereafter, the VHT-SIG-A field is transmitted for demodulation and decoding of data transmitted for the VHT-STA.
  • the VHT-SIG-A field is a field for transmitting control information common to the AP and MIMO paired VHT STAs, and may include control information for interpreting the received VHT format PPDU.
  • the VHT-SIG-A field may include a VHT-SIG-A1 field and a VHT-SIG-A2 field.
  • the VHT-SIG-A1 field includes information on channel bandwidth (BW) used, whether space time block coding (STBC) is applied, and group identification information for indicating a group of STAs grouped in MU-MIMO.
  • Group ID Group Identifier
  • NSTS space-time streams
  • Partial AID Partial Association Identifier
  • Transmit power save forbidden information can do.
  • the Group ID means an identifier assigned to the STA group to be transmitted to support MU-MIMO transmission, and may indicate whether the currently used MIMO transmission method is MU-MIMO or SU-MIMO.
  • the VHT-SIG-A2 field contains information on whether a short guard interval (GI) is used, forward error correction (FEC) information, information on modulation and coding scheme (MCS) for a single user, and multiple information.
  • GI short guard interval
  • FEC forward error correction
  • MCS modulation and coding scheme
  • Information on the type of channel coding for the user beamforming-related information, redundancy bits for cyclic redundancy checking (CRC), tail bits of convolutional decoder, and the like. Can be.
  • VHT-STF is used to improve the performance of AGC estimation in MIMO transmission.
  • VHT-LTF is used by the VHT-STA to estimate the MIMO channel. Since the VHT WLAN system supports MU-MIMO, the VHT-LTF may be set as many as the number of spatial streams in which a PPDU is transmitted. In addition, if full channel sounding is supported, the number of VHT-LTFs may be greater.
  • the VHT-SIG-B field includes dedicated control information required for a plurality of MU-MIMO paired VHT-STAs to receive a PPDU and acquire data. Accordingly, the VHT-STA may be designed to decode the VHT-SIG-B only when the common control information included in the VHT-SIG-A field indicates the MU-MIMO transmission currently received. On the other hand, if the common control information indicates that the currently received PPDU is for a single VHT-STA (including SU-MIMO), the STA may be designed not to decode the VHT-SIG-B field.
  • the VHT-SIG-B field may include information on modulation, encoding, and rate-matching of each VHT-STA.
  • the size of the VHT-SIG-B field may vary depending on the type of MIMO transmission (MU-MIMO or SU-MIMO) and the channel bandwidth used for PPDU transmission.
  • information indicating a bit size of a data field constituting the PPDU and / or indicating a bit stream size constituting a specific field May be included in the VHT-SIG-A field.
  • the L-SIG field may be used to effectively use the PPDU format.
  • a length field and a rate field included in the L-SIG field and transmitted may be used to provide necessary information.
  • MPDU MAC Protocol Data Unit
  • A-MPDU Aggregate MAC Protocol Data Unit
  • the data field is a payload and may include a service field, a scrambled PSDU, tail bits, and padding bits.
  • the STA Since the formats of various PPDUs are mixed and used as described above, the STA must be able to distinguish the formats of the received PPDUs.
  • the meaning of distinguishing a PPDU may have various meanings.
  • the meaning of identifying the PPDU may include determining whether the received PPDU is a PPDU that can be decoded (or interpreted) by the STA.
  • the meaning of distinguishing the PPDU may mean determining whether the received PPDU is a PPDU supported by the STA.
  • the meaning of distinguishing the PPDU may also be interpreted to mean what information is transmitted through the received PPDU.
  • FIG. 5 is a diagram illustrating a constellation for distinguishing a format of a PPDU of a wireless communication system to which the present invention can be applied.
  • FIG. 5A illustrates a constellation of an L-SIG field included in a non-HT format PPDU
  • FIG. 5B illustrates a phase rotation for HT mixed format PPDU detection
  • 5C illustrates phase rotation for VHT format PPDU detection.
  • Phase is used. That is, the STA may distinguish the PPDU format based on the phase of the constellation of the OFDM symbol transmitted after the L-SIG field and / or the L-SIG field of the received PPDU.
  • binary phase shift keying (BPSK) is used for an OFDM symbol constituting an L-SIG field.
  • the STA determines whether it is an L-SIG field. That is, the STA attempts to decode based on the constellation as illustrated in (a) of FIG. 5. If the STA fails to decode, it may be determined that the corresponding PPDU is an HT-GF format PPDU.
  • the phase of the constellation of OFDM symbols transmitted after the L-SIG field may be used. That is, the modulation method of OFDM symbols transmitted after the L-SIG field may be different, and the STA may distinguish the PPDU format based on the modulation method for the field after the L-SIG field of the received PPDU.
  • the phase of two OFDM symbols transmitted after the L-SIG field in the HT mixed format PPDU may be used.
  • the phases of OFDM symbol # 1 and OFDM symbol # 2 corresponding to the HT-SIG field transmitted after the L-SIG field in the HT mixed format PPDU are rotated by 90 degrees in the counterclockwise direction. That is, quadrature binary phase shift keying (QBPSK) is used as a modulation method for OFDM symbol # 1 and OFDM symbol # 2.
  • QBPSK constellation may be a constellation rotated by 90 degrees in a counterclockwise direction based on the BPSK constellation.
  • the STA attempts to decode the first OFDM symbol and the second OFDM symbol corresponding to the HT-SIG field transmitted after the L-SIG field of the received PPDU based on the properties as shown in FIG. If the STA succeeds in decoding, it is determined that the corresponding PPDU is an HT format PPDU.
  • the phase of the constellation of the OFDM symbol transmitted after the L-SIG field may be used.
  • the phase of two OFDM symbols transmitted after the L-SIG field in the VHT format PPDU may be used.
  • phase of the OFDM symbol # 1 corresponding to the VHT-SIG-A field after the L-SIG field in the VHT format PPDU is not rotated, but the phase of the OFDM symbol # 2 is rotated by 90 degrees counterclockwise. . That is, BPSK is used for the modulation method for OFDM symbol # 1 and QBPSK is used for the modulation method for OFDM symbol # 2.
  • the STA attempts to decode the first OFDM symbol and the second OFDM symbol corresponding to the VHT-SIG field transmitted after the L-SIG field of the received PPDU based on the properties as shown in the example of FIG. If the STA succeeds in decoding, it may be determined that the corresponding PPDU is a VHT format PPDU.
  • the STA may determine that the corresponding PPDU is a non-HT format PPDU.
  • FIG. 6 illustrates a MAC frame format of an IEEE 802.11 system to which the present invention can be applied.
  • a MAC frame (ie, an MPDU) includes a MAC header, a frame body, and a frame check sequence (FCS).
  • FCS frame check sequence
  • MAC Header includes Frame Control field, Duration / ID field, Address 1 field, Address 2 field, Address 3 field, Sequence control It is defined as an area including a Control field, an Address 4 field, a QoS Control field, and an HT Control field.
  • the Frame Control field includes information on the MAC frame characteristic. A detailed description of the Frame Control field will be given later.
  • the Duration / ID field may be implemented to have different values depending on the type and subtype of the corresponding MAC frame.
  • the Duration / ID field is an AID (association identifier) of the STA that transmitted the frame. It may be set to include. Otherwise, the Duration / ID field may be set to have a specific duration value according to the type and subtype of the corresponding MAC frame.
  • the Duration / ID fields included in the MAC header may be set to have the same value.
  • the Address 1 to Address 4 fields include a BSSID, a source address (SA), a destination address (DA), a transmission address (TA) indicating a transmission STA address, and a reception address indicating a destination STA address (TA).
  • SA source address
  • DA destination address
  • TA transmission address
  • TA reception address indicating a destination STA address
  • RA It is used to indicate Receiving Address.
  • the address field implemented as a TA field may be set to a bandwidth signaling TA value, in which case, the TA field may indicate that the corresponding MAC frame contains additional information in the scrambling sequence.
  • the bandwidth signaling TA may be represented by the MAC address of the STA transmitting the corresponding MAC frame, but the Individual / Group bit included in the MAC address may be set to a specific value (for example, '1'). Can be.
  • the Sequence Control field is set to include a sequence number and a fragment number.
  • the sequence number may indicate a sequence number allocated to the corresponding MAC frame.
  • the fragment number may indicate the number of each fragment of the corresponding MAC frame.
  • the QoS Control field contains information related to QoS.
  • the QoS Control field may be included when indicating a QoS data frame in a subtype subfield.
  • the HT Control field includes control information related to the HT and / or VHT transmission / reception schemes.
  • the HT Control field is included in the Control Wrapper frame. In addition, it exists in the QoS data frame and the management frame in which the order subfield value is 1.
  • the frame body is defined as a MAC payload, and data to be transmitted in a higher layer is located, and has a variable size.
  • the maximum MPDU size may be 11454 octets
  • the maximum PPDU size may be 5.484 ms.
  • FCS is defined as a MAC footer and is used for error detection of MAC frames.
  • the first three fields (Frame Control field, Duration / ID field and Address 1 field) and the last field (FCS field) constitute the minimum frame format and are present in every frame. Other fields may exist only in a specific frame type.
  • FIG. 7 is a diagram illustrating a Frame Control field in a MAC frame in a wireless communication system to which the present invention can be applied.
  • the Frame Control field includes a Protocol Version subfield, a Type subfield, a Subtype subfield, a To DS subfield, a From DS subfield, and more fragments.
  • the Protocol Version subfield may indicate the version of the WLAN protocol applied to the corresponding MAC frame.
  • the Type subfield and the Subtype subfield may be set to indicate information for identifying a function of a corresponding MAC frame.
  • the type of the MAC frame may include three frame types: a management frame, a control frame, and a data frame.
  • Each frame type may be further divided into subtypes.
  • control frames include request to send (RTS) frames, clear-to-send (CTS) frames, acknowledgment (ACK) frames, PS-Poll frames, content free (End) frames, CF End + CF-ACK frame, Block Acknowledgment request (BAR) frame, Block Acknowledgment (BA) frame, Control Wrapper (Control + HTcontrol) frame, VHT null data packet notification (NDPA) It may include a Null Data Packet Announcement and a Beamforming Report Poll frame.
  • Management frames include beacon frames, announcement traffic indication message (ATIM) frames, disassociation frames, association request / response frames, reassociation requests / responses Response frame, Probe Request / Response frame, Authentication frame, Deauthentication frame, Action frame, Action No ACK frame, Timing Advertisement It may include a frame.
  • ATIM announcement traffic indication message
  • disassociation frames association request / response frames
  • reassociation requests / responses Response frame Probe Request / Response frame
  • Authentication frame Deauthentication frame
  • Action frame Action No ACK frame
  • Timing Advertisement It may include a frame.
  • the To DS subfield and the From DS subfield may include information necessary to interpret the Address 1 field or the Address 4 field included in the corresponding MAC frame header.
  • both the To DS subfield and the From DS subfield are set to '0'.
  • the To DS subfield and the From DS subfield are set to '1' and '0' in order if the frame is a QoS Management frame (QMF), and in order if the frame is not QMF. Both can be set to '0', '0'.
  • QMF QoS Management frame
  • the More Fragments subfield may indicate whether there is a fragment to be transmitted following the corresponding MAC frame. If there is another fragment of the current MSDU or MMPDU, it may be set to '1', otherwise it may be set to '0'.
  • the Retry subfield may indicate whether the corresponding MAC frame is due to retransmission of a previous MAC frame. In case of retransmission of the previous MAC frame, it may be set to '1', otherwise it may be set to '0'.
  • the power management subfield may indicate a power management mode of the STA. If the value of the Power Management subfield is '1', it may indicate that the STA switches to the power save mode.
  • the More Data subfield may indicate whether there is an additional MAC frame to be transmitted. In addition, if there is a MAC frame to be transmitted, it may be set to '1', otherwise it may be set to '0'.
  • the Protected Frame subfield may indicate whether the frame body field is encrypted. If the Frame Body field includes information processed by an encrypted encapsulation algorithm, it may be set to '1', otherwise it may be set to '0'.
  • each field described above corresponds to an example of fields that may be included in the MAC frame, but is not limited thereto. That is, each field described above may be replaced with another field or additional fields may be further included, and all fields may not be necessarily included.
  • FIG. 8 illustrates the HT format of the HT Control field in the MAC frame according to FIG. 6.
  • the HT Control field includes a VHT subfield, an HT Control Middle subfield, an AC Constraint subfield, and a Reverse Direction Grant (RDG) / More PPDU (More PPDU). It may consist of subfields.
  • RDG Reverse Direction Grant
  • More PPDU More PPDU
  • the HT Control Middle subfield may be implemented to have a different format according to the indication of the VHT subfield. A more detailed description of the HT Control Middle subfield will be given later.
  • the AC Constraint subfield indicates whether a mapped AC (Access Category) of a reverse direction (RD) data frame is limited to a single AC.
  • the RDG / More PPDU subfield may be interpreted differently depending on whether the corresponding field is transmitted by the RD initiator or the RD responder.
  • the RDG / More PPDU field is set to '1' if the RDG exists, and set to '0' if the RDG does not exist.
  • the RDG responder When transmitted by the RD responder, it is set to '1' if the PPDU including the corresponding subfield is the last frame transmitted by the RD responder, and set to '0' when another PPDU is transmitted.
  • the HT Control Middle subfield of the HT Control field for the HT includes a link adaptation subfield, a calibration position subfield, a calibration sequence subfield, a reserved subfield, and channel state information. And / or (CSI / Steering: Channel State Information / Steering) subfield, HT NDP Announcement (HT NDP Announcement) subfield, and Reserved subfield.
  • the Link Adaptation subfield is a training request (TRQ) subfield, an MCS request or antenna selection indication (MAI: MCS (Modulation and Coding Scheme) Request or ASEL (Antenna Selection) Indication) subfield, and an MCS feedback sequence indication (MFSI).
  • MCS Feedback and Antenna Selection Command / data (MFB / ASELC) subfields are training requests (TRQ) subfields, an MCS request or antenna selection indication (MAI: MCS (Modulation and Coding Scheme) Request or ASEL (Antenna Selection) Indication) subfield, and an MCS feedback sequence indication (MFSI).
  • MCS Feedback and Antenna Selection Command / data (MFB / ASELC) subfields MCS Feedback and Antenna Selection Command / data
  • the TRQ subfield is set to 1 when the responder requests sounding PPDU transmission and is set to 0 when the responder does not request sounding PPDU transmission.
  • the MAI subfield is set to 14, this indicates an ASEL indication, and the MFB / ASELC subfield is interpreted as an antenna selection command / data. Otherwise, the MAI subfield indicates an MCS request and the MFB / ASELC subfield is interpreted as MCS feedback.
  • the MAI subfield When the MAI subfield indicates an MCS Request (MRQ: MCS Request), it is interpreted that the MAI subfield is composed of an MRQ (MCS request) and an MSI (MRQ sequence identifier).
  • MCS request MCS request
  • MSI MRQ sequence identifier
  • the MRQ subfield is set to '1' if MCS feedback is requested and set to '0' if MCS feedback is not requested.
  • the MSI subfield When the MRQ subfield is '1', the MSI subfield includes a sequence number for specifying an MCS feedback request.
  • the MSI subfield When the MRQ subfield is '0', the MSI subfield is set to a reserved bit.
  • Each of the above-described subfields corresponds to an example of subfields that may be included in the HT control field, and may be replaced with another subfield or may further include additional subfields.
  • FIG. 9 illustrates the VHT format of the HT Control field in a wireless communication system to which the present invention can be applied.
  • the HT Control field includes a VHT subfield, a HT Control Middle subfield, an AC Constraint subfield, and a Reverse Direction Grant (RDG) / More PPDU (More PPDU). It may consist of subfields.
  • RDG Reverse Direction Grant
  • More PPDU More PPDU
  • VHT 1
  • VHT Control field 1
  • the HT Control Middle subfield may be implemented to have a different format according to the indication of the VHT subfield.
  • the HT Control Middle subfield of the HT Control field for VHT includes a reserved bit, a Modulation and Coding Scheme feedback request (MRQ) subfield, and an MRQ Sequence Identifier (MSI).
  • STBC Space-time block coding
  • MCS MCS feedback sequence identifier
  • LSB Least Significant Bit
  • MSB MCS Feedback
  • MSB Group ID Most Significant Bit
  • Coding Type Subfield Feedback Transmission Type (FB Tx Type: Feedback transmission type) subfield and voluntary MFB (Unsolicited MFB) subfield.
  • the MFB subfield may include a VHT number of space time streams (NUM_STS) subfield, a VHT-MCS subfield, a bandwidth (BW) subfield, and a signal to noise ratio (SNR). It may include subfields.
  • NUM_STS VHT number of space time streams
  • BW bandwidth
  • SNR signal to noise ratio
  • the NUM_STS subfield indicates the number of recommended spatial streams.
  • the VHT-MCS subfield indicates a recommended MCS.
  • the BW subfield indicates bandwidth information related to the recommended MCS.
  • the SNR subfield indicates the average SNR value on the data subcarrier and spatial stream.
  • each field described above corresponds to an example of fields that may be included in the MAC frame, but is not limited thereto. That is, each field described above may be replaced with another field or additional fields may be further included, and all fields may not be necessarily included.
  • next generation WLAN system is a next generation WIFI system, and may be described as an example of IEEE 802.11ax as an embodiment of the next generation WIFI system.
  • HE High Efficiency
  • frames, PPDUs, and the like of the system may be referred to as HE frames, HE PPDUs, HE-SIG fields, HE-STFs, and HE-LTFs. have.
  • the description of the existing WLAN system such as the above-described VHT system may be applied to the HE system, which is not further described below.
  • VHT-SIG A field VHT-STF, VHT-LTF and HE-SIG-B fields described above for the HE-SIG A field, HE-STF, HE-LTF and HE-SIG-B fields. Description may apply.
  • the HE frame and the preamble of the proposed HE system may be used only for other wireless communication or cellular systems.
  • the HE STA may be a non-AP STA or an AP STA as described above. Although referred to as STA in the following specification, such a STA device may represent an HE STA device.
  • the HE format PPDU may be largely composed of a legacy part (L-part), an HE part (HE-part), and an HE data (HE-data) field.
  • L-part legacy part
  • HE-part HE part
  • HE-data HE data field
  • FIG. 10 is a diagram illustrating a High Efficiency (HE) format PPDU according to an embodiment of the present invention.
  • HE High Efficiency
  • a HE format PPDU for HEW may be largely composed of a legacy part (L-part) and an HE part (HE-part).
  • the L-part is composed of an L-STF field, an L-LTF field, and an L-SIG field in the same manner as the conventional WLAN system maintains.
  • the L-STF field, L-LTF field, and L-SIG field may be referred to as a legacy preamble.
  • the HE-part is a part newly defined for the 802.11ax standard, and may include a HE-SIG field, a HE preamble, and a HE-data field.
  • the HE-preamble may include a HE-STF field and a HE-LTF field.
  • HE-preamble may include a HE-STF field and a HE-LTF field.
  • HE-preamble not only the HE-STF field and the HE-LTF field but also the HE-SIG field may be collectively referred to as HE-preamble.
  • FIG. 10 illustrates the order of the HE-SIG field, the HE-STF field, and the HE-LTF field, they may be configured in a different order.
  • the L-part, the HE-SIG field, and the HE-preamble may be collectively referred to as a physical preamble (PHY).
  • PHY physical preamble
  • the HE-SIG field may include information (eg, OFDMA, UL MU MIMO, enhanced MCS, etc.) for decoding the HE-data field.
  • information eg, OFDMA, UL MU MIMO, enhanced MCS, etc.
  • L-part and HE-part may have different fast fourier transform (FFT) sizes, and may use different cyclic prefixes (CP). That is, the L-part and the HE-part (particularly, the HE-preamble and the HE-data) may have different subcarrier frequency spacings.
  • FFT fast fourier transform
  • CP cyclic prefixes
  • the 802.11ax system can use four times larger (4x) FFT size than legacy WLAN systems. That is, the L-part may be configured with a 1x symbol structure, and the HE-part (particularly, HE-preamble and HE-data) may be configured with a 4x symbol structure.
  • 1x, 2x, 4x size FFT refers to the size relative to the legacy WLAN system (eg, IEEE 802.11a, 802.11n, 802.11ac, etc.).
  • the FFT size used for the L-part is 64, 128, 256, and 512 at 20 MHz, 40 MHz, 80 MHz, and 160 MHz, respectively
  • the FFT size used for the HE-part is 256 at 20 MHz, 40 MHz, 80 MHz, and 160 MHz, respectively. , 512, 1024, 2048.
  • the FFT size is larger than that of the legacy WLAN system, the number of subcarriers per unit frequency is increased because the subcarrier frequency spacing is smaller, but the OFDM symbol length is longer.
  • the use of a larger FFT size means that the subcarrier spacing becomes narrower, and similarly, an Inverse Discrete Fourier Transform (IDFT) / Discrete Fourier Transform (DFT) period is increased.
  • IDFT Inverse Discrete Fourier Transform
  • DFT Discrete Fourier Transform
  • the IDFT / DFT period may mean a symbol length excluding the guard period (GI) in the OFDM symbol.
  • the subcarrier spacing of the HE-part is 1/4 of the subcarrier spacing of the L-part.
  • the ID-FT / DFT period of the HE-part is four times the IDFT / DFT period of the L-part.
  • the GI can be one of 0.8 ⁇ s, 1.6 ⁇ s, 3.2 ⁇ s, so the OFDM symbol length (or symbol interval) of the HE-part including the GI is 13.6 ⁇ s, 14.4 ⁇ s, 16 according to the GI. It can be
  • FIG. 10 illustrates a case in which the HE-SIG field has a 1x symbol structure
  • the HE-SIG field may also have a 4x symbol structure like HE-preamble and HE-data.
  • the HE-SIG may be divided into an HE-SIG A field and an HE-SIG B field.
  • the FFT size per unit frequency may be larger after HE-SIG B. That is, after the HE-SIG B, the OFDM symbol length may be longer than the L-part.
  • the HE format PPDU for the WLAN system to which the present invention can be applied may be transmitted through at least one 20 MHz channel.
  • the HE format PPDU may be transmitted in a 40 MHz, 80 MHz, or 160 MHz frequency band through a total of four 20 MHz channels. This will be described in more detail with reference to the drawings below.
  • FIG. 11 is a diagram illustrating an HE format PPDU according to an embodiment of the present invention.
  • 11 illustrates a PPDU format when 80 MHz is allocated to one STA (or OFDMA resource units are allocated to a plurality of STAs within 80 MHz) or when different streams of 80 MHz are allocated to a plurality of STAs.
  • L-STF, L-LTF, and L-SIG may be transmitted as OFDM symbols generated based on 64 FFT points (or 64 subcarriers) in each 20MHz channel.
  • the HE-SIG A field may include common control information transmitted in common to STAs receiving a PPDU.
  • the HE-SIG A field may be transmitted in one to three OFDM symbols.
  • the HE-SIG A field is copied in units of 20 MHz and includes the same information.
  • the HE-SIG-A field informs the total bandwidth information of the system.
  • Table 1 is a table illustrating information included in the HE-SIG A field.
  • each field described above corresponds to an example of fields that may be included in the PPDU, but is not limited thereto. That is, each field described above may be replaced with another field or additional fields may be further included, and all fields may not be necessarily included.
  • the HE-SIG B field may include user-specific information required for each STA to receive its own data (eg, PSDU).
  • PSDU user-specific information required for each STA to receive its own data
  • the HE-SIG B field may be transmitted in one or two OFDM symbols.
  • the HE-SIG B field may include information on the modulation and coding scheme (MCS) of the corresponding PSDU and the length of the corresponding PSDU.
  • MCS modulation and coding scheme
  • the L-STF, L-LTF, L-SIG, and HE-SIG A fields may be repeatedly transmitted in units of 20 MHz channels. For example, when a PPDU is transmitted on four 20 MHz channels (ie, an 80 MHz band), the L-STF, L-LTF, L-SIG, and HE-SIG A fields may be repeatedly transmitted on every 20 MHz channel. .
  • legacy STAs supporting legacy IEEE 802.11a / g / n / ac may not be able to decode the HE PPDU.
  • the L-STF, L-LTF, and L-SIG fields are transmitted through a 64 FFT on a 20 MHz channel so that the legacy STA can receive them.
  • the L-SIG field may occupy one OFDM symbol, one OFDM symbol time is 4 ms, and a GI may be 0.8 ms.
  • HE-STF is used to improve the performance of AGC estimation in MIMO transmission.
  • the FFT size for each frequency unit can be made larger from the HE-STF. For example, 256 FFTs may be used in a 20 MHz channel, 512 FFTs may be used in a 40 MHz channel, and 1024 FFTs may be used in an 80 MHz channel. As the FFT size increases, the number of OFDM subcarriers per unit frequency increases because the interval between OFDM subcarriers becomes smaller, but the OFDM symbol time becomes longer. In order to improve the efficiency of the system, the length of the GI after the HE-STF may be set equal to the length of the GI of the HE-SIG A.
  • the HE-SIG A field may include information required for the HE STA to decode the HE PPDU.
  • the HE-SIG A field may be transmitted through a 64 FFT in a 20 MHz channel so that both the legacy STA and the HE STA can receive it. This is because the HE STA can receive not only the HE format PPDU but also the existing HT / VHT format PPDU, and the legacy STA and the HE STA must distinguish between the HT / VHT format PPDU and the HE format PPDU.
  • FIG. 12 is a diagram illustrating a HE format PPDU according to an embodiment of the present invention.
  • the FFT size per unit frequency may be larger from the HE-STF (or HE-SIG B).
  • 256 FFTs may be used in a 20 MHz channel
  • 512 FFTs may be used in a 40 MHz channel
  • 1024 FFTs may be used in an 80 MHz channel.
  • the HE-SIG B field may include information specific to each STA, but may be encoded over the entire band (ie, indicated by the HE-SIG-A field). That is, the HE-SIG B field includes information on all STAs and is received by all STAs.
  • the HE-SIG B field may inform frequency bandwidth information allocated to each STA and / or stream information in a corresponding frequency band.
  • the HE-SIG-B may be allocated 20 MHz for STA 1, 20 MHz for STA 2, 20 MHz for STA 3, and 20 MHz for STA 4.
  • STA 1 and STA 2 may allocate 40 MHz, and STA 3 and STA 4 may then allocate 40 MHz.
  • STA 1 and STA 2 may allocate different streams, and STA 3 and STA 4 may allocate different streams.
  • the HE-SIG C field may be added to the example of FIG. 12.
  • information on all STAs may be transmitted over the entire band, and control information specific to each STA may be transmitted in units of 20 MHz through the HE-SIG-C field.
  • the HE-SIG-B field may be transmitted in units of 20 MHz in the same manner as the HE-SIG-A field without transmitting over the entire band. This will be described with reference to the drawings below.
  • FIG. 13 is a diagram illustrating an HE format PPDU according to an embodiment of the present invention.
  • the HE-SIG B field is not transmitted over the entire band, but is transmitted in 20 MHz units in the same manner as the HE-SIG A field. However, at this time, the HE-SIG-B is encoded and transmitted in 20 MHz units differently from the HE-SIG A field, but may not be copied and transmitted in 20 MHz units.
  • the FFT size per unit frequency may be larger from the HE-STF (or HE-SIG B).
  • 256 FFTs may be used in a 20 MHz channel
  • 512 FFTs may be used in a 40 MHz channel
  • 1024 FFTs may be used in an 80 MHz channel.
  • the HE-SIG A field is duplicated and transmitted in units of 20 MHz.
  • the HE-SIG B field may inform frequency bandwidth information allocated to each STA and / or stream information in a corresponding frequency band. Since the HE-SIG B field includes information about each STA, information about each STA may be included for each HE-SIG B field in units of 20 MHz. In this case, in the example of FIG. 13, 20 MHz is allocated to each STA. For example, when 40 MHz is allocated to the STA, the HE-SIG-B field may be copied and transmitted in units of 20 MHz.
  • the data field is a payload and may include a service field, a scrambled PSDU, tail bits, and padding bits.
  • the HE format PPDU as shown in FIGS. 10 to 13 may be identified through a RL-SIG (Repeated L-SIG) field which is a repetitive symbol of the L-SIG field.
  • the RL-SIG field is inserted before the HE SIG-A field, and each STA may identify the format of the received PPDU as the HE format PPDU using the RL-SIG field.
  • DL MU transmission downlink multi-user transmission
  • UL MU transmission uplink multi-user transmission
  • Such DL MU transmission or UL MU transmission may be multiplexed in a frequency domain or a spatial domain.
  • different frequency resources eg, subcarriers or tones
  • OFDMA orthogonal frequency division multiplexing
  • different spatial streams may be allocated as downlink or uplink resources for each of the plurality of STAs.
  • a transmission expression through different spatial streams may be referred to as 'DL / UL MU MIMO' transmission.
  • the HE system intends to use an FFT size four times larger than the conventional WLAN system for average throughput enhancement and outdoor robust transmission of the outdoor.
  • the symbol period of the symbol to which the 4x FFT scheme is applied is quadrupled. This is an example of using a 4x FFT size, in which the entire bandwidth is constant and the subcarrier spacing is used 1/4 times. Since the spacing between subcarriers is 1/4, The period can be four times.
  • the 1x FFT size which is the basis of the 4x FFT size, may be the FFT size of the VHT system (IEEE 802.11ac). Accordingly, the 1x FFT size, which is a reference of the 4x FFT size, may correspond to the FFT size of the legacy preamble portions L-STF, L-LTF, and L-SIG of the frame.
  • the period of one preamble for 1x FFT can be expressed by adding IDFT / DFT period 3.2us and guard interval symbol period, 4us (3.2 + 0.8) for long guard interval period (Long GI symbol interval), short guard interval In the case of a short GI symbol interval, it may be 3.6us (3.2 + 0,4).
  • the symbol period of the data portion is 3.2us, if the 4x FFT scheme is applied in the HE system, one symbol period may be 12.8us. Alternatively, the symbol period of the data portion may be represented as 12.8us at 4 times the IDFT / DFT period.
  • an OFDMA scheme may be used to transmit and receive more data to a plurality of STAs at the same time.
  • Orthogonal Frequency Division Multiple Access (OFDMA) is a multi-user version of an OFDM digital modulation scheme.
  • the OFDMA scheme represents a scheme in which a plurality of users are allocated a subset of subcarriers as resource units instead of monopolizing a multicarrier, that is, a subcarrier according to the OFDM scheme.
  • a subcarrier (or subcarrier) used in OFDMA may be referred to as a tone, and a tone plan for how to allocate these tones to each STA and how to arrange leftover tones allocated to each STA It will be described below.
  • the following "channel” refers to the transmission channel (or bandwidth of the PPDU) of the PPDU. That is, the 20 MHz channel means that the bandwidth of the transmitted PPDU is 20 MHz, the 40 MHz channel means that the bandwidth of the transmitted PPDU is 40 MHz, and the 80 MHz channel may mean that the bandwidth of the transmitted PPDU is 80 MHz.
  • a plurality of resource units may be defined in units of n tones (or subcarriers) within a PPDU bandwidth.
  • the resource unit means an allocation unit of frequency resources for DL / UL OFDMA transmission.
  • One or more resource units may be allocated to one STA as DL / UL frequency resources, and different resource units may be allocated to the plurality of STAs, respectively.
  • Seven DC tones may be located in the center frequency region of the 20 MHz PPDU bandwidth.
  • six left guard tones and five right guard tones may be located at both sides of the 20 MHz PPDU bandwidth.
  • one resource unit may be configured of 26 tones (26 ton resource units). In this case, four leftover tones may be present in the 20 MHz PPDU bandwidth as shown in FIG. 14 (a) adjacent to the 26-tone resource unit.
  • one resource unit may be composed of 52 tones (52 ton resource unit) or 26 tones. In this case, four leftover tones may be present in the 20MHz PPDU bandwidth as shown in FIG. 14 (b) adjacent to the 26t / 52t resource unit.
  • one resource unit may be composed of 106 tones (106 ton resource unit) or 26 tones.
  • one resource unit may be configured of 242 tones (242 ton resource unit).
  • a resource unit When a resource unit is configured as shown in FIG. 14A, up to nine STAs may be supported for DL / UL OFDMA transmission in a 20 MHz band. In addition, when a resource unit is configured as shown in FIG. 14B, up to five STAs may be supported for DL / UL OFDMA transmission in a 20 MHz band. In addition, when the resource unit is configured as shown in FIG. 14 (c), up to three STAs may be supported for DL / UL OFDMA transmission in the 20 MHz band. In addition, when a resource unit is configured as shown in 21 (d), a 20 MHz band may be allocated to one STA.
  • the resource unit configuration scheme of FIG. 14 (a) to FIG. 14 (d) may be applied based on the number of STAs participating in DL / UL OFDMA transmission and / or the amount of data transmitted or received by the STA. Alternatively, the resource unit configuration scheme in which FIGS. 14 (a) to 14 (d) are combined may be applied.
  • 15 illustrates a case where the PPDU bandwidth is 40 MHz.
  • DC tones may be located in the center frequency region of the 40 MHz PPDU bandwidth.
  • 12 left guard tones and 11 light guard tones may be located at both sides of the 40 MHz PPDU bandwidth.
  • one resource unit may consist of 26 tones. In this case, 16 leftover tones may be present in the 40 MHz PPDU bandwidth as shown in FIG. 15A adjacent to the 26-tone resource unit.
  • one resource unit may be composed of 52 tones or 26 tones. In this case, 16 leftover tones may be present in the 40 MHz PPDU bandwidth as shown in FIG. 15 (b) adjacent to the 26 ton / 52 ton resource unit.
  • one resource unit may be composed of 106 tones or 26 tones.
  • one resource unit may be configured with 242 tones.
  • one resource unit may be configured of 484 tones (484 ton resource unit).
  • up to 18 STAs may be supported for DL / UL OFDMA transmission in a 40 MHz band.
  • up to 10 STAs may be supported for DL / UL OFDMA transmission in the 40 MHz band.
  • a resource unit is configured as shown in FIG. 15C
  • up to six STAs may be supported for DL / UL OFDMA transmission in a 40 MHz band.
  • the resource unit is configured as shown in 15 (d)
  • up to two STAs may be supported for DL / UL OFDMA transmission in the 40 MHz band.
  • the corresponding resource unit may be allocated to one STA for SU DL / UL transmission in the 40 MHz band.
  • the resource unit configuration method of FIG. 15 (a) to FIG. 15 (e) may be applied based on the number of STAs participating in DL / UL OFDMA transmission and / or the amount of data transmitted or received by the STA.
  • the resource unit configuration scheme in which FIGS. 15 (a) to 15 (e) are combined may be applied.
  • 16 illustrates a case where the PPDU bandwidth is 80 MHz.
  • Seven DC tones may be located in the center frequency region of the 80 MHz PPDU bandwidth. However, when 80 MHz PPDU bandwidth is allocated to one STA (that is, when a resource unit composed of 996 tones is allocated to one STA), five DC tones may be located in the center frequency region. In addition, 12 left guard tones and 11 light guard tones may be located at both sides of the 80 MHz PPDU bandwidth.
  • one resource unit may consist of 26 tones. In this case, 32 leftover tones may be present in the 80 MHz PPDU bandwidth as shown in FIG. 16 (a) adjacent to the 26-tone resource unit.
  • one resource unit may be composed of 52 tones or 26 tones. In this case, 32 leftover tones may be present in the 80 MHz PPDU bandwidth as shown in FIG. 16 (b) adjacent to the 26 ton / 52 ton resource unit.
  • one resource unit may consist of 106 tones or 26 tones.
  • one resource unit may be composed of 242 tones or 26 tones.
  • one resource unit may consist of 484 tones or 26 tones.
  • one resource unit may be configured with 996 tones.
  • up to 37 STAs may be supported for DL / UL OFDMA transmission in an 80 MHz band.
  • up to 21 STAs may be supported for DL / UL OFDMA transmission in the 80 MHz band.
  • up to 13 STAs may be supported for DL / UL OFDMA transmission in the 80 MHz band.
  • up to five STAs may be supported for DL / UL OFDMA transmission in the 80 MHz band.
  • the resource unit when the resource unit is configured as shown in 16 (e), up to three STAs may be supported for DL / UL OFDMA transmission in the 80 MHz band. In addition, when a resource unit is configured as shown in 16 (f), the corresponding resource unit may be allocated to one STA for SU DL / UL transmission in the 80 MHz band.
  • the resource unit configuration scheme of FIG. 16 (a) to FIG. 16 (f) is applied based on the number of STAs participating in DL / UL OFDMA transmission and / or the amount of data transmitted or received by the STA, or the like. Alternatively, the resource unit configuration scheme in which FIGS. 16 (a) to 16 (f) are combined may be applied.
  • the bandwidth of the 160MHz PPDU may have a structure in which the 80MHz PPDU bandwidth described above in FIG. 32 is repeated twice.
  • resource units may be used for DL / UL OFDMA transmission among all resource units determined according to the above-described resource unit configuration. For example, when resource units are configured as shown in FIG. 16A within 20 MHz, one resource unit may be allocated to less than nine STAs, and the remaining resource units may not be allocated to any STAs.
  • the data field of the PPDU is multiplexed and transmitted in a frequency domain in units of resource units allocated to each STA.
  • the data field of the PPDU may be configured in units of resource units allocated to each STA and transmitted simultaneously to the AP.
  • the data field of a PPDU transmitted from each STA is multiplexed (or frequency multiplexed) in the frequency domain from the viewpoint of the AP.
  • one resource unit may consist of a plurality of streams in a spatial domain.
  • one or more streams may be allocated to one STA as DL / UL spatial resources, and different streams may be allocated to the plurality of STAs, respectively.
  • a resource unit composed of 106 tones in FIG. 16 (c) may consist of a plurality of streams in a spatial domain to simultaneously support DL / UL OFDMA and DL / UL MU-MIMO.
  • a resource unit composed of n tones will be referred to as an 'n tone resource unit' (n is a natural number).
  • n is a natural number
  • a resource unit consisting of 26 tones is referred to as a '26 ton resource unit '.
  • the FFT size may be 64, 128, 256, and 512 at 20 MHz, 40 MHz, 80 MHz, and 160 MHz, respectively.
  • an 802.11ax system ie, a HEW system
  • an FFT size ie, 4x
  • the FFT sizes used for legacy WLAN systems are 64, 128, 256, and 512 at 20 MHz, 40 MHz, 80 MHz, and 160 MHz, respectively
  • the FFT sizes used for the HE-part are 256, 512 at 20 MHz, 40 MHz, 80 MHz, and 160 MHz, respectively. , 1024, 2048.
  • the subcarrier spacing of the HE-part corresponds to one quarter of the legacy WLAN system, so that a nonzero value is mapped to 16 subcarrier spacings (for example, the subcarrier index is a multiple of 16).
  • the HE-STF sequence is defined, the HE-STF has the same period (ie 0.8 ms) as the legacy WLAN system. That is, if the legacy WLAN system is 1x, the HE-STF having the same period as that of the legacy WLAN system may be referred to as 1x HE-STF.
  • the HE-STF sequence is defined such that a non-zero value is mapped to eight subcarrier intervals (e.g., subcarrier index is a multiple of 8)
  • the HE-STF is twice as long as a legacy WLAN system. ) (Ie 1.6 ms).
  • the HE-STF at this time may be referred to as 2x HE-STF.
  • the HE-STF sequence is defined such that non-zero values are mapped to four subcarrier intervals (e.g., the subcarrier index is a multiple of four)
  • the HE-STF is four times larger than the legacy WLAN system. ) (Ie, 3.2 ⁇ s).
  • the HE-STF at this time may be referred to as 4x HE-STF.
  • the present invention can be applied to an 802.11ax system and proposes a (1x, 2x) HE-STF sequence having good performance in terms of peak-to-power average ratio (PAPR).
  • PAPR peak-to-power average ratio
  • PAPR is generally defined as the peak amplitude of an OFDM signal divided by the root mean square of the amplitude of the OFDM signal.
  • an OFDM signal consists of a combination of many subcarriers (or tones) each having a different amplitude
  • the PAPR value can be quite large.
  • High PAPR causes distortion of the signal and the like, and as a result, noise and interference between subcarriers may be increased due to signal distortion and the like.
  • low PAPR can prevent clipping of the signal. Therefore, it is effective to lower the PAPR of each OFDMA signal.
  • an M sequence that can be applied to an 802.11ax system and has a good performance in terms of PAPR, and propose a (1x, 2x) HE-STF sequence based on the M sequence.
  • new (1x, 2x) HE- optimized for 802.11ax systems by constructing (1x, 2x) HE-STF sequences based on M sequences and optimizing the coefficients and other extra values of the M sequences.
  • the phase rotation (or gamma value) of the 802.11ac system is applied and only the tone index is upscaled 4 times. That is, the (1x, 2x) HE-STF sequences proposed below are sequences before the phase rotation (or gamma value) is applied and have an optimized PAPR when the phase rotation (or gamma value) is applied.
  • the HE-STF sequence may be mapped in units of 16 tones or 8 tones to the (data) tones included in the channel.
  • the HE-STF sequence may be configured with a value '0' or a value other than '0' (coefficient).
  • the (data) tone to which the HE-STF sequence is mapped will be referred to as a '(1x, 2x) HE-STF tone (or subcarrier)'.
  • the HE-STF tone in the PPDU transmission for each channel (20MHz / 40MHz / 80MHz) will be described.
  • FIG. 17 illustrates a 1x HE-STF tone in channel-specific PPDU transmission according to an embodiment of the present invention. More specifically, FIG. 17 illustrates a HE-STF tone (i.e. 16 tone sampling) with a 0.8 ms period in a 20 MHz / 40 MHz / 80 MHz bandwidth. Therefore, in FIG. 17, HE-STF tones for each bandwidth (or channel) may be located at 16 tone intervals.
  • the x axis represents a frequency domain.
  • the number on the x-axis represents the index of the tone, and the arrow indicates the non-zero mapping to that tone index.
  • FIG. 17 (a) is a diagram illustrating a 1x HE-STF tone in a 20 MHz PPDU transmission.
  • the 1x HE-STF sequence is a tone index from -112 to 112.
  • the 1x HE-STF tone in the 20 MHz channel may be located at a tone index that is a multiple of 16 of the tones having a tone index from -112 to 112. Therefore, a total of 15 1x HE-STF tones to which a 1x HE-STF sequence is mapped may exist in a 20MHz channel.
  • 17 (b) is a diagram illustrating 1 ⁇ HE-STF tones in a 40 MHz PPDU transmission.
  • the 1x HE-STF sequence is a tone index from -240 to 240.
  • the tones having a tone mapped to a tone having a tone index that is a multiple of 16 0 may be mapped to the remaining tones. That is, the 1x HE-STF tone in the 40 MHz channel may be located at a tone index that is a multiple of 16 of the tones having a tone index from -240 to 240. Therefore, there may be a total of 31 1x HE-STF tones to which the 1x HE-STF sequence is mapped in the 40MHz channel.
  • 17 (c) is a diagram illustrating a 1x HE-STF tone in an 80 MHz PPDU transmission.
  • the 1x HE-STF sequence is a tone index from -496 to 496.
  • the tones having a tone mapped to a tone having a tone index that is a multiple of 16 0 may be mapped to the remaining tones. That is, the 1x HE-STF tone in the 80 MHz channel may be located at a tone index that is a multiple of 16 of the tones having tone indexes from -496 to 496. Therefore, a total of 63 1x HE-STF tones to which a 1x HE-STF sequence is mapped may exist in an 80 MHz channel.
  • FIG. 18 is a diagram illustrating a 2x HE-STF tone in channel-specific PPDU transmission according to an embodiment of the present invention. More specifically, FIG. 18 illustrates a HE-STF tone (i.e. 8 tone sampling) with a 1.6 ms period in a 20 MHz / 40 MHz / 80 MHz bandwidth. Therefore, in FIG. 18, HE-STF tones for each bandwidth (or channel) may be located at eight tone intervals.
  • HE-STF tone i.e. 8 tone sampling
  • the x axis represents a frequency domain.
  • the number on the x-axis represents the index of the tone, and the arrow indicates the non-zero mapping to that tone index.
  • 18 (a) is a diagram illustrating a 2x HE-STF tone in a 20 MHz PPDU transmission.
  • the 2x HE-STF sequence when a HE-STF sequence for a 1.6 ms period (ie, a 2x HE-STF sequence) is mapped to tones of a 20 MHz channel, the 2x HE-STF sequence has a tone index from -120 to 120.
  • the tones having a tone mapped to a tone having a tone index that is a multiple of 8 0 may be mapped to the remaining tones. That is, the 2x HE-STF tone in the 20 MHz channel may be located at a tone index that is a multiple of 8 of the tones having a tone index from -120 to 120. Therefore, a total of 31 2x HE-STF tones to which a 2x HE-STF sequence is mapped may exist in a 20MHz channel.
  • 18 (b) is a diagram illustrating a 2 ⁇ HE-STF tone in a 40 MHz PPDU transmission.
  • the 2x HE-STF sequence when a HE-STF sequence for a 1.6 ms period (i.e., a 2x HE-STF sequence) is mapped to tones of a 40 MHz channel, the 2x HE-STF sequence has a tone index from -248 to 248.
  • the tones having a tone mapped to a tone having a tone index that is a multiple of 8 0 may be mapped to the remaining tones. That is, the 2x HE-STF tone in the 40 MHz channel may be located at a tone index that is a multiple of 8 of the tones having a tone index from -248 to 248.
  • tones having a tone index ⁇ 248 correspond to guard tones (left and right guard tones), and tones having a tone index 0 may be nulled corresponding to DC tones ( That is, it may have a value of zero). Accordingly, there may be a total of 60 2x HE-STF tones to which a 2x HE-STF sequence is mapped in a 40MHz channel.
  • 18 (c) is a diagram illustrating a 2x HE-STF tone in an 80 MHz PPDU transmission.
  • the 2x HE-STF sequence when a HE-STF sequence for a 1.6 ms period (i.e., a 2x HE-STF sequence) is mapped to tones of an 80 MHz channel, the 2x HE-STF sequence has a tone index from -504 to 504.
  • the tones having a tone mapped to a tone having a tone index that is a multiple of 8 0 may be mapped to the remaining tones. That is, the 2x HE-STF tone in the 80 MHz channel may be located at a tone index that is a multiple of 8 of the tones having a tone index from -504 to 504.
  • tones having a tone index ⁇ 504 correspond to guard tones (left and light guard tones), and a tone having a tone index 0 may be nulled (ie, may have a value of 0) corresponding to a DC tone.
  • a total of 124 2x HE-STF tones to which a 2x HE-STF sequence is mapped may exist in an 80 MHz channel.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as in Equation 1.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as in Equation 1 may be determined as in Equation 2 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a zero value.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • a 1x HE-STF sequence may be defined so that the value '0' is mapped to the tone HES_-112,112 (0) located at the tone index '0'. That is, the tone located in the tone index '0' corresponds to the DC tone and may be nulled.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • FIG. 1 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the second M sequence.
  • a 1x HE-STF sequence in a 40 MHz channel may be defined such that M sequences, 0 and jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • tone index -240 to -16 have M sequences
  • -JXM sequences can be mapped to 15 tones located in 16-ton increments from tone index 16 to 240.
  • HE-STF tones that do not have a zero value can be placed in 16 tone intervals on a 40 MHz channel (but 32 tone intervals for tones located at tone indices -16 and 16), with 1 having a value of 0.
  • HE-STF tones may be located at tone index 0.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the second M sequence
  • -j is multiplied by the third M sequence.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • the 1x HE-STF sequence on the 80 MHz channel is in 16-tone increments from tone index -496 to 496.
  • M sequences may be defined to be sequentially mapped.
  • the tone at tone index -256 has a value of ( ⁇ 1 / 2) (1 + j),
  • -Tone at tone index 256 has a value of ( ⁇ 1 / 2) (-1-j),
  • M sequences can be mapped to 15 tones located in 16-tone units from tone indexes 272 to 496.
  • the tone at tone index -256 has a value of ( ⁇ 1 / 2) (-1-j),
  • the tone at tone index 256 has a value of ( ⁇ 1 / 2) (1 + j),
  • M sequences can be mapped to 15 tones located in 16-tone units from tone indexes 272 to 496.
  • 62 HE-STF tones with no zero value can be placed in 16 tone intervals on an 80 MHz channel (but 32 tone intervals for tones located at tone indices -16 and 16), with 1 having a value of 0 HE-STF tones may be located at tone index 0.
  • the HE-STF sequence for a period of 1.6 ms it may be configured based on the M sequence defined in Equation 1, and more specifically, may be determined as in Equation 3.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • the second M sequence is multiplied by -1. Therefore, a 2x HE-STF sequence in a 20 MHz channel is defined so that M sequences, 0 and -1XM sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • the -1 ⁇ M sequence can be mapped to 15 tones located in 8-ton increments from tone index 8 to 120.
  • 30 HE-STF tones with zero values can be placed in eight tone intervals on a 20 MHz channel (but 16 tone intervals for tones located at tone indices -8 and 8), with a zero value of 1 HE-STF tones may be located at tone index 0.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • the second M sequence is -1
  • the third and fourth M sequences are respectively multiplied by -j.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j), and b may be ( ⁇ 1 / 2) (-1 + j).
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence in 8-tone increments (HES_-248,248 (-248: 8: 248)) from tone index -248 to 248, ( ⁇ 1 / 2) (-1-j ), -1XM sequences, 0, -jXM sequences, ( ⁇ 1 / 2) (-1 + j), and -jXM sequences may be defined to be sequentially mapped.
  • the tone at tone index -128 has a value of ( ⁇ 1 / 2) (-1-j),
  • the -jXM sequence can be mapped to 15 tones located in 8 tones in tone indexes 136 to 248.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to the tones HES_248 and 248 ( ⁇ 248) respectively located at the tone indexes -248 and 248. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones with zero values in a 40 MHz channel can be located at eight tone intervals (16 tone intervals for tones located at tone indices -8 and 8), and 3 with zero values.
  • HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • the 2x HE-STF sequence is ⁇ M sequence, a, M sequence, b, M sequence, c, M sequence, 0, M sequence, d, M sequence, e, M sequence, f, M sequence ⁇ It can be configured as.
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -1 is multiplied by the fourth and sixth M sequences, respectively.
  • a to f represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (-1-j)
  • b is ( ⁇ 1 / 2) (1 + j)
  • c is ( ⁇ 1 / 2) (1 + j)
  • d is ( ⁇ 1 / 2) (-1-j)
  • e may be ( ⁇ 1 / 2) (-1-j)
  • f may be ( ⁇ 1 / 2) (-1-j).
  • a 2x HE-STF sequence on an 80 MHz channel is an M sequence with tone indexes -504 to 504 in 8-tone increments (HES_-504,504 (-504: 8: 504)), ( ⁇ 1 / 2) (-1-j) , M sequence, ( ⁇ 1 / 2) (1 + j), M sequence, ( ⁇ 1 / 2) (1 + j), M sequence, 0, M sequence, ( ⁇ 1 / 2) (-1-j ), M sequence, ( ⁇ 1 / 2) (-1-j), M sequence, ( ⁇ 1 / 2) (-1-j), M sequence, ( ⁇ 1 / 2) (-1-j), and M sequence may be defined to be mapped sequentially.
  • the tone at tone index -384 has a value of ( ⁇ 1 / 2) (-1-j),
  • the tone at tone index -256 has a value of ( ⁇ 1 / 2) (1 + j),
  • the tone at tone index -128 has a value of ( ⁇ 1 / 2) (1 + j),
  • the tone at tone index 128 has the value ( ⁇ 1 / 2) (-1-j),
  • -Tone at tone index 256 has a value of ( ⁇ 1 / 2) (-1-j),
  • the tone at tone index 384 has a value of ( ⁇ 1 / 2) (-1-j),
  • M sequences may be mapped to 15 tones located in 8-tone units from tone indexes 392 to 504.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to tones HES_504 and 504 ( ⁇ 504) respectively located at tone indices -504 and 504. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value can be located in eight tone intervals on an 80 MHz channel (but 16 tone intervals for tones located at tone indices -8 and 8), with a zero value of 3 HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 4.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as shown in Equation 4 may be determined as shown in Equation 5 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a zero value.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' corresponds to the DC tone and may be nulled.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second M sequence. Therefore, the 1x HE-STF sequence in the 40 MHz channel is defined so that the M sequence, 0 and -jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second and third M sequences
  • -1 is multiplied by the fourth M sequence.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j), and b may be ( ⁇ 1 / 2) (-1 + j).
  • the 1x HE-STF sequence is an M sequence with tone indexes -496 to 496 in 16-tone increments (HES_-496,496 (-496: 16: 496)), ( ⁇ 1 / 2) (-1-j) , -jXM sequences, 0, -jXM sequences, ( ⁇ 1 / 2) (-1 + j), and -1XM sequences may be defined to be sequentially mapped.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • Equation 6 Even in the case of a HE-STF sequence for a period of 1.6 ms, it may be configured based on the M sequence defined in Equation 4, and more specifically, may be determined as in Equation 6.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ . Therefore, a 2x HE-STF sequence in a 20 MHz channel may be defined such that M sequences, 0, and M sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the third and fourth M sequences, respectively.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (1 + j), and b may be ( ⁇ 1 / 2) (-1 + j).
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence in 8-tone increments (HES_-248,248 (-248: 8: 248)) from tone index -248 to 248, ( ⁇ 1 / 2) (1 + j) , M sequence, 0, j X M sequence, ( ⁇ 1 / 2) (-1 + j), j X M sequence can be defined to be mapped sequentially.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to the tones HES_248 and 248 ( ⁇ 248) respectively located at the tone indexes -248 and 248. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones in the 40 MHz channel can be located at 8 tone intervals (with 16 tone intervals for tones located at tone indexes -8 and 8), with 0 values.
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • the 2x HE-STF sequence is ⁇ M sequence, a, M sequence, b, M sequence, c, M sequence, 0, M sequence, d, M sequence, e, M sequence, f, M sequence ⁇ It can be configured as.
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the third and sixth M sequences
  • -j is multiplied by the fourth and fifth M sequences
  • -1 is multiplied by the seventh and eighth M sequences, respectively.
  • a to f represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (-1 + j)
  • b is ( ⁇ 1 / 2) (1 + j)
  • c is ( ⁇ 1 / 2) (1 + j)
  • d is ( ⁇ 1 / 2) (1 + j)
  • e may be ( ⁇ 1 / 2) (1 + j)
  • f may be ( ⁇ 1 / 2) (1-j).
  • a 2x HE-STF sequence on an 80 MHz channel is an M sequence with tone indexes -504 to 504 in 8-tone increments (HES_-504,504 (-504: 8: 504)), ( ⁇ 1 / 2) (-1 + j) , M sequence, ( ⁇ 1 / 2) (1 + j), jXM sequence, ( ⁇ 1 / 2) (1 + j), -jXM sequence, 0, -jXM sequence, ( ⁇ 1 / 2) (1+ j), jXM sequences, ( ⁇ 1 / 2) (1 + j), ⁇ 1XM sequences, ( ⁇ 1 / 2) (1-j), and ⁇ 1XM sequences may be defined to be mapped sequentially.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to tones HES_504 and 504 ( ⁇ 504) respectively located at tone indices -504 and 504. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 7.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as shown in Equation 7 may be determined as shown in Equation 8 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a zero value.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' may be nulled because it is a DC tone.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second M sequence. Therefore, the 1x HE-STF sequence in the 40 MHz channel is defined so that the M sequence, 0 and -jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, M sequence, a, 0, b, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -1 is multiplied by the second and third M sequences.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j), and b may be ( ⁇ 1 / 2) (-1-j).
  • the 1x HE-STF sequence is the M sequence, -1XM sequence, ( ⁇ 1 / 2) (-) in 16-tone increments (HES_-496,496 (-496: 16: 496)) from tone index -496 to 496.
  • 1-j 0, ( ⁇ 1 / 2) (-1-j), -1XM sequence, and M sequence may be defined to be sequentially mapped.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the HE-STF sequence for a period of 1.6 ms it may be configured based on the M sequence defined in Equation 7, and more specifically, may be determined as in Equation 9.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ . Therefore, a 2x HE-STF sequence in a 20 MHz channel may be defined such that M sequences, 0, and M sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, M sequence, 0, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second and fourth M sequences, respectively, and -1 is multiplied by the third M sequence.
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence, -jXM sequence, 0, -1XM sequence in tone tones (HES_-248,248 (-248: 8: 248)) in tone index above -248 and below 248.
  • -jXM sequences may be defined to be sequentially mapped, and tones (HES_-248, 248 ( ⁇ 248)) located at tone indices -248 and 248, respectively, may be defined such that zero values are mapped. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones in the 40 MHz channel can be located at 8 tone intervals (with 16 tone intervals for tones located at tone indexes -8 and 8), with 0 values.
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • a 2x HE-STF sequence may consist of ⁇ M sequence, M sequence, M sequence, M sequence, a, b, 0, c, d, M sequence, M sequence, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the second and eighth M sequences
  • -j is multiplied by the fourth and sixth M sequences
  • -1 is multiplied by the fifth and seventh M sequences, respectively.
  • a to d represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (1 + j)
  • b is ( ⁇ 1 / 2) (1 + j)
  • c is ( ⁇ 1 / 2) (1-j)
  • d is ( ⁇ 1/2) (-1 + j).
  • a 2x HE-STF sequence on an 80 MHz channel has M sequences, jXM sequences, M sequences, -jXM sequences, with tone indices greater than -504 and less than 504 in 8-tone increments (HES_-504,504 (-504: 8: 504)).
  • ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1 + j), 0, ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1 + j) , -1XM sequences, -jXM sequences, -1XM sequences, and jXM sequences can be defined to be mapped sequentially, with zero values mapped to tones (HES_-504,504 ( ⁇ 504)) located at tone indices -504 and 504, respectively. It can be defined to be. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 10.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as shown in Equation 10 may be determined as shown in Equation 5 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a value of zero.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' may be nulled because it is a DC tone.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the second M sequence.
  • a 1x HE-STF sequence in a 40 MHz channel may be defined such that M sequences, 0 and jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second M sequence
  • j is multiplied by the third M sequence.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (1 + j), and b may be ( ⁇ 1 / 2) (-1-j).
  • a 1x HE-STF sequence on an 80 MHz channel is an M sequence with tone indexes -496 to 496 in 16-tone increments (HES_-496,496 (-496: 16: 496)), ( ⁇ 1 / 2) (1 + j),
  • the -jXM sequence, 0, jXM sequence, ( ⁇ 1 / 2) (-1-j) and M sequence may be defined to be sequentially mapped.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the HE-STF sequence for a period of 1.6 ms it may be configured based on the M sequence defined in Equation 10, and more specifically, may be determined as in Equation 12.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • the second M sequence is multiplied by -1. Therefore, a 2x HE-STF sequence in a 20 MHz channel is defined so that M sequences, 0 and -1XM sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the third M sequence
  • j is multiplied by the fourth M sequence.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j), and b may be ( ⁇ 1 / 2) (-1-j).
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence in 8-tone increments (HES_-248,248 (-248: 8: 248)) from tone index -248 to 248, ( ⁇ 1 / 2) (-1-j ), M sequence, 0, -jXM sequence, ( ⁇ 1 / 2) (-1-j), jXM sequence may be defined to be sequentially mapped.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to the tones HES_248 and 248 ( ⁇ 248) respectively located at the tone indexes -248 and 248. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones in the 40 MHz channel can be located at 8 tone intervals (with 16 tone intervals for tones located at tone indexes -8 and 8), with 0 values.
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • the 2x HE-STF sequence is ⁇ M sequence, a, M sequence, b, M sequence, c, M sequence, 0, M sequence, d, M sequence, e, M sequence, f, M sequence ⁇ It can be configured as.
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the third and fifth M sequences
  • j is multiplied by the fourth and sixth M sequences, respectively.
  • a to f represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (-1-j)
  • b is ( ⁇ 1 / 2) (-1-j)
  • c is ( ⁇ 1 / 2) (-1-j)
  • d May be ( ⁇ 1 / 2) (1 + j)
  • e may be ( ⁇ 1 / 2) (1 + j)
  • f may be ( ⁇ 1 / 2) (-1-j).
  • a 2x HE-STF sequence on an 80 MHz channel is an M sequence with tone indexes -504 to 504 in 8-tone increments (HES_-504,504 (-504: 8: 504)), ( ⁇ 1 / 2) (-1-j) , M sequence, ( ⁇ 1 / 2) (-1-j), -jXM sequence, ( ⁇ 1 / 2) (-1-j), jXM sequence, 0, -jXM sequence, ( ⁇ 1 / 2) ( 1 + j), jXM sequence, ( ⁇ 1 / 2) (1 + j), M sequence, ( ⁇ 1 / 2) (-1-j), and M sequence may be defined to be sequentially mapped.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to tones HES_504 and 504 ( ⁇ 504) respectively located at tone indices -504 and 504. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 13.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as shown in Equation 13 may be determined as shown in Equation 14 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a zero value.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' may be nulled because it is a DC tone.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the second M sequence.
  • a 1x HE-STF sequence in a 40 MHz channel may be defined such that M sequences, 0 and jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, M sequence, a, 0, b, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -1 is multiplied by the third and fourth M sequences.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j), and b may be ( ⁇ 1 / 2) (1 + j).
  • the 1x HE-STF sequence is the M sequence, M sequence, ( ⁇ 1 / 2) (-1 in 16-tone increments (HES_-496,496 (-496: 16: 496)) from tone index -496 to 496.
  • -j 0, ( ⁇ 1 / 2) (1 + j), -1XM sequence, and -1XM sequence may be defined to be sequentially mapped.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the HE-STF sequence for a period of 1.6 ms it may be configured based on the M sequence defined in Equation 7, and more specifically, may be determined as in Equation 15.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • the second M sequence is multiplied by -1. Therefore, a 2x HE-STF sequence in a 20 MHz channel is defined so that M sequences, 0 and -1XM sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, M sequence, 0, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the third M sequence
  • -j is multiplied by the fourth M sequence.
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence, M sequence, 0, jXM sequence, in 8-tone units (HES_-248,248 (-248: 8: 248)) above tone index -248 and below 248.
  • the j X M sequences may be defined to be mapped sequentially, and 0 may be defined to be mapped to tones HES_-248 and 248 ( ⁇ 248) located at tone indices -248 and 248, respectively. That is, the tones located at the tone index ⁇ 248 correspond to the guard tones (left / light guard tones) and thus can be nulled. As a result, 60 HE-STF tones with zero values in the 40 MHz channel have 8 tone intervals. 3 HE-STF tones having a value of 0 may be located at tone indices 0 and ⁇ 248, respectively (16 tones apart for tones located at tone indices -8 and 8).
  • a 2x HE-STF sequence may consist of ⁇ M sequence, M sequence, M sequence, M sequence, a, b, 0, c, d, M sequence, M sequence, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • the second and sixth M sequences are each multiplied by -1.
  • a to d represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (-1-j)
  • b is ( ⁇ 1 / 2) (-1-j)
  • c is ( ⁇ 1 / 2) (1 + j)
  • d is ( ⁇ 1 / 2) (-1-j).
  • a 2x HE-STF sequence on an 80 MHz channel is an M sequence, a -1 ⁇ M sequence, an M sequence, an M sequence, in 8-tone increments (HES_-504,504 (-504: 8: 504)) at tone indices above -504 and below 504.
  • M sequence, -1XM sequence, M sequence, and M sequence can be defined to be mapped sequentially, with zero values mapped to tones (HES_-504,504 ( ⁇ 504)) located at tone indices -504 and 504, respectively. It can be defined to be. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 16.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as shown in Equation 16 may be determined as shown in Equation 17 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a zero value.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' may be nulled because it is a DC tone.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second M sequence. Therefore, the 1x HE-STF sequence in the 40 MHz channel is defined so that the M sequence, 0 and -jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the second and third M sequences
  • -1 is multiplied by the fourth M sequence.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (1 + j), and b may be ( ⁇ 1 / 2) (-1 + j).
  • a 1x HE-STF sequence on an 80 MHz channel is an M sequence with tone indexes -496 to 496 in 16-tone increments (HES_-496,496 (-496: 16: 496)), ( ⁇ 1 / 2) (1 + j), jXM sequence, 0, jXM sequence, ( ⁇ 1 / 2) (-1 + j) and -1XM sequence can be defined to be mapped sequentially.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the HE-STF sequence for a period of 1.6 ms it may be configured based on the M sequence defined in Equation 16, and more specifically, may be determined as in Equation 18.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ . Therefore, a 2x HE-STF sequence in a 20 MHz channel may be defined such that M sequences, 0, and M sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the third and fourth M sequences.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j), and b may be ( ⁇ 1 / 2) (1-j).
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence in 8-tone increments (HES_-248,248 (-248: 8: 248)) from tone index -248 to 248, ( ⁇ 1 / 2) (-1-j ), M sequence, 0, j X M sequence, ( ⁇ 1 / 2) (1-j), j X M sequence can be defined to be sequentially mapped.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to the tones HES_248 and 248 ( ⁇ 248) respectively located at the tone indexes -248 and 248. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones in the 40 MHz channel can be located at 8 tone intervals (with 16 tone intervals for tones located at tone indexes -8 and 8), with 0 values.
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • the 2x HE-STF sequence is ⁇ M sequence, a, M sequence, b, M sequence, c, M sequence, 0, M sequence, d, M sequence, e, M sequence, f, M sequence ⁇ It can be configured as.
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the third and sixth M sequences, j by the fourth and fifth M sequences, and -1 by the seventh and eighth M sequences, respectively.
  • a to f represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (-1 + j)
  • b is ( ⁇ 1 / 2) (-1-j)
  • c is ( ⁇ 1 / 2) (-1-j)
  • e may be ( ⁇ 1 / 2) (-1-j)
  • f may be ( ⁇ 1 / 2) (1-j).
  • a 2x HE-STF sequence on an 80 MHz channel is an M sequence with tone indexes -504 to 504 in 8-tone increments (HES_-504,504 (-504: 8: 504)), ( ⁇ 1 / 2) (-1 + j) , M sequence, ( ⁇ 1 / 2) (-1-j), -jXM sequence, ( ⁇ 1 / 2) (-1-j), jXM sequence, 0, jXM sequence, ( ⁇ 1 / 2) (- 1-j), -jXM sequences, ( ⁇ 1 / 2) (-1-j), -1XM sequences, ( ⁇ 1 / 2) (1-j), and -1XM sequences may be defined to be mapped sequentially. have.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to tones HES_504 and 504 ( ⁇ 504) respectively located at tone indices -504 and 504. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 19.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as shown in Equation 19 may be determined as shown in Equation 20 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a zero value.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' may be nulled because it is a DC tone.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second M sequence. Therefore, the 1x HE-STF sequence in the 40 MHz channel is defined so that the M sequence, 0 and -jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, M sequence, a, 0, b, M sequence, M sequence ⁇ .
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j)
  • b may be ( ⁇ 1 / 2) (-1-j).
  • the 1x HE-STF sequence is the M sequence, M sequence, ( ⁇ 1 / 2) (-1 in 16-tone increments (HES_-496,496 (-496: 16: 496)) from tone index -496 to 496. -j), 0, ( ⁇ 1 ⁇ 2) (-1-j), M sequence, and M sequence may be defined to be mapped sequentially.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the HE-STF sequence for a period of 1.6 ms it may be configured based on the M sequence defined in Equation 19, and more specifically, may be determined as Equation 21.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ . Therefore, a 2x HE-STF sequence in a 20 MHz channel may be defined such that M sequences, 0, and M sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, M sequence, 0, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second and fourth M sequences
  • -1 is multiplied by the third M sequence.
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence, -jXM sequence, 0, -1XM sequence in tone tones (HES_-248,248 (-248: 8: 248)) in tone index above -248 and below 248.
  • -jXM sequences may be defined to be sequentially mapped, and tones (HES_-248, 248 ( ⁇ 248)) located at tone indices -248 and 248, respectively, may be defined such that zero values are mapped. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones in the 40 MHz channel can be located at 8 tone intervals (with 16 tone intervals for tones located at tone indexes -8 and 8), with 0 values.
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • a 2x HE-STF sequence may consist of ⁇ M sequence, M sequence, M sequence, M sequence, a, b, 0, c, d, M sequence, M sequence, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second and sixth M sequences, respectively, and j is multiplied by the fourth and eighth M sequences, respectively.
  • a to d represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (1 + j)
  • b is ( ⁇ 1 / 2) (-1-j)
  • c is ( ⁇ 1 / 2) (-1 + j)
  • d is ( ⁇ 1 / 2) (-1 + j).
  • a 2x HE-STF sequence on an 80 MHz channel is an M sequence, -jXM sequence, M sequence, jXM sequence, in 8-tone increments (HES_-504,504 (-504: 8: 504)) above tone index -504 and below 504.
  • M sequences, -jXM sequences, M sequences, and jXM sequences can be defined to be mapped sequentially, with zero values mapped to tones (HES_-504,504 ( ⁇ 504)) located at tone indices -504 and 504, respectively. It can be defined to be. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 22.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as shown in Equation 22 may be determined as shown in Equation 23 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a zero value.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' may be nulled because it is a DC tone.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second M sequence. Therefore, the 1x HE-STF sequence in the 40 MHz channel is defined so that the M sequence, 0 and -jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j)
  • b may be ( ⁇ 1 / 2) (-1-j).
  • the 1x HE-STF sequence is an M sequence with tone indexes -496 to 496 in 16-tone increments (HES_-496,496 (-496: 16: 496)), ( ⁇ 1 / 2) (-1-j) , M sequences, 0, M sequences, ( ⁇ 1 / 2) (-1-j) and M sequences may be defined to be sequentially mapped.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the HE-STF sequence for a period of 1.6 ms it may be configured based on the M sequence defined in Equation 22, and more specifically, may be determined as in Equation 24.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ . Therefore, a 2x HE-STF sequence in a 20 MHz channel may be defined such that M sequences, 0, and M sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • the second M sequence is multiplied by -1
  • the third and fourth M sequences are multiplied by j.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (1 + j), and b may be ( ⁇ 1 / 2) (-1 + j).
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence in 8-tone increments (HES_-248,248 (-248: 8: 248)) from tone index -248 to 248, ( ⁇ 1 / 2) (1 + j) , -1XM sequence, 0, jXM sequence, ( ⁇ 1 / 2) (-1 + j), jXM sequence may be defined to be sequentially mapped.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to the tones HES_248 and 248 ( ⁇ 248) respectively located at the tone indexes -248 and 248. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones in the 40 MHz channel can be located at 8 tone intervals (with 16 tone intervals for tones located at tone indexes -8 and 8), with 0 values.
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • the 2x HE-STF sequence is ⁇ M sequence, a, M sequence, b, M sequence, c, M sequence, 0, M sequence, d, M sequence, e, M sequence, f, M sequence ⁇ It can be configured as.
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • the second and seventh M sequences are each multiplied by -1.
  • a to f represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (1 + j)
  • b is ( ⁇ 1 / 2) (-1-j)
  • c is ( ⁇ 1 / 2) (1 + j)
  • d is ( ⁇ 1 / 2) (-1-j)
  • e may be ( ⁇ 1 / 2) (1 + j)
  • f may be ( ⁇ 1 / 2) (-1-j).
  • a 2x HE-STF sequence on an 80 MHz channel is an M sequence with tone indexes -504 to 504 in 8-tone increments (HES_-504,504 (-504: 8: 504)), ( ⁇ 1 / 2) (1 + j), -1XM sequence, ( ⁇ 1 / 2) (-1-j), M sequence, ( ⁇ 1 / 2) (1 + j), M sequence, 0, M sequence, ( ⁇ 1 / 2) (-1- j), M sequence, ( ⁇ 1 / 2) (1 + j), ⁇ 1XM sequence, ( ⁇ 1 / 2) (-1-j), and M sequence may be defined to be sequentially mapped.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to tones HES_504 and 504 ( ⁇ 504) respectively located at tone indices -504 and 504. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 25.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as shown in Equation 25 may be determined as shown in Equation 26 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a zero value.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' may be nulled because it is a DC tone.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second M sequence. Therefore, the 1x HE-STF sequence in the 40 MHz channel is defined so that the M sequence, 0 and -jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, M sequence, a, 0, b, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -1 is multiplied by the third and fourth M sequences.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j), and b may be ( ⁇ 1 / 2) (1 + j).
  • the 1x HE-STF sequence is the M sequence, M sequence, ( ⁇ 1 / 2) (-1 in 16-tone increments (HES_-496,496 (-496: 16: 496)) from tone index -496 to 496.
  • -j 0, ( ⁇ 1 / 2) (1 + j), -1XM sequence, and -1XM sequence may be defined to be sequentially mapped.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the HE-STF sequence for a period of 1.6 ms it may be configured based on the M sequence defined in Equation 25, and more specifically, may be determined as in Equation 27.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ . Therefore, a 2x HE-STF sequence in a 20 MHz channel may be defined such that M sequences, 0, and M sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, M sequence, 0, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the third M sequence
  • j is multiplied by the fourth M sequence.
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence, M sequence, 0, -jXM sequence, in 8-tone increments (HES_-248,248 (-248: 8: 248)) above tone index -248 and below 248.
  • the j X M sequences may be defined to be mapped sequentially, and 0 may be defined to be mapped to tones HES_-248 and 248 ( ⁇ 248) located at tone indices -248 and 248, respectively. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones in the 40 MHz channel can be located at 8 tone intervals (with 16 tone intervals for tones located at tone indexes -8 and 8), with 0 values.
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • a 2x HE-STF sequence may consist of ⁇ M sequence, M sequence, M sequence, M sequence, a, b, 0, c, d, M sequence, M sequence, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -1 is multiplied by the third, fifth, seventh, and eighth M sequences, respectively.
  • a to d represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (-1-j)
  • b is ( ⁇ 1 / 2) (-1-j)
  • c is ( ⁇ 1 / 2) (-1-j)
  • d May be ( ⁇ 1 / 2) (-1-j).
  • a 2x HE-STF sequence on an 80 MHz channel is M sequence, M sequence, -1XM sequence, M sequence, with tone index above -504 and below 504 in 8 tone units (HES_-504,504 (-504: 8: 504)).
  • ( ⁇ 1 / 2) (-1-j), ( ⁇ 1 / 2) (-1-j), 0, ( ⁇ 1 / 2) (-1-j), ( ⁇ 1 / 2) (-1 -j), -1XM sequence, M sequence, -1XM sequence, and -1XM sequence can be defined to be mapped sequentially, with tones (HES_-504,504 ( ⁇ 504)) located at tone indices -504 and 504 respectively. Values can be defined to map. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 28.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz based on the M sequence configured as shown in Equation 28 may be determined as shown in Equation 29 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a zero value.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' may be nulled because it is a DC tone.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the second M sequence.
  • a 1x HE-STF sequence in a 40 MHz channel may be defined such that M sequences, 0 and jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the second M sequence
  • j is multiplied by the third M sequence.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (-1-j), and b may be ( ⁇ 1 / 2) (1 + j).
  • the 1x HE-STF sequence is an M sequence with tone indexes -496 to 496 in 16-tone increments (HES_-496,496 (-496: 16: 496)), ( ⁇ 1 / 2) (-1-j) , -jXM sequences, 0, jXM sequences, ( ⁇ 1 / 2) (1 + j), and M sequences may be defined to be sequentially mapped.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the HE-STF sequence for the period of 1.6 ms it may be configured based on the M sequence defined in Equation 28, and more specifically, may be determined as in Equation 30.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • the second M sequence is multiplied by -1. Therefore, a 2x HE-STF sequence in a 20 MHz channel is defined so that M sequences, 0 and -1XM sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, a, M sequence, 0, M sequence, b, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the third M sequence
  • j is multiplied by the fourth M sequence.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (1 + j), and b may be ( ⁇ 1 / 2) (1 + j).
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence in 8-tone increments (HES_-248,248 (-248: 8: 248)) from tone index -248 to 248, ( ⁇ 1 / 2) (1 + j) , M sequences, 0, -jXM sequences, ( ⁇ 1 / 2) (1 + j), jXM sequences may be defined to be sequentially mapped.
  • a 2x HE-STF sequence may be defined such that zero values are mapped to the tones HES_248 and 248 ( ⁇ 248) respectively located at the tone indexes -248 and 248. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones in the 40 MHz channel can be located at 8 tone intervals (with 16 tone intervals for tones located at tone indexes -8 and 8), with 0 values.
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • the 2x HE-STF sequence is ⁇ M sequence, a, M sequence, b, M sequence, c, M sequence, 0, M sequence, d, M sequence, e, M sequence, f, M sequence ⁇ It can be configured as.
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -j is multiplied by the third and fifth M sequences, respectively, and j is multiplied by the fourth and sixth M sequences, respectively.
  • a to f represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (1 + j)
  • b is ( ⁇ 1 / 2) (1 + j)
  • c is ( ⁇ 1 / 2) (1 + j)
  • d is ( ⁇ 1/2) (-1-j)
  • e may be ( ⁇ 1 / 2) (-1-j)
  • f may be ( ⁇ 1 / 2) (1 + j).
  • a 2x HE-STF sequence on an 80 MHz channel is an M sequence with tone indexes -504 to 504 in 8-tone increments (HES_-504,504 (-504: 8: 504)), ( ⁇ 1 / 2) (1 + j), M sequence, ( ⁇ 1 / 2) (1 + j), -jXM sequence, ( ⁇ 1 / 2) (1 + j), jXM sequence, 0, -jXM sequence, ( ⁇ 1 / 2) (-1- j), jXM sequence, ( ⁇ 1 / 2) (-1-j), M sequence, ( ⁇ 1 / 2) (1 + j), and M sequence may be defined to be sequentially mapped.
  • the 2x HE-STF sequence may be defined such that zero values are mapped to the tones HES_-248 and 248 ( ⁇ 248) respectively located at the tone indexes -504 and 504. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • the 1x HE-STF sequence for each channel may be generated based on the M sequence.
  • the M sequence may be determined as shown in Equation 31.
  • the 1x HE-STF sequence at 20 MHz, 40 MHz, and 80 MHz may be determined as shown in Equation 32 below.
  • the 1x HE-STF sequence may be composed of an M sequence and a value of zero.
  • the 1x HE-STF sequence in the 20 MHz channel may be defined such that the M sequence is mapped in 16 tone units (HES_-112, 112 (-112: 16: 112)) from tone index -112 to 112.
  • the 1x HE-STF sequence may be defined such that a value of '0' is mapped to a tone (HES_-112,112 (0)) located at the tone index '0'. That is, the tone located in the tone index '0' may be nulled because it is a DC tone.
  • tone indexes -112, -96, -80,... M sequences are sequentially mapped to 15 tones located at, 80, 96, and 112, but a 0 value may be mapped to a tone located at tone index 0.
  • 14 HE-STF tones on the 20 MHz channel can be located at 16 tone intervals (but 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may consist of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the second M sequence.
  • a 1x HE-STF sequence in a 40 MHz channel may be defined such that M sequences, 0 and jXM sequences are sequentially mapped in 16 tone units (HES_-240,240 (-240: 16: 240)) from tone index -240 to 240. Can be.
  • 30 HE-STF tones with zero values in the 40 MHz channel can be located in 16 tone intervals (32 tones apart for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the 1x HE-STF sequence may be composed of ⁇ M sequence, M sequence, a, 0, b, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -1 is multiplied by the third and fourth M sequences.
  • a and b represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a may be ( ⁇ 1 / 2) (1 + j), and b may be ( ⁇ 1 / 2) (-1-j).
  • the 1x HE-STF sequence is the M sequence, M sequence, ( ⁇ 1 / 2) (1+ in 16-tone increments (HES_-496,496 (-496: 16: 496)) from tone index -496 to 496.
  • j 0, ( ⁇ 1 / 2) (-1-j), -1XM sequence, and -1XM sequence may be defined to be sequentially mapped.
  • 62 HE-STF tones on the 80 MHz channel can be located at 16 tone intervals (with 32 tone intervals for tones located at tone indices -16 and 16), with zero values.
  • One HE-STF tone may be located at tone index zero.
  • the HE-STF sequence for the period of 1.6 ms it may be configured based on the M sequence defined in Equation 31, and more specifically, may be determined as in Equation 33.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, 0, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • the second M sequence is multiplied by -1. Therefore, a 2x HE-STF sequence in a 20 MHz channel is defined so that M sequences, 0 and -1XM sequences are sequentially mapped in 8 tone units (HES_-120,120 (-120: 8: 120)) from tone index -120 to 120. Can be.
  • 30 HE-STF tones with no 0 value can be placed in 8 tone intervals on a 20 MHz channel (except 16 tones for tones located at tone indices -8 and 8), with 0 values.
  • One HE-STF tone may be located at tone index zero.
  • the 2x HE-STF sequence may be composed of ⁇ M sequence, M sequence, 0, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • j is multiplied by the third M sequence
  • -j is multiplied by the fourth M sequence.
  • a 2x HE-STF sequence on a 40 MHz channel is an M sequence, M sequence, 0, jXM sequence, in 8-tone units (HES_-248,248 (-248: 8: 248)) above tone index -248 and below 248.
  • the j X M sequences may be defined to be mapped sequentially, and 0 may be defined to be mapped to tones HES_-248 and 248 ( ⁇ 248) located at tone indices -248 and 248, respectively. That is, tones located at the tone index ⁇ 248 may be nulled since they correspond to guard tones (left / light guard tones).
  • 60 HE-STF tones in the 40 MHz channel can be located at 8 tone intervals (with 16 tone intervals for tones located at tone indexes -8 and 8), with 0 values.
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 248, respectively.
  • a 2x HE-STF sequence may consist of ⁇ M sequence, M sequence, M sequence, M sequence, a, b, 0, c, d, M sequence, M sequence, M sequence, M sequence ⁇ .
  • the M sequence may be multiplied by any one of 1, -1, j, and -j.
  • -1 is multiplied by the second, third, fourth, sixth, seventh, and eighth M sequences, respectively.
  • a to d represent preset coefficients, and ( ⁇ 1 / 2) (1 + j), ( ⁇ 1 / 2) (1-j), ( ⁇ 1 / 2) (-1+ j) and ( ⁇ 1 / 2) (-1-j) may be determined as a value capable of minimizing PAPR.
  • a is ( ⁇ 1 / 2) (-1-j)
  • b is ( ⁇ 1 / 2) (-1-j)
  • c is ( ⁇ 1 / 2) (-1-j)
  • d May be ( ⁇ 1 / 2) (1 + j).
  • a 2x HE-STF sequence on an 80 MHz channel is an M sequence, -1XM sequence, -1XM sequence, -1XM in 8-tone increments (HES_-504,504 (-504: 8: 504)) above tone index -504 and below 504 Sequence, ( ⁇ 1 / 2) (-1-j), ( ⁇ 1 / 2) (-1-j), 0, ( ⁇ 1 / 2) (-1-j), ( ⁇ 1 / 2) ( 1 + j), M sequence, -1XM sequence, -1XM sequence, and -1XM sequence can be defined to be sequentially mapped, and tones (HES_-504,504 ( ⁇ 504)) located at tone indices -504 and 504 respectively A value of zero can be defined to map. That is, tones located at the tone index ⁇ 504 may be nulled since they correspond to guard tones (left / light guard tones).
  • 124 HE-STF tones that do not have a zero value on the 80 MHz channel can be located at eight tone intervals (except for 16 tone intervals for tones located at tone indexes -8 and 8).
  • Three HE-STF tones may be located at tone indexes 0 and ⁇ 504, respectively.
  • 1x, 2x HE-STF sequence which can be applied to 802.11ax system and has an optimal PAPR performance has been proposed.
  • the M sequences proposed in the above embodiments were determined to have optimal PAPR performance by jointly considering the 1x and 2x HE-STF sequences, and by using the determined M sequences, other coefficients were also optimized.
  • 1x and 2x HE STF sequences with optimal PAPR performance were proposed.
  • the M sequences proposed in the first to ninth embodiments are to find the M sequence having the optimized PAPR performance in consideration of the PAPR of all resource units in the 2x HE-STF situation, which is transmitted in the 20 MHz channel.
  • Optimized PAPR performance is also guaranteed for 2x HE-STF in HE-STF and other channel transmissions.
  • the M sequence of the tenth embodiment finds an M sequence having an optimized PAPR performance in consideration of PAPR of all resource units in a 2x HE-STF situation, which is transmitted in a 40 MHz channel, which is 1x HE-STF and other channels. Optimized PAPR performance is also guaranteed at 2x HE-STF in transmission.
  • FIG. 19 is a flowchart illustrating a PPDU transmission method of an STA device according to an embodiment of the present invention.
  • the embodiments described above with reference to the flowchart can be equally applied. Therefore, a description overlapping with the above description will be omitted.
  • the STA may generate a HE-STF sequence (S1901).
  • the generated HE-STF sequence may be generated as a sequence having an optimized PAPR performance, and may be configured by a combination of an M sequence and a zero value.
  • Detailed description of the HE-STF sequence proposed in the present invention is as described above in the first to eleventh embodiments.
  • the STA may generate a PPDU (S1902).
  • the STA may generate a HE-STF field based on the HE-STF sequence generated in the previous step, and may generate a PPDU in which the HE-STF field is inserted.
  • the STA may transmit the PPDU (S1903).
  • the STA may DL-transmit the PPDU generated in the previous step.
  • the HE-STF field inserted in the PPDU may be transmitted through a (frequency, sub) channel (eg, 20 MHz / 40 MHz / 80 MHz).
  • the HE-STF sequence of the HE-STF field may be mapped to preset tones included in the tones included in the transmission channel.
  • 20 is a block diagram of each STA apparatus according to an embodiment of the present invention.
  • the STA apparatus 2000 may include a memory 2010, a processor 2020, and an RF unit 2030.
  • the STA device 2000 may be an HE STA device, and may be an AP or a non-AP STA.
  • the RF unit 2030 may be connected to the processor 2020 to transmit / receive a radio signal.
  • the RF unit 2030 may upconvert data received from the processor into a transmission / reception band to transmit a signal.
  • the processor 2020 may be connected to the RF unit 2030 to implement a physical layer and / or MAC layer according to the IEEE 802.11 system.
  • the processor 2020 may be configured to perform an operation according to various embodiments of the present disclosure according to the drawings and description described above.
  • a module implementing the operation of the STA 2000 according to various embodiments of the present disclosure described above may be stored in the memory 2010 and executed by the processor 2020.
  • the memory 2010 is connected to the processor 2020 and stores various information for driving the processor 2020.
  • the memory 2010 may be included in the processor 2020 or may be installed outside the processor 2020 and connected to the processor 2020 by known means.
  • the STA apparatus 2000 may include a single antenna or multiple antennas.
  • the specific configuration of the STA apparatus 2000 of FIG. 20 may be implemented such that the matters described in the above-described various embodiments of the present invention are applied independently or two or more embodiments are simultaneously applied.
  • each component or feature is to be considered optional unless stated otherwise.
  • Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention.
  • the order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.
  • Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof.
  • an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.
  • ASICs application specific integrated circuits
  • DSPs digital signal processors
  • DSPDs digital signal processing devices
  • PLDs programmable logic devices
  • FPGAs field programmable gate arrays
  • processors controllers, microcontrollers, microprocessors, and the like.
  • an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above.
  • the software code may be stored in memory and driven by the processor.
  • the memory may be located inside or outside the processor, and may exchange data with the processor by various known means.
  • the data transmission and reception method has been described with reference to the example applied to the IEEE 802.11 system, but it is possible to apply to various wireless communication systems in addition to the IEEE 802.11 system.

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  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé pour un appareil de station (STA) transmettant une unité de données de protocole physique (PPDU) dans un système de réseau local sans fil (WLAN), selon un mode de réalisation de la présente invention, qui comprend les étapes consistant à : générer une séquence de champ d'apprentissage court à efficacité élevée (HE-STF) ; générer une PPDU comprenant un champ HE-STF configuré sur la base de la séquence HE-STF ; et transmettre la PPDU, le champ HE-STF inclus dans la PPDU étant transmis par un canal, et la séquence HE-STF pouvant être configurée sur la base d'une séquence M comprenant {-1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1}*(√1/2)(1+j).
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