Patent Publication Number: US-2022232621-A1

Title: Method and apparatus for filtering ppdu in wireless communication system

Description:
BACKGROUND 
     Field of the disclosure 
     The present specification relates to a technique for filtering a PPDU in a WLAN system, and more particularly, to a method and an apparatus for filtering a PPDU in a WLAN system. 
     Related Art 
     Wireless network technologies may include various types of wireless local area networks (WLAN). WLAN may be used for interconnecting neighboring devices by adopting networking protocols that are extensively used. The various technical features that are described in this specification may be applied to a random communication standard, such as Wi-Fi, or more generally, any one of the IEEE 802.11 wireless protocol group. 
     The present specification either enhances the conventional (or existing) IEEE 802.11p specification or proposes technical characteristics that can be used in a new communication standard. The new communication standard may be a Next Generation V2X (NGV) standard, which is currently being discussed. 
     Meanwhile, in the IEEE standard, various types or formats of Physical Protocol Data Units (PPDUs) are defined. Transmitting and receiving stations (STA) may be configured to use an auto-detection rule to identify the type/format of the PPDU being transmitted and received. 
     SUMMARY 
     For smooth Vehicle-to-Everything (V2X) support in 5.9 GHz band, technology development for Next Generation V2X (NGV) is in progress in consideration of DSRC (802.11p standard) throughput improvement and highspeed support. In the NGV standard (i.e., 802.11bd standard), wide bandwidth (20 MHz) transmission is being considered instead of the conventional 10 MHz transmission to improve 2× throughput. In addition, the NGV standard must support operations such as interoperability/backward compatibility/coexistence with the existing 802.11p standard. 
     The NGV standard may support various services. Accordingly, the STA supporting the NGV standard (i.e., the NGV STA) should classify (or filter) the PPDU related to the service it can support. A specific operation method for the above technical objects may be required. 
     An example according to the present specification relates to a method and/or apparatus for filtering NGV PPDUs in a wireless communication system. 
     An STA according to an example of the present specification may receive an NGV Physical Protocol Data Unit (PPDU). The NGV PPDU may include a first control field and a second control field. The first control field may include first information related to the transmission time of the NGV PPDU, and the second control field may include second information related to the bandwidth of the NGV PPDU. 
     The STA according to an example of the present specification may filter the NGV PPDU based on the second control field. 
     The STA according to an example of the present specification may defer channel access based on the first control field. 
     TECHNICAL EFFECTS OF THE DISCLOSURE 
     The present specification proposes technical features supporting a situation in which the 5.9 GHz band is used in various WLAN systems (e.g., IEEE 802.11bd systems). Based on various examples of the present specification, throughput improvement and high speed of Dedicated Short Range Communication (DSRC or 802.11p) may be supported for smooth V2X support in the 5.9 GHz band. 
     Specifically, according to the present specification, the NGV STA may filter out PPDUs not related to the service to be performed in the WLAN system. Therefore, according to an example of the present specification, technical effects in which the NGV STA can filter the unnecessary PPDU without decoding may be achieved. Accordingly, technical effects in which the NGV STA can efficiently operate may be achieved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an example of a transmitting apparatus and/or receiving apparatus of the present specification. 
         FIG. 2  is a conceptual view illustrating the structure of a wireless local area network (WLAN). 
         FIG. 3  illustrates a general link setup process. 
         FIG. 4  illustrates an example of a PPDU used in an IEEE standard. 
         FIG. 5  illustrates a layout of resource units (RUs) used in a band of 20 MHz. 
         FIG. 6  illustrates a layout of RUs used in a band of 40 MHz. 
         FIG. 7  illustrates a layout of RUs used in a band of 80 MHz. 
         FIG. 8  illustrates a structure of an HE-SIG-B field. 
         FIG. 9  illustrates an example in which a plurality of user STAs are allocated to the same RU through a MU-MIMO scheme. 
         FIG. 10  illustrates an operation based on UL-MU. 
         FIG. 11  illustrates an example of a trigger frame. 
         FIG. 12  illustrates an example of a common information field of a trigger frame. 
         FIG. 13  illustrates an example of a subfield included in a per user information field. 
         FIG. 14  describes a technical feature of the UORA scheme. 
         FIG. 15  illustrates an example of a channel used/supported/defined within a 2.4 GHz band. 
         FIG. 16  illustrates an example of a channel used/supported/defined within a 5 GHz band. 
         FIG. 17  illustrates an example of a channel used/supported/defined within a 6 GHz band. 
         FIG. 18  illustrates an example of a PPDU used in the present specification. 
         FIG. 19  illustrates an example of a modified transmission device and/or receiving device of the present specification. 
         FIG. 20  shows a band plan of 5.9 GHz DSRC. 
         FIG. 21  shows a format of an NGV PPDU for 10 a MHz transmission. 
         FIG. 22  shows another format of an NGV PPDU for a 20 MHz transmission. 
         FIG. 23  shows a diagram for explaining an example in which NGV PPDUs are filtered. 
         FIG. 24  shows a diagram for explaining another example in which the NGV PPDU is filtered. 
         FIG. 25  shows a diagram for explaining an example in which an 11p PPDU is filtered. 
         FIG. 26  shows a diagram for explaining another example in which an 11p PPDU is filtered. 
         FIG. 27  shows a flowchart illustrating an operation of an NGV STA for filtering a PPDU. 
         FIG. 28  shows a diagram for explaining an embodiment in which a PPDU is filtered based on service-related information. 
         FIG. 29  shows a flowchart illustrating another operation of an NGV STA for filtering a PPDU. 
         FIG. 30  shows a flowchart illustrating an operation of an STA for filtering a PPDU. 
         FIG. 31  shows a vehicle or an autonomous driving vehicle applied to the present specification. 
         FIG. 32  shows an example of a vehicle that is applied to the present specification. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     In the present specification, “A or B” may mean “only A”, “only B” or “both A and B”. In other words, in the present specification, “A or B” may be interpreted as “A and/or B”. For example, in the present specification, “A, B, or C” may mean “only A”, “only B”, “only C”, or “any combination of A, B, C”. 
     A slash (/) or comma used in the present specification may mean “and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, B, or C”. 
     In the present specification, “at least one of A and B” may mean “only A”, “only B”, or “both A and B”. In addition, in the present specification, the expression “at least one of A or B” or “at least one of A and/or B” may be interpreted as “at least one of A and B”. 
     In addition, in the present specification, “at least one of A, B, and C” may mean “only A”, “only B”, “only C”, or “any combination of A, B, and C”. In addition, “at least one of A, B, or C” or “at least one of A, B, and/or C” may mean “at least one of A, B, and C”. 
     In addition, a parenthesis used in the present specification may mean “for example”. Specifically, when indicated as “control information (EHT-signal)”, it may mean that “EHT-signal” is proposed as an example of the “control information”. In other words, the “control information” of the present specification is not limited to “EHT-signal”, and “EHT-signal” may be proposed as an example of the “control information”. In addition, when indicated as “control information (i.e., EHT-signal)”, it may also mean that “EHT-signal” is proposed as an example of the “control information”. 
     Technical features described individually in one figure in the present specification may be individually implemented, or may be simultaneously implemented. 
     The following example of the present specification may be applied to various wireless communication systems. For example, the following example of the present specification may be applied to a wireless local area network (WLAN) system. For example, the present specification may be applied to the IEEE 802.11a/g/n/ac standard or the IEEE 802.11ax standard. In addition, the present specification may also be applied to the newly proposed EHT standard or IEEE 802.11be standard. In addition, the example of the present specification may also be applied to a new WLAN standard enhanced from the EHT standard or the IEEE 802.11be standard. In addition, the example of the present specification may be applied to a mobile communication system. For example, it may be applied to a mobile communication system based on long term evolution (LTE) depending on a 3 rd  generation partnership project (3GPP) standard and based on evolution of the LTE. In addition, the example of the present specification may be applied to a communication system of a 5G NR standard based on the 3GPP standard. 
     Hereinafter, in order to describe a technical feature of the present specification, a technical feature applicable to the present specification will be described. 
       FIG. 1  shows an example of a transmitting apparatus and/or receiving apparatus of the present specification. 
     In the example of  FIG. 1 , various technical features described below may be performed.  FIG. 1  relates to at least one station (STA). For example, STAs  110  and  120  of the present specification may also be called in various terms such as a mobile terminal, a wireless device, a wireless transmit/receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit, or simply a user. The STAs  110  and  120  of the present specification may also be called in various terms such as a network, a base station, a node-B, an access point (AP), a repeater, a router, a relay, or the like. The STAs  110  and  120  of the present specification may also be referred to as various names such as a receiving apparatus, a transmitting apparatus, a receiving STA, a transmitting STA, a receiving device, a transmitting device, or the like. 
     For example, the STAs  110  and  120  may serve as an AP or a non-AP. That is, the STAs  110  and  120  of the present specification may serve as the AP and/or the non-AP. 
     The STAs  110  and  120  of the present specification may support various communication standards together in addition to the IEEE 802.11 standard. For example, a communication standard (e.g., LTE, LTE-A, 5G NR standard) or the like based on the 3GPP standard may be supported. In addition, the STA of the present specification may be implemented as various devices such as a mobile phone, a vehicle, a personal computer, or the like. In addition, the STA of the present specification may support communication for various communication services such as voice calls, video calls, data communication, and self-driving (autonomous-driving), or the like. 
     The STAs  110  and  120  of the present specification may include a medium access control (MAC) conforming to the IEEE 802.11 standard and a physical layer interface for a radio medium. 
     The STAs  110  and  120  will be described below with reference to a sub-figure ( a ) of  FIG. 1 . 
     The first STA  110  may include a processor  111 , a memory  112 , and a transceiver  113 . The illustrated process, memory, and transceiver may be implemented individually as separate chips, or at least two blocks/functions may be implemented through a single chip. 
     The transceiver  113  of the first STA performs a signal transmission/reception operation. Specifically, an IEEE 802.11 packet (e.g., IEEE 802.11a/b/g/n/ac/ax/be, etc.) may be transmitted/received. 
     For example, the first STA  110  may perform an operation intended by an AP. For example, the processor  111  of the AP may receive a signal through the transceiver  113 , process a reception (RX) signal, generate a transmission (TX) signal, and provide control for signal transmission. The memory  112  of the AP may store a signal (e.g., RX signal) received through the transceiver  113 , and may store a signal (e.g., TX signal) to be transmitted through the transceiver. 
     For example, the second STA  120  may perform an operation intended by a non-AP STA. For example, a transceiver  123  of a non-AP performs a signal transmission/reception operation. Specifically, an IEEE 802.11 packet (e.g., IEEE 802.11a/b/g/n/ac/ax/be packet, etc.) may be transmitted/received. 
     For example, a processor  121  of the non-AP STA may receive a signal through the transceiver  123 , process an RX signal, generate a TX signal, and provide control for signal transmission. A memory  122  of the non-AP STA may store a signal (e.g., RX signal) received through the transceiver  123 , and may store a signal (e.g., TX signal) to be transmitted through the transceiver. 
     For example, an operation of a device indicated as an AP in the specification described below may be performed in the first STA  110  or the second STA  120 . For example, if the first STA  110  is the AP, the operation of the device indicated as the AP may be controlled by the processor  111  of the first STA  110 , and a related signal may be transmitted or received through the transceiver  113  controlled by the processor  111  of the first STA  110 . In addition, control information related to the operation of the AP or a TX/RX signal of the AP may be stored in the memory  112  of the first STA  110 . In addition, if the second STA  120  is the AP, the operation of the device indicated as the AP may be controlled by the processor  121  of the second STA  120 , and a related signal may be transmitted or received through the transceiver  123  controlled by the processor  121  of the second STA  120 . In addition, control information related to the operation of the AP or a TX/RX signal of the AP may be stored in the memory  122  of the second STA  120 . 
     For example, in the specification described below, an operation of a device indicated as a non-AP (or user-STA) may be performed in the first STA  110  or the second STA  120 . For example, if the second STA  120  is the non-AP, the operation of the device indicated as the non-AP may be controlled by the processor  121  of the second STA  120 , and a related signal may be transmitted or received through the transceiver  123  controlled by the processor  121  of the second STA  120 . In addition, control information related to the operation of the non-AP or a TX/RX signal of the non-AP may be stored in the memory  122  of the second STA  120 . For example, if the first STA  110  is the non-AP, the operation of the device indicated as the non-AP may be controlled by the processor  111  of the first STA  110 , and a related signal may be transmitted or received through the transceiver  113  controlled by the processor  111  of the first STA  110 . In addition, control information related to the operation of the non-AP or a TX/RX signal of the non-AP may be stored in the memory  112  of the first STA  110 . 
     In the specification described below, a device called a (transmitting/receiving) STA, a first STA, a second STA, a STA1, a STA2, an AP, a first AP, a second AP, an AP1, an AP2, a (transmitting/receiving) terminal, a (transmitting/receiving) device, a (transmitting/receiving) apparatus, a network, or the like may imply the STAs  110  and  120  of  FIG. 1 . For example, a device indicated as, without a specific reference numeral, the (transmitting/receiving) STA, the first STA, the second STA, the STA1, the STA2, the AP, the first AP, the second AP, the AN, the AP2, the (transmitting/receiving) terminal, the (transmitting/receiving) device, the (transmitting/receiving) apparatus, the network, or the like may imply the STAs  110  and  120  of  FIG. 1 . For example, in the following example, an operation in which various STAs transmit/receive a signal (e.g., a PPDU) may be performed in the transceivers  113  and  123  of  FIG. 1 . In addition, in the following example, an operation in which various STAs generate a TX/RX signal or perform data processing and computation in advance for the TX/RX signal may be performed in the processors  111  and  121  of  FIG. 1 . For example, an example of an operation for generating the TX/RX signal or performing the data processing and computation in advance may include: 1) an operation of determining/obtaining/configuring/computing/decoding/encoding bit information of a sub-field (SIG, STF, LTF, Data) included in a PPDU; 2) an operation of determining/configuring/obtaining a time resource or frequency resource (e.g., a subcarrier resource) or the like used for the sub-field (SIG, STF, LTF, Data) included the PPDU; 3) an operation of determining/configuring/obtaining a specific sequence (e.g., a pilot sequence, an STF/LTF sequence, an extra sequence applied to SIG) or the like used for the sub-field (SIG, STF, LTF, Data) field included in the PPDU; 4) a power control operation and/or power saving operation applied for the STA; and 5) an operation related to determining/obtaining/configuring/decoding/encoding or the like of an ACK signal. In addition, in the following example, a variety of information used by various STAs for determining/obtaining/configuring/computing/decoding/decoding a TX/RX signal (e.g., information related to a field/subfield/control field/parameter/power or the like) may be stored in the memories  112  and  122  of  FIG. 1 . 
     The aforementioned device/STA of the sub-figure ( a ) of  FIG. 1  may be modified as shown in the sub-figure ( b ) of  FIG. 1 . Hereinafter, the STAs  110  and  120  of the present specification will be described based on the sub-figure ( b ) of  FIG. 1 . 
     For example, the transceivers  113  and  123  illustrated in the sub-figure ( b ) of  FIG. 1  may perform the same function as the aforementioned transceiver illustrated in the sub-figure ( a ) of  FIG. 1 . For example, processing chips  114  and  124  illustrated in the sub-figure ( b ) of  FIG. 1  may include the processors  111  and  121  and the memories  112  and  122 . The processors  111  and  121  and memories  112  and  122  illustrated in the sub-figure ( b ) of  FIG. 1  may perform the same function as the aforementioned processors  111  and  121  and memories  112  and  122  illustrated in the sub-figure ( a ) of  FIG. 1 . 
     A mobile terminal, a wireless device, a wireless transmit/receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit, a user, a user STA, a network, a base station, a Node-B, an access point (AP), a repeater, a router, a relay, a receiving unit, a transmitting unit, a receiving STA, a transmitting STA, a receiving device, a transmitting device, a receiving apparatus, and/or a transmitting apparatus, which are described below, may imply the STAs  110  and  120  illustrated in the sub-figure ( a )/( b ) of  FIG. 1 , or may imply the processing chips  114  and  124  illustrated in the sub-figure ( b ) of  FIG. 1 . That is, a technical feature of the present specification may be performed in the STAs  110  and  120  illustrated in the sub-figure ( a )/( b ) of  FIG. 1 , or may be performed only in the processing chips  114  and  124  illustrated in the sub-figure ( b ) of  FIG. 1 . For example, a technical feature in which the transmitting STA transmits a control signal may be understood as a technical feature in which a control signal generated in the processors  111  and  121  illustrated in the sub-figure ( a )/( b ) of  FIG. 1  is transmitted through the transceivers  113  and  123  illustrated in the sub-figure ( a )/( b ) of  FIG. 1 . Alternatively, the technical feature in which the transmitting STA transmits the control signal may be understood as a technical feature in which the control signal to be transferred to the transceivers  113  and  123  is generated in the processing chips  114  and  124  illustrated in the sub-figure ( b ) of  FIG. 1 . 
     For example, a technical feature in which the receiving STA receives the control signal may be understood as a technical feature in which the control signal is received by means of the transceivers  113  and  123  illustrated in the sub-figure ( a ) of  FIG. 1 . Alternatively, the technical feature in which the receiving STA receives the control signal may be understood as the technical feature in which the control signal received in the transceivers  113  and  123  illustrated in the sub-figure ( a ) of  FIG. 1  is obtained by the processors  111  and  121  illustrated in the sub-figure ( a ) of  FIG. 1 . Alternatively, the technical feature in which the receiving STA receives the control signal may be understood as the technical feature in which the control signal received in the transceivers  113  and  123  illustrated in the sub-figure ( b ) of  FIG. 1  is obtained by the processing chips  114  and  124  illustrated in the sub-figure ( b ) of  FIG. 1 . 
     Referring to the sub-figure ( b ) of  FIG. 1 , software codes  115  and  125  may be included in the memories  112  and  122 . The software codes  115  and  126  may include instructions for controlling an operation of the processors  111  and  121 . The software codes  115  and  125  may be included as various programming languages. 
     The processors  111  and  121  or processing chips  114  and  124  of  FIG. 1  may include an application-specific integrated circuit (ASIC), other chipsets, a logic circuit and/or a data processing device. The processor may be an application processor (AP). For example, the processors  111  and  121  or processing chips  114  and  124  of  FIG. 1  may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modulator and demodulator (modem). For example, the processors  111  and  121  or processing chips  114  and  124  of  FIG. 1  may be SNAPDRAGON™ series of processors made by Qualcomm®, EXYNOS™ series of processors made by Samsung®, A series of processors made by Apple®, HELIO™ series of processors made by MediaTek®, ATOM™ series of processors made by Intel® or processors enhanced from these processors. 
     In the present specification, an uplink may imply a link for communication from a non-AP STA to an SP STA, and an uplink PPDU/packet/signal or the like may be transmitted through the uplink. In addition, in the present specification, a downlink may imply a link for communication from the AP STA to the non-AP STA, and a downlink PPDU/packet/signal or the like may be transmitted through the downlink. 
       FIG. 2  is a conceptual view illustrating the structure of a wireless local area network (WLAN). 
     An upper part of  FIG. 2  illustrates the structure of an infrastructure basic service set (BSS) of institute of electrical and electronic engineers (IEEE) 802.11. 
     Referring the upper part of  FIG. 2 , the wireless LAN system may include one or more infrastructure BSSs  200  and  205  (hereinafter, referred to as BSS). The BSSs  200  and  205  as a set of an AP and a STA such as an access point (AP)  225  and a station (STA1)  200 - 1  which are successfully synchronized to communicate with each other are not concepts indicating a specific region. The BSS  205  may include one or more STAs  205 - 1  and  205 - 2  which may be joined to one AP  230 . 
     The BSS may include at least one STA, APs providing a distribution service, and a distribution system (DS)  210  connecting multiple APs. 
     The distribution system  210  may implement an extended service set (ESS)  240  extended by connecting the multiple BSSs  200  and  205 . The ESS  240  may be used as a term indicating one network configured by connecting one or more APs  225  or  230  through the distribution system  210 . The AP included in one ESS  240  may have the same service set identification (SSID). 
     A portal  220  may serve as a bridge which connects the wireless LAN network (IEEE 802.11) and another network (e.g., 802.X). 
     In the BSS illustrated in the upper part of  FIG. 2 , a network between the APs  225  and  230  and a network between the APs  225  and  230  and the STAs  200 - 1 ,  205 - 1 , and  205 - 2  may be implemented. However, the network is configured even between the STAs without the APs  225  and  230  to perform communication. A network in which the communication is performed by configuring the network even between the STAs without the APs  225  and  230  is defined as an Ad-Hoc network or an independent basic service set (IBSS). 
     A lower part of  FIG. 2  illustrates a conceptual view illustrating the IBSS. 
     Referring to the lower part of  FIG. 2 , the IBSS is a BSS that operates in an Ad-Hoc mode. Since the IBSS does not include the access point (AP), a centralized management entity that performs a management function at the center does not exist. That is, in the IBSS, STAs  250 - 1 ,  250 - 2 ,  250 - 3 ,  255 - 4 , and  255 - 5  are managed by a distributed manner In the IBSS, all STAs  250 - 1 ,  250 - 2 ,  250 - 3 ,  255 - 4 , and  255 - 5  may be constituted by movable STAs and are not permitted to access the DS to constitute a self-contained network. 
       FIG. 3  illustrates a general link setup process. 
     In S 310 , a STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, to access a network, the STA needs to discover a participating network. The STA needs to identify a compatible network before participating in a wireless network, and a process of identifying a network present in a particular area is referred to as scanning Scanning methods include active scanning and passive scanning. 
       FIG. 3  illustrates a network discovery operation including an active scanning process. In active scanning, a STA performing scanning transmits a probe request frame and waits for a response to the probe request frame in order to identify which AP is present around while moving to channels. A responder transmits a probe response frame as a response to the probe request frame to the STA having transmitted the probe request frame. Here, the responder may be a STA that transmits the last beacon frame in a BSS of a channel being scanned. In the BSS, since an AP transmits a beacon frame, the AP is the responder. In an IBSS, since STAs in the IBSS transmit a beacon frame in turns, the responder is not fixed. For example, when the STA transmits a probe request frame via channel  1  and receives a probe response frame via channel  1 , the STA may store BSS-related information included in the received probe response frame, may move to the next channel (e.g., channel  2 ), and may perform scanning (e.g., transmits a probe request and receives a probe response via channel  2 ) by the same method. 
     Although not shown in  FIG. 3 , scanning may be performed by a passive scanning method. In passive scanning, a STA performing scanning may wait for a beacon frame while moving to channels. A beacon frame is one of management frames in IEEE 802.11 and is periodically transmitted to indicate the presence of a wireless network and to enable the STA performing scanning to find the wireless network and to participate in the wireless network. In a BSS, an AP serves to periodically transmit a beacon frame. In an IBSS, STAs in the IBSS transmit a beacon frame in turns. Upon receiving the beacon frame, the STA performing scanning stores information related to a BSS included in the beacon frame and records beacon frame information in each channel while moving to another channel. The STA having received the beacon frame may store BSS-related information included in the received beacon frame, may move to the next channel, and may perform scanning in the next channel by the same method. 
     After discovering the network, the STA may perform an authentication process in S 320 . The authentication process may be referred to as a first authentication process to be clearly distinguished from the following security setup operation in S 340 . The authentication process in S 320  may include a process in which the STA transmits an authentication request frame to the AP and the AP transmits an authentication response frame to the STA in response. The authentication frames used for an authentication request/response are management frames. 
     The authentication frames may include information related to an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), and a finite cyclic group. 
     The STA may transmit the authentication request frame to the AP. The AP may determine whether to allow the authentication of the STA based on the information included in the received authentication request frame. The AP may provide the authentication processing result to the STA via the authentication response frame. 
     When the STA is successfully authenticated, the STA may perform an association process in S 330 . The association process includes a process in which the STA transmits an association request frame to the AP and the AP transmits an association response frame to the STA in response. The association request frame may include, for example, information related to various capabilities, a beacon listen interval, a service set identifier (SSID), a supported rate, a supported channel, RSN, a mobility domain, a supported operating class, a traffic indication map (TIM) broadcast request, and an interworking service capability. The association response frame may include, for example, information related to various capabilities, a status code, an association ID (AID), a supported rate, an enhanced distributed channel access (EDCA) parameter set, a received channel power indicator (RCPI), a received signal-to-noise indicator (RSNI), a mobility domain, a timeout interval (association comeback time), an overlapping BSS scanning parameter, a TIM broadcast response, and a QoS map. 
     In S 340 , the STA may perform a security setup process. The security setup process in S 340  may include a process of setting up a private key through four-way handshaking, for example, through an extensible authentication protocol over LAN (EAPOL) frame. 
       FIG. 4  illustrates an example of a PPDU used in an IEEE standard. 
     As illustrated, various types of PHY protocol data units (PPDUs) are used in IEEE a/g/n/ac standards. Specifically, an LTF and a STF include a training signal, a SIG-A and a SIG-B include control information for a receiving STA, and a data field includes user data corresponding to a PSDU (MAC PDU/aggregated MAC PDU). 
       FIG. 4  also includes an example of an HE PPDU according to IEEE 802.11ax. The HE PPDU according to  FIG. 4  is an illustrative PPDU for multiple users. An HE-SIG-B may be included only in a PPDU for multiple users, and an HE-SIG-B may be omitted in a PPDU for a single user. 
     As illustrated in  FIG. 4 , the HE-PPDU for multiple users (MUs) may include a legacy-short training field (L-STF), a legacy-long training field (L-LTF), a legacy-signal (L-SIG), a high efficiency-signal A (HE-SIG A), a high efficiency-signal-B (HE-SIG B), a high efficiency-short training field (HE-STF), a high efficiency-long training field (HE-LTF), a data field (alternatively, an MAC payload), and a packet extension (PE) field. The respective fields may be transmitted for illustrated time periods (i.e., 4 or 8 μs). 
     Hereinafter, a resource unit (RU) used for a PPDU is described. An RU may include a plurality of subcarriers (or tones). An RU may be used to transmit a signal to a plurality of STAs according to OFDMA. Further, an RU may also be defined to transmit a signal to one STA. An RU may be used for an STF, an LTF, a data field, or the like. 
       FIG. 5  illustrates a layout of resource units (RUs) used in a band of 20 MHz. 
     As illustrated in  FIG. 5 , resource units (RUs) corresponding to different numbers of tones (i.e., subcarriers) may be used to form some fields of an HE-PPDU. For example, resources may be allocated in illustrated RUs for an HE-STF, an HE-LTF, and a data field. 
     As illustrated in the uppermost part of  FIG. 5 , a 26-unit (i.e., a unit corresponding to 26 tones) may be disposed. Six tones may be used for a guard band in the leftmost band of the 20 MHz band, and five tones may be used for a guard band in the rightmost band of the 20 MHz band. Further, seven DC tones may be inserted in a center band, that is, a DC band, and a 26-unit corresponding to 13 tones on each of the left and right sides of the DC band may be disposed. A 26-unit, a 52-unit, and a 106-unit may be allocated to other bands. Each unit may be allocated for a receiving STA, that is, a user. 
     The layout of the RUs in  FIG. 5  may be used not only for a multiple users (MUs) but also for a single user (SU), in which case one 242-unit may be used and three DC tones may be inserted as illustrated in the lowermost part of  FIG. 5 . 
     Although  FIG. 5  proposes RUs having various sizes, that is, a 26-RU, a 52-RU, a 106-RU, and a 242-RU, specific sizes of RUs may be extended or increased. Therefore, the present embodiment is not limited to the specific size of each RU (i.e., the number of corresponding tones). 
       FIG. 6  illustrates a layout of RUs used in a band of 40 MHz. 
     Similarly to  FIG. 5  in which RUs having various sizes are used, a 26-RU, a 52-RU, a 106-RU, a 242-RU, a 484-RU, and the like may be used in an example of  FIG. 6 . Further, five DC tones may be inserted in a center frequency, 12 tones may be used for a guard band in the leftmost band of the 40 MHz band, and 11 tones may be used for a guard band in the rightmost band of the 40 MHz band. 
     As illustrated in  FIG. 6 , when the layout of the RUs is used for a single user, a 484-RU may be used. The specific number of RUs may be changed similarly to  FIG. 5 . 
       FIG. 7  illustrates a layout of RUs used in a band of 80 MHz. 
     Similarly to  FIG. 5  and  FIG. 6  in which RUs having various sizes are used, a 26-RU, a 52-RU, a 106-RU, a 242-RU, a 484-RU, a 996-RU, and the like may be used in an example of  FIG. 7 . Further, seven DC tones may be inserted in the center frequency, 12 tones may be used for a guard band in the leftmost band of the 80 MHz band, and 11 tones may be used for a guard band in the rightmost band of the 80 MHz band. In addition, a 26-RU corresponding to 13 tones on each of the left and right sides of the DC band may be used. 
     As illustrated in  FIG. 7 , when the layout of the RUs is used for a single user, a 996-RU may be used, in which case five DC tones may be inserted. 
     In the meantime, the fact that the specific number of RUs can be changed is the same as those of  FIGS. 5 and 6 . 
     The RU arrangement (i.e., RU location) shown in  FIGS. 5 to 7  can be applied to a new wireless LAN system (e.g. EHT system) as it is. Meanwhile, for the 160 MHz band supported by the new WLAN system, the RU arrangement for 80 MHz (i.e., an example of  FIG. 7 ) may be repeated twice, or the RU arrangement for the 40 MHz (i.e., an example of  FIG. 6 ) may be repeated 4 times. In addition, when the EHT PPDU is configured for the 320 MHz band, the arrangement of the RU for 80 MHz (i.e., an example of  FIG. 7 ) may be repeated 4 times or the arrangement of the RU for 40 MHz (i.e., an example of  FIG. 6 ) may be repeated 8 times. 
     One RU of the present specification may be allocated for a single STA (e.g., a single non-AP STA). Alternatively, a plurality of RUs may be allocated for one STA (e.g., a non-AP STA). 
     The RU described in the present specification may be used in uplink (UL) communication and downlink (DL) communication. For example, when UL-MU communication which is solicited by a trigger frame is performed, a transmitting STA (e.g., an AP) may allocate a first RU (e.g., 26/52/106/242-RU, etc.) to a first STA through the trigger frame, and may allocate a second RU (e.g., 26/52/106/242-RU, etc.) to a second STA. Thereafter, the first STA may transmit a first trigger-based PPDU based on the first RU, and the second STA may transmit a second trigger-based PPDU based on the second RU. The first/second trigger-based PPDU is transmitted to the AP at the same (or overlapped) time period. 
     For example, when a DL MU PPDU is configured, the transmitting STA (e.g., AP) may allocate the first RU (e.g., 26/52/106/242-RU. etc.) to the first STA, and may allocate the second RU (e.g., 26/52/106/242-RU, etc.) to the second STA. That is, the transmitting STA (e.g., AP) may transmit HE-STF, HE-LTF, and Data fields for the first STA through the first RU in one MU PPDU, and may transmit HE-STF, HE-LTF, and Data fields for the second STA through the second RU. 
     Information related to a layout of the RU may be signaled through HE-SIG-B. 
       FIG. 8  illustrates a structure of an HE-SIG-B field. 
     As illustrated, an HE-SIG-B field  810  includes a common field  820  and a user-specific field  830 . The common field  820  may include information commonly applied to all users (i.e., user STAs) which receive SIG-B. The user-specific field  830  may be called a user-specific control field. When the SIG-B is transferred to a plurality of users, the user-specific field  830  may be applied only any one of the plurality of users. 
     As illustrated in  FIG. 8 , the common field  820  and the user-specific field  830  may be separately encoded. 
     The common field  820  may include RU allocation information of N*8 bits. For example, the RU allocation information may include information related to a location of an RU. For example, when a 20 MHz channel is used as shown in  FIG. 5 , the RU allocation information may include information related to a specific frequency band to which a specific RU (26-RU/52-RU/106-RU) is arranged. 
     An example of a case in which the RU allocation information consists of  8  bits is as follows. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 8 bits indices 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 (B7 B6 B5 B4 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 Number 
               
               
                 B3 B2 B1 B0) 
                 #1 
                 #2 
                 #3 
                 #4 
                 #5 
                 #6 
                 #7 
                 #8 
                 #9 
                 of entries 
               
               
                   
               
             
            
               
                 00000000 
                 26 
                 26 
                 26 
                 26 
                 26 
                 26 
                 26 
                 26 
                 26 
                 1 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 00000001 
                 26 
                 26 
                 26 
                 26 
                 26 
                 26 
                 26 
                 52 
                 1 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 00000010 
                 26 
                 26 
                 26 
                 26 
                 26 
                 52 
                 26 
                 26 
                 1 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 00000011 
                 26 
                 26 
                 26 
                 26 
                 26 
                 52 
                 52 
                 1 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 00000100 
                 26 
                 26 
                 52 
                 26 
                 26 
                 26 
                 26 
                 26 
                 1 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 00000101 
                 26 
                 26 
                 52 
                 26 
                 26 
                 26 
                 52 
                 1 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 00000110 
                 26 
                 26 
                 52 
                 26 
                 52 
                 26 
                 26 
                 1 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 00000111 
                 26 
                 26 
                 52 
                 26 
                 52 
                 52 
                 1 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 00001000 
                 52 
                 26 
                 26 
                 26 
                 26 
                 26 
                 26 
                 26 
                 1 
               
               
                   
               
            
           
         
       
     
     As shown the example of  FIG. 5 , up to nine 26-RUs may be allocated to the 20 MHz channel. When the RU allocation information of the common field  820  is set to “00000000” as shown in Table 1, the nine 26-RUs may be allocated to a corresponding channel (i.e., 20 MHz). In addition, when the RU allocation information of the common field  820  is set to “00000001” as shown in Table 1, seven 26-RUs and one 52-RU are arranged in a corresponding channel That is, in the example of  FIG. 5 , the 52-RU may be allocated to the rightmost side, and the seven 26-RUs may be allocated to the left thereof. 
     The example of Table 1 shows only some of RU locations capable of displaying the RU allocation information. 
     For example, the RU allocation information may include an example of Table 2 below. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 8 bits indices 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 (B7 B6 B5 B4 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 Number 
               
               
                 B3 B2 B1 B0) 
                 #1 
                 #2 
                 #3 
                 #4 
                 #5 
                 #6 
                 #7 
                 #8 
                 #9 
                 of entries 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 01000 y     2     y     1     y     0     
                 106 
                 26 
                 26 
                 26 
                 26 
                 26 
                 8 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 01001 y     2     y     1     y     0     
                 106 
                 26 
                 26 
                 26 
                 52 
                 8 
               
               
                   
               
            
           
         
       
     
     “01000y2y1y0” relates to an example in which a 106-RU is allocated to the leftmost side of the 20 MHz channel, and five 26-RUs are allocated to the right side thereof. In this case, a plurality of STAs (e.g., user-STAs) may be allocated to the 106-RU, based on a MU-MIMO scheme. Specifically, up to 8 STAs (e.g., user-STAs) may be allocated to the 106-RU, and the number of STAs (e.g., user-STAs) allocated to the 106-RU is determined based on 3-bit information (y2y1y0). For example, when the 3-bit information (y2y1y0) is set to N, the number of STAs (e.g., user-STAs) allocated to the 106-RU based on the MU-MIMO scheme may be N+1. 
     In general, a plurality of STAs (e.g., user STAs) different from each other may be allocated to a plurality of RUs. However, the plurality of STAs (e.g., user STAs) may be allocated to one or more RUs having at least a specific size (e.g., 106 subcarriers), based on the MU-MIMO scheme. 
     As shown in  FIG. 8 , the user-specific field  830  may include a plurality of user fields. As described above, the number of STAs (e.g., user STAs) allocated to a specific channel may be determined based on the RU allocation information of the common field  820 . For example, when the RU allocation information of the common field  820  is “00000000”, one user STA may be allocated to each of nine 26-RUs (e.g., nine user STAs may be allocated). That is, up to 9 user STAs may be allocated to a specific channel through an OFDMA scheme. In other words, up to 9 user STAs may be allocated to a specific channel through a non-MU-MIMO scheme. 
     For example, when RU allocation is set to “01000y2y1y0”, a plurality of STAs may be allocated to the 106-RU arranged at the leftmost side through the MU-MIMO scheme, and five user STAs may be allocated to five 26-RUs arranged to the right side thereof through the non-MU MIMO scheme. This case is specified through an example of  FIG. 9 . 
       FIG. 9  illustrates an example in which a plurality of user STAs are allocated to the same RU through a MU-MIMO scheme. 
     For example, when RU allocation is set to “01000010” as shown in  FIG. 9 , a 106-RU may be allocated to the leftmost side of a specific channel, and five 26-RUs may be allocated to the right side thereof. In addition, three user STAs may be allocated to the 106-RU through the MU-MIMO scheme. As a result, since eight user STAs are allocated, the user-specific field  830  of HE-SIG-B may include eight user fields. 
     The eight user fields may be expressed in the order shown in  FIG. 9 . In addition, as shown in  FIG. 8 , two user fields may be implemented with one user block field. 
     The user fields shown in  FIG. 8  and  FIG. 9  may be configured based on two formats. That is, a user field related to a MU-MIMO scheme may be configured in a first format, and a user field related to a non-MIMO scheme may be configured in a second format. Referring to the example of  FIG. 9 , a user field  1  to a user field  3  may be based on the first format, and a user field  4  to a user field  8  may be based on the second format. The first format or the second format may include bit information of the same length (e.g., 21 bits). 
     Each user field may have the same size (e.g., 21 bits). For example, the user field of the first format (the first of the MU-MIMO scheme) may be configured as follows. 
     For example, a first bit (i.e., B 0 -B 10 ) in the user field (i.e., 21 bits) may include identification information (e.g., STA-ID, partial AID, etc.) of a user STA to which a corresponding user field is allocated. In addition, a second bit (i.e., B 11 -B 14 ) in the user field (i.e., 21 bits) may include information related to a spatial configuration. Specifically, an example of the second bit (i.e., B 11 -B 14 ) may be as shown in Table 3 and Table 4 below. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 Total 
                 Number 
               
               
                 N user   
                 B3 . . . B0 
                 [1] 
                 [2] 
                 [3] 
                 [4] 
                 [5] 
                 [6] 
                 [7] 
                 [8] 
                 N STS   
                 of entries 
               
               
                   
               
             
            
               
                 2 
                 0000-0011 
                 1-4 
                 1 
                   
                   
                   
                   
                   
                   
                 2-5 
                 10 
               
               
                   
                 0100-0110 
                 2-4 
                 2 
                   
                   
                   
                   
                   
                   
                 4-6 
               
               
                   
                 0111-1000 
                 3-4 
                 3 
                   
                   
                   
                   
                   
                   
                 6-7 
               
               
                   
                 1001 
                 4 
                 4 
                   
                   
                   
                   
                   
                   
                 8 
               
               
                 3 
                 0000-0011 
                 1-4 
                 1 
                 1 
                   
                   
                   
                   
                   
                 3-6 
                 13 
               
               
                   
                 0100-0110 
                 2-4 
                 2 
                 1 
                   
                   
                   
                   
                   
                 5-7 
               
               
                   
                 0111-1000 
                 3-4 
                 3 
                 1 
                   
                   
                   
                   
                   
                 7-8 
               
               
                   
                 1001-1011 
                 2-4 
                 2 
                 2 
                   
                   
                   
                   
                   
                 6-8 
               
               
                   
                 1100 
                 3 
                 3 
                 2 
                   
                   
                   
                   
                   
                 8 
               
               
                 4 
                 0000-0011 
                 1-4 
                 1 
                 1 
                 1 
                   
                   
                   
                   
                 4-7 
                 11 
               
               
                   
                 0100-0110 
                 2-4 
                 2 
                 1 
                 1 
                   
                   
                   
                   
                 6-8 
               
               
                   
                 0111 
                 3 
                 3 
                 1 
                 1 
                   
                   
                   
                   
                 8 
               
               
                   
                 1000-1001 
                 2-3 
                 2 
                 2 
                 1 
                   
                   
                   
                   
                 7-8 
               
               
                   
                 1010 
                 2 
                 2 
                 2 
                 2 
                   
                   
                   
                   
                 8 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                   
                   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 N STS   
                 Total 
                 Number 
               
               
                 N user   
                 B3 . . . B0 
                 [1] 
                 [2] 
                 [3] 
                 [4] 
                 [5] 
                 [6] 
                 [7] 
                 [8] 
                 N STS   
                 of entries 
               
               
                   
               
             
            
               
                 5 
                 0000-0011 
                 1-4 
                 1 
                 1 
                 1 
                 1 
                   
                   
                   
                 5-8 
                 7 
               
               
                   
                 0100-0101 
                 2-3 
                 2 
                 1 
                 1 
                 1 
                   
                   
                   
                 7-8 
               
               
                   
                 0110 
                 2 
                 2 
                 2 
                 1 
                 1 
                   
                   
                   
                 8 
               
               
                 6 
                 0000-0010 
                 1-3 
                 1 
                 1 
                 1 
                 1 
                 1 
                   
                   
                 6-8 
                 4 
               
               
                   
                 0011 
                 2 
                 2 
                 1 
                 1 
                 1 
                 1 
                   
                   
                 8 
               
               
                 7 
                 0000-0001 
                 1-2 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                   
                 7-8 
                 2 
               
               
                 8 
                 0000 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 8 
                 1 
               
               
                   
               
            
           
         
       
     
     As shown in Table 3 and/or Table 4, the second bit (e.g., B 11 -B 14 ) may include information related to the number of spatial streams allocated to the plurality of user STAs which are allocated based on the MU-MIMO scheme. For example, when three user STAs are allocated to the 106-RU based on the MU-MIMO scheme as shown in  FIG. 9 , N_user is set to “3”. Therefore, values of N_STS[1], N_STS[2], and N_STS[3] may be determined as shown in Table 3. For example, when a value of the second bit (B 11 -B 14 ) is “0011”, it may be set to N_STS[1]=4, N_STS[2]=1, N_STS[3]=1. That is, in the example of  FIG. 9 , four spatial streams may be allocated to the user field  1 , one spatial stream may be allocated to the user field  1 , and one spatial stream may be allocated to the user field  3 . 
     As shown in the example of Table 3 and/or Table 4, information (i.e., the second bit, B 11 -B 14 ) related to the number of spatial streams for the user STA may consist of 4 bits. In addition, the information (i.e., the second bit, B 11 -B 14 ) on the number of spatial streams for the user STA may support up to eight spatial streams. In addition, the information (i.e., the second bit, B 11 -B 14 ) on the number of spatial streams for the user STA may support up to four spatial streams for one user STA. 
     In addition, a third bit (i.e., B 15 - 18 ) in the user field (i.e., 21 bits) may include modulation and coding scheme (MCS) information. The MCS information may be applied to a data field in a PPDU including corresponding SIG-B. 
     An MCS, MCS information, an MCS index, an MCS field, or the like used in the present specification may be indicated by an index value. For example, the MCS information may be indicated by an index 0 to an index 11. The MCS information may include information related to a constellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, etc.) and information related to a coding rate (e.g., ½, ⅔, ¾, ⅚e, etc.). Information related to a channel coding type (e.g., LCC or LDPC) may be excluded in the MCS information. 
     In addition, a fourth bit (i.e., B 19 ) in the user field (i.e., 21 bits) may be a reserved field. 
     In addition, a fifth bit (i.e., B 20 ) in the user field (i.e., 21 bits) may include information related to a coding type (e.g., BCC or LDPC). That is, the fifth bit (i.e., B 20 ) may include information related to a type (e.g., BCC or LDPC) of channel coding applied to the data field in the PPDU including the corresponding SIG-B. 
     The aforementioned example relates to the user field of the first format (the format of the MU-MIMO scheme). An example of the user field of the second format (the format of the non-MU-MIMO scheme) is as follows. 
     A first bit (e.g., B 0 -B 10 ) in the user field of the second format may include identification information of a user STA. In addition, a second bit (e.g., B 11 -B 13 ) in the user field of the second format may include information related to the number of spatial streams applied to a corresponding RU. In addition, a third bit (e.g., B 14 ) in the user field of the second format may include information related to whether a beamforming steering matrix is applied. A fourth bit (e.g., B 15 -B 18 ) in the user field of the second format may include modulation and coding scheme (MCS) information. In addition, a fifth bit (e.g., B 19 ) in the user field of the second format may include information related to whether dual carrier modulation (DCM) is applied. In addition, a sixth bit (i.e., B 20 ) in the user field of the second format may include information related to a coding type (e.g., BCC or LDPC). 
       FIG. 10  illustrates an operation based on UL-MU. As illustrated, a transmitting STA (e.g., an AP) may perform channel access through contending (e.g., a backoff operation), and may transmit a trigger frame  1030 . That is, the transmitting STA may transmit a PPDU including the trigger frame  1030 . Upon receiving the PPDU including the trigger frame, a trigger-based (TB) PPDU is transmitted after a delay corresponding to SIFS. 
     TB PPDUs  1041  and  1042  may be transmitted at the same time period, and may be transmitted from a plurality of STAs (e.g., user STAs) having AIDs indicated in the trigger frame  1030 . An ACK frame  1050  for the TB PPDU may be implemented in various forms. 
     A specific feature of the trigger frame is described with reference to  FIG. 11  to  FIG. 13 . Even if UL-MU communication is used, an orthogonal frequency division multiple access (OFDMA) scheme or a MU MIMO scheme may be used, and the OFDMA and MU-MIMO schemes may be simultaneously used. 
       FIG. 11  illustrates an example of a trigger frame. The trigger frame of  FIG. 11  allocates a resource for uplink multiple-user (MU) transmission, and may be transmitted, for example, from an AP. The trigger frame may be configured of a MAC frame, and may be included in a PPDU. 
     Each field shown in  FIG. 11  may be partially omitted, and another field may be added. In addition, a length of each field may be changed to be different from that shown in the figure. 
     A frame control field  1110  of  FIG. 11  may include information related to a MAC protocol version and extra additional control information. A duration field  1120  may include time information for NAV configuration or information related to an identifier (e.g., AID) of a STA. 
     In addition, an RA field  1130  may include address information of a receiving STA of a corresponding trigger frame, and may be optionally omitted. A TA field  1140  may include address information of a STA (e.g., an AP) which transmits the corresponding trigger frame. A common information field  1150  includes common control information applied to the receiving STA which receives the corresponding trigger frame. For example, a field indicating a length of an L-SIG field of an uplink PPDU transmitted in response to the corresponding trigger frame or information for controlling content of a SIG-A field (i.e., HE-SIG-A field) of the uplink PPDU transmitted in response to the corresponding trigger frame may be included. In addition, as common control information, information related to a length of a CP of the uplink PPDU transmitted in response to the corresponding trigger frame or information related to a length of an LTF field may be included. 
     In addition, per user information fields  1160 # 1  to  1160 #N corresponding to the number of receiving STAs which receive the trigger frame of  FIG. 11  are preferably included. The per user information field may also be called an “allocation field”. 
     In addition, the trigger frame of  FIG. 11  may include a padding field  1170  and a frame check sequence field  1180 . 
     Each of the per user information fields  1160 # 1  to  1160 #N shown in  FIG. 11  may include a plurality of subfields. 
       FIG. 12  illustrates an example of a common information field of a trigger frame. A subfield of  FIG. 12  may be partially omitted, and an extra subfield may be added. In addition, a length of each subfield illustrated may be changed. 
     A length field  1210  illustrated has the same value as a length field of an L-SIG field of an uplink PPDU transmitted in response to a corresponding trigger frame, and a length field of the L-SIG field of the uplink PPDU indicates a length of the uplink PPDU. As a result, the length field  1210  of the trigger frame may be used to indicate the length of the corresponding uplink PPDU. 
     In addition, a cascade identifier field  1220  indicates whether a cascade operation is performed. The cascade operation implies that downlink MU transmission and uplink MU transmission are performed together in the same TXOP. That is, it implies that downlink MU transmission is performed and thereafter uplink MU transmission is performed after a pre-set time (e.g., SIFS). During the cascade operation, only one transmitting device (e.g., AP) may perform downlink communication, and a plurality of transmitting devices (e.g., non-APs) may perform uplink communication. 
     A CS request field  1230  indicates whether a wireless medium state or a NAV or the like is necessarily considered in a situation where a receiving device which has received a corresponding trigger frame transmits a corresponding uplink PPDU. 
     An HE-SIG-A information field  1240  may include information for controlling content of a SIG-A field (i.e., HE-SIG-A field) of the uplink PPDU in response to the corresponding trigger frame. 
     A CP and LTF type field  1250  may include information related to a CP length and LTF length of the uplink PPDU transmitted in response to the corresponding trigger frame. A trigger type field  1260  may indicate a purpose of using the corresponding trigger frame, for example, typical triggering, triggering for beamforming, a request for block ACK/NACK, or the like. 
     It may be assumed that the trigger type field  1260  of the trigger frame in the present specification indicates a trigger frame of a basic type for typical triggering. For example, the trigger frame of the basic type may be referred to as a basic trigger frame. 
       FIG. 13  illustrates an example of a subfield included in a per user information field. A user information field  1300  of  FIG. 13  may be understood as any one of the per user information fields  1160 # 1  to  1160 #N mentioned above with reference to  FIG. 11 . A subfield included in the user information field  1300  of  FIG. 13  may be partially omitted, and an extra subfield may be added. In addition, a length of each subfield illustrated may be changed. 
     A user identifier field  1310  of  FIG. 13  indicates an identifier of a STA (i.e., receiving STA) corresponding to per user information. An example of the identifier may be the entirety or part of an association identifier (AID) value of the receiving STA. 
     In addition, an RU allocation field  1320  may be included. That is, when the receiving STA identified through the user identifier field  1310  transmits a TB PPDU in response to the trigger frame, the TB PPDU is transmitted through an RU indicated by the RU allocation field  1320 . In this case, the RU indicated by the RU allocation field  1320  may be an RU shown in  FIG. 5 ,  FIG. 6 , and  FIG. 7 . 
     The subfield of  FIG. 13  may include a coding type field  1330 . The coding type field  1330  may indicate a coding type of the TB PPDU. For example, when BCC coding is applied to the TB PPDU, the coding type field  1330  may be set to ‘1’, and when LDPC coding is applied, the coding type field  1330  may be set to ‘0’. 
     In addition, the subfield of  FIG. 13  may include an MCS field  1340 . The MCS field  1340  may indicate an MCS scheme applied to the TB PPDU. For example, when BCC coding is applied to the TB PPDU, the coding type field  1330  may be set to ‘1’, and when LDPC coding is applied, the coding type field  1330  may be set to ‘0’. 
     Hereinafter, a UL OFDMA-based random access (UORA) scheme will be described. 
       FIG. 14  describes a technical feature of the UORA scheme. 
     A transmitting STA (e.g., an AP) may allocate six RU resources through a trigger frame as shown in  FIG. 14 . Specifically, the AP may allocate a 1st RU resource (AID 0, RU 1), a 2nd RU resource (AID 0, RU 2), a 3rd RU resource (AID 0, RU 3), a 4th RU resource (AID 2045, RU 4), a 5th RU resource (AID 2045, RU 5), and a 6th RU resource (AID 3, RU 6). Information related to the AID 0, AID 3, or AID 2045 may be included, for example, in the user identifier field  1310  of  FIG. 13 . Information related to the RU 1 to RU 6 may be included, for example, in the RU allocation field  1320  of  FIG. 13 . AID=0 may imply a UORA resource for an associated STA, and AID=2045 may imply a UORA resource for an un-associated STA. Accordingly, the 1st to 3rd RU resources of  FIG. 14  may be used as a UORA resource for the associated STA, the 4th and 5th RU resources of  FIG. 14  may be used as a UORA resource for the un-associated STA, and the 6th RU resource of  FIG. 14  may be used as a typical resource for UL MU. 
     In the example of  FIG. 14 , an OFDMA random access backoff (OBO) of a STA1 is decreased to 0, and the STA1 randomly selects the 2nd RU resource (AID 0, RU 2). In addition, since an OBO counter of a STA2/3 is greater than 0, an uplink resource is not allocated to the STA2/3. In addition, regarding a STA4 in  FIG. 14 , since an AID (e.g., AID=3) of the STA4 is included in a trigger frame, a resource of the RU 6 is allocated without backoff. 
     Specifically, since the STA1 of  FIG. 14  is an associated STA, the total number of eligible RA RUs for the STA1 is 3 (RU 1, RU 2, and RU 3), and thus the STA1 decreases an OBO counter by 3 so that the OBO counter becomes 0. In addition, since the STA2 of FIG.  14  is an associated STA, the total number of eligible RA RUs for the STA2 is 3 (RU 1, RU 2, and RU 3), and thus the STA2 decreases the OBO counter by 3 but the OBO counter is greater than 0. In addition, since the STA3 of  FIG. 14  is an un-associated STA, the total number of eligible RA RUs for the STA3 is 2 (RU 4, RU 5), and thus the STA3 decreases the OBO counter by 2 but the OBO counter is greater than 0. 
       FIG. 15  illustrates an example of a channel used/supported/defined within a 2.4 GHz band. 
     The 2.4 GHz band may be called in other terms such as a first band. In addition, the 2.4 GHz band may imply a frequency domain in which channels of which a center frequency is close to 2.4 GHz (e.g., channels of which a center frequency is located within 2.4 to 2.5 GHz) are used/supported/defined. 
     A plurality of 20 MHz channels may be included in the 2.4 GHz band. 20 MHz within the 2.4 GHz may have a plurality of channel indices (e.g., an index 1 to an index 14). For example, a center frequency of a 20 MHz channel to which a channel index 1 is allocated may be 2.412 GHz, a center frequency of a 20 MHz channel to which a channel index 2 is allocated may be 2.417 GHz, and a center frequency of a 20 MHz channel to which a channel index N is allocated may be (2.407+0.005*N) GHz. The channel index may be called in various terms such as a channel number or the like. Specific numerical values of the channel index and center frequency may be changed. 
       FIG. 15  exemplifies 4 channels within a 2.4 GHz band. Each of 1st to 4th frequency domains  1510  to  1540  shown herein may include one channel For example, the 1st frequency domain  1510  may include a channel 1 (a 20 MHz channel having an index 1). In this case, a center frequency of the channel 1 may be set to 2412 MHz. The 2nd frequency domain  1520  may include a channel 6. In this case, a center frequency of the channel 6 may be set to 2437 MHz. The 3rd frequency domain  1530  may include a channel 11. In this case, a center frequency of the channel 11 may be set to 2462 MHz. The 4th frequency domain  1540  may include a channel 14. In this case, a center frequency of the channel 14 may be set to 2484 MHz. 
       FIG. 16  illustrates an example of a channel used/supported/defined within a 5 GHz band. 
     The 5 GHz band may be called in other terms such as a second band or the like. The 5 GHz band may imply a frequency domain in which channels of which a center frequency is greater than or equal to 5 GHz and less than 6 GHz (or less than 5.9 GHz) are used/supported/defined. Alternatively, the 5 GHz band may include a plurality of channels between 4.5 GHz and 5.5 GHz. A specific numerical value shown in  FIG. 16  may be changed. 
     A plurality of channels within the 5 GHz band include an unlicensed national information infrastructure (UNII)-1, a UNII-2, a UNII-3, and an ISM. The INII-1 may be called UNII Low. The UNII-2 may include a frequency domain called UNII Mid and UNII-2Extended. The UNII-3 may be called UNII-Upper. 
     A plurality of channels may be configured within the 5 GHz band, and a bandwidth of each channel may be variously set to, for example, 20 MHz, 40 MHz, 80 MHz, 160 MHz, or the like. For example, 5170 MHz to 5330 MHz frequency domains/ranges within the UNII-1 and UNII-2 may be divided into eight 20 MHz channels. The 5170 MHz to 5330 MHz frequency domains/ranges may be divided into four channels through a 40 MHz frequency domain. The 5170 MHz to 5330 MHz frequency domains/ranges may be divided into two channels through an 80 MHz frequency domain. Alternatively, the 5170 MHz to 5330 MHz frequency domains/ranges may be divided into one channel through a 160 MHz frequency domain. 
       FIG. 17  illustrates an example of a channel used/supported/defined within a 6 GHz band. 
     The 6 GHz band may be called in other terms such as a third band or the like. The 6 GHz band may imply a frequency domain in which channels of which a center frequency is greater than or equal to 5.9 GHz are used/supported/defined. A specific numerical value shown in  FIG. 17  may be changed. 
     For example, the 20 MHz channel of  FIG. 17  may be defined starting from 5.940 GHz. Specifically, among 20 MHz channels of  FIG. 17 , the leftmost channel may have an index 1 (or a channel index, a channel number, etc.), and 5.945 GHz may be assigned as a center frequency. That is, a center frequency of a channel of an index N may be determined as (5.940+0.005*N) GHz. 
     Accordingly, an index (or channel number) of the 2 MHz channel of  FIG. 17  may be 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 129, 133, 137, 141, 145, 149, 153, 157, 161, 165, 169, 173, 177, 181, 185, 189, 193, 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. In addition, according to the aforementioned (5.940+0.005*N)GHz rule, an index of the 40 MHz channel of  FIG. 17  may be 3, 11, 19, 27, 35, 43, 51, 59, 67, 75, 83, 91, 99, 107, 115, 123, 131, 139, 147, 155, 163, 171, 179, 187, 195, 203, 211, 219, 227. 
     Although 20, 40, 80, and 160 MHz channels are illustrated in the example of  FIG. 17 , a 240 MHz channel or a 320 MHz channel may be additionally added. 
     Hereinafter, a PPDU transmitted/received in a STA of the present specification will be described. 
       FIG. 18  illustrates an example of a PPDU used in the present specification. 
     The PPDU 1800 depicted in  FIG. 18  may be referred to as various terms such as an EHT PPDU, a TX PPDU, an RX PPDU, a first type or N-th type PPDU, or the like. In addition, the EHT PPDU may be used in an EHT system and/or a new WLAN system enhanced from the EHT system. 
     The subfields 1801 to 1810 depicted in  FIG. 18  may be referred to as various terms. For example, a SIG A field 1805 may be referred to an EHT-SIG-A field, a SIG B field 1806 may be referred to an EHT-SIG-B, a STF field 1807 may be referred to an EHT-STF field, and an LTF field 1808 may be referred to an EHT-LTF. 
     The subcarrier spacing of the L-LTF, L-STF, L-SIG, and RL-SIG fields 1801, 1802, 1803, and 1804 of  FIG. 18  can be set to 312.5 kHz, and the subcarrier spacing of the STF, LTF, and Data fields 1807, 1808, and 1809 of  FIG. 18  can be set to 78.125 kHz. That is, the subcarrier index of the L-LTF, L-STF, L-SIG, and RL-SIG fields 1801, 1802, 1803, and 1804 can be expressed in unit of 312.5 kHz, and the subcarrier index of the STF, LTF, and Data fields 1807, 1808, and 1809 can be expressed in unit of 78.125 kHz. 
     The SIG A and/or SIG B fields of  FIG. 18  may include additional fields (e.g., a SIG C field or one control symbol, etc.). The subcarrier spacing of all or part of the SIG A and SIG B fields may be set to 312.5 kHz, and the subcarrier spacing of all or part of newly-defined SIG field(s) may be set to 312.5 kHz. Meanwhile, the subcarrier spacing for a part of the newly-defined SIG field(s) may be set to a pre-defined value (e.g., 312.5 kHz or 78.125 kHz). 
     In the PPDU of  FIG. 18 , the L-LTF and the L-STF may be the same as conventional L-LTF and L-STF fields. 
     The L-SIG field of FIG. 18 may include, for example, bit information of 24 bits. For example, the 24-bit information may include a rate field of 4 bits, a reserved bit of 1 bit, a length field of 12 bits, a parity bit of 1 bit, and a tail bit of 6 bits. For example, the length field of 12 bits may include information related to the number of octets of a corresponding Physical Service Data Unit (PSDU). For example, the length field of 12 bits may be determined based on a type of the PPDU. For example, when the PPDU is a non-HT, HT, VHT PPDU or an EHT PPDU, a value of the length field may be determined as a multiple of 3. For example, when the PPDU is an HE PPDU, the value of the length field may be determined as “a multiple of 3”+1 or “a multiple of 3”+2. In other words, for the non-HT, HT, VHT PPDI or the EHT PPDU, the value of the length field may be determined as a multiple of 3, and for the HE PPDU, the value of the length field may be determined as “a multiple of 3”+1 or “a multiple of 3”+2. 
     For example, the transmitting STA may apply BCC encoding based on a ½ coding rate to the 24-bit information of the L-SIG field. Thereafter, the transmitting STA may obtain a BCC coding bit of 48 bits. BPSK modulation may be applied to the 48-bit coding bit, thereby generating 48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols to positions except for a pilot subcarrier {subcarrier index −21, −7, +7, +21} and a DC subcarrier {subcarrier index 0}. As a result, the 48 BPSK symbols may be mapped to subcarrier indices −26 to −22, −20 to −8, −6 to −1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA may additionally map a signal of {−1, −1, −1, 1} to a subcarrier index {−28, −27, +27, +28}. The aforementioned signal may be used for channel estimation on a frequency domain corresponding to {−28, −27, +27, +28}. 
     The transmitting STA may generate an RL-SIG which is identical to the L-SIG. BPSK modulation may be applied to the RL-SIG. The receiving STA may figure out that the RX PPDU is the HE PPDU or the EHT PPDU, based on the presence of the RL-SIG. 
     After the RL-SIG of  FIG. 18 , for example, EHT-SIG-A or one control symbol may be inserted. A symbol contiguous to the RL-SIG (i.e., EHT-SIG-A or one control symbol) may include 26 bit information and may further include information for identifying the type of the EHT PPDU. For example, when the EHT PPDU is classified into various types (e.g., an EHT PPDU supporting an SU mode, an EHT PPDU supporting a MU mode, an EHT PPDU related to the Trigger Frame, an EHT PPDU related to an Extended Range transmission, etc.), Information related to the type of the EHT PPDU may be included in a symbol contiguous to the RL-SIG. 
     A symbol contiguous to the RL-SIG may include, for example, information related to the length of the TXOP and information related to the BSS color ID. For example, the SIG-A field may be contiguous to the symbol contiguous to the RL-SIG (e.g., one control symbol). Alternatively, a symbol contiguous to the RL-SIG may be the SIG-A field. 
     For example, the SIG-A field may include 1) a DL/UL indicator, 2) a BSS color field which is an identifier of a BSS, 3) a field including information related to the remaining time of a current TXOP duration, 4) a bandwidth field including information related to the bandwidth, 5) a field including information related to an MCS scheme applied to an HE-SIG B, 6) a field including information related to whether a dual subcarrier modulation (DCM) scheme is applied to the HE-SIG B, 7) a field including information related to the number of symbols used for the HE-SIG B, 8) a field including information related to whether the HE-SIG B is generated over the entire band, 9) a field including information related to the type of the LTF/STF,  10 ) a field indicating the length of the HE-LTF and a CP length. 
     The SIG-B of  FIG. 18  may include the technical features of HE-SIG-B shown in the example of  FIGS. 8 to 9  as it is. 
     An STF of  FIG. 18  may be used to improve automatic gain control estimation in a multiple input multiple output (MIMO) environment or an OFDMA environment. An LTF of  FIG. 18  may be used to estimate a channel in the MIMO environment or the OFDMA environment. 
     The EHT-STF of  FIG. 18  may be set in various types. For example, a first type of STF (e.g., 1x STF) may be generated based on a first type STF sequence in which a non-zero coefficient is arranged with an interval of 16 subcarriers. An STF signal generated based on the first type STF sequence may have a period of 0.8 μs, and a periodicity signal of 0.8 μs may be repeated 5 times to become a first type STF having a length of 4 μs. For example, a second type of STF (e.g., 2x STF) may be generated based on a second type STF sequence in which a non-zero coefficient is arranged with an interval of 8 subcarriers. An STF signal generated based on the second type STF sequence may have a period of 1.6 μs, and a periodicity signal of 1.6 μs may be repeated 5 times to become a second type STF having a length of 8 μs. For example, a third type of STF (e.g., 4x STF) may be generated based on a third type STF sequence in which a non-zero coefficient is arranged with an interval of 4 subcarriers. An STF signal generated based on the third type STF sequence may have a period of 3.2 μs, and a periodicity signal of 3.2 μs may be repeated 5 times to become a second type STF having a length of 16 μs. Only some of the first to third type EHT-STF sequences may be used. In addition, the EHT-LTF field may also have first, second, and third types (i.e., 1x, 2x, 4x LTF). For example, the first/second/third type LTF field may be generated based on an LTF sequence in which a non-zero coefficient is arranged with an interval of 4/2/1 subcarriers. The first/second/third type LTF may have a time length of 3.2/6.4/12.8 μs. In addition, Guard Intervals (GIs) with various lengths (e.g., 0.8/1/6/3.2 μs) may be applied to the first/second/third type LTF. 
     Information related to the type of STF and/or LTF (including information related to GI applied to the LTF) may be included in the SIG A field and/or the SIG B field of  FIG. 18 . 
     The PPDU of  FIG. 18  may support various bandwidths. For example, the PPDU of  FIG. 18  may have a bandwidth of 20/40/80/160/240/320 MHz. For example, at least one field (e.g., STF, LTF, data) of  FIG. 18  may be configured based on RUs illustrated in  FIGS. 5 to 7 , and the like. For example, when there is one receiving STA of the PPDU of  FIG. 18 , all fields of the PPDU of  FIG. 18  may occupy the entire bandwidth. For example, when there are multiple receiving STAs of the PPDU of  FIG. 18  (i.e., when MU PPDU is used), some fields (e.g., STF, LTF, data) of  FIG. 18  may be configured based on the RUs shown in  FIGS. 5 to 7 . For example, the STF, LTF, and data fields for the first receiving STA of the PPDU may be transmitted/received through a first RU, and the STF, LTF, and data fields for the second receiving STA of the PPDU may be transmitted/received through a second RU. In this case, the locations/positions of the first and second RUs may be determined based on  FIGS. 5 to 7 , and the like. 
     The PPDU of  FIG. 18  may be determined (or identified) as an EHT PPDU based on the following method. 
     A receiving STA may determine a type of an RX PPDU as the EHT PPDU, based on the following aspect. For example, the RX PPDU may be determined as the EHT PPDU: 1) when a first symbol after an L-LTF signal of the RX PPDU is a BPSK symbol; 2) when RL-SIG in which the L-SIG of the RX PPDU is repeated is detected; and 3) when a result of applying “module  3 ” to a value of a length field of the L-SIG of the RX PPDU is detected as “0”. When the RX PPDU is determined as the EHT PPDU, the receiving STA may detect a type of the EHT PPDU (e.g., an SU/MU/Trigger-based/Extended Range type), based on bit information included in a symbol after the RL-SIG of  FIG. 18 . In other words, the receiving STA may determine the RX PPDU as the EHT PPDU, based on: 1) a first symbol after an L-LTF signal, which is a BPSK symbol; 2) RL-SIG contiguous to the L-SIG field and identical to L-SIG; 3) L-SIG including a length field in which a result of applying “modulo 3” is set to “0”; and 4) a 3-bit PHY version identifier of the aforementioned U-SIG (e.g., a PHY version identifier having a first value). 
     For example, the receiving STA may determine the type of the RX PPDU as the EHT PPDU, based on the following aspect. For example, the RX PPDU may be determined as the HE PPDU: 1) when a first symbol after an L-LTF signal is a BPSK symbol; 2) when RL-SIG in which the L-SIG is repeated is detected; and 3) when a result of applying “module 3” to a value of a length field of the L-SIG is detected as “1” or “2”. 
     For example, the receiving STA may determine the type of the RX PPDU as a non-HT, HT, and VHT PPDU, based on the following aspect. For example, the RX PPDU may be determined as the non-HT, HT, and VHT PPDU: 1) when a first symbol after an L-LTF signal is a BPSK symbol; and 2) when RL-SIG in which L-SIG is repeated is not detected. In addition, even if the receiving STA detects that the RL-SIG is repeated, when a result of applying “modulo 3” to the length value of the L-SIG is detected as “0”, the RX PPDU may be determined as the non-HT, HT, and VHT PPDU. 
     In the following example, a signal represented as a (TX/RX/UL/DL) signal, a (TX/RX/UL/DL) frame, a (TX/RX/UL/DL) packet, a (TX/RX/UL/DL) data unit, (TX/RX/UL/DL) data, or the like may be a signal transmitted/received based on the PPDU of  FIG. 18 . The PPDU of  FIG. 18  may be used to transmit/receive frames of various types. For example, the PPDU of  FIG. 18  may be used for a control frame. An example of the control frame may include a request to send (RTS), a clear to send (CTS), a power save-poll (PS-poll), BlockACKReq, BlockAck, a null data packet (NDP) announcement, and a trigger frame. For example, the PPDU of  FIG. 18  may be used for a management frame. An example of the management frame may include a beacon frame, a (re-)association request frame, a (re-)association response frame, a probe request frame, and a probe response frame. For example, the PPDU of  FIG. 18  may be used for a data frame. For example, the PPDU of  FIG. 18  may be used to simultaneously transmit at least two or more of the control frame, the management frame, and the data frame. 
       FIG. 19  illustrates an example of a modified transmission device and/or receiving device of the present specification. 
     Each device/STA of the sub-figure ( a )/( b ) of  FIG. 1  may be modified as shown in  FIG. 19 . A transceiver  630  of  FIG. 19  may be identical to the transceivers  113  and  123  of  FIG. 1 . The transceiver  630  of  FIG. 19  may include a receiver and a transmitter. 
     A processor  610  of  FIG. 19  may be identical to the processors  111  and  121  of  FIG. 1 . Alternatively, the processor  610  of  FIG. 19  may be identical to the processing chips  114  and  124  of  FIG. 1 . 
     A memory  620  of  FIG. 19  may be identical to the memories  112  and  122  of  FIG. 1 . Alternatively, the memory  620  of  FIG. 19  may be a separate external memory different from the memories  112  and  122  of  FIG. 1 . 
     Referring to  FIG. 19 , a power management module  611  manages power for the processor  610  and/or the transceiver  630 . A battery  612  supplies power to the power management module  611 . A display  613  outputs a result processed by the processor  610 . A keypad  614  receives inputs to be used by the processor  610 . The keypad  614  may be displayed on the display  613 . A SIM card  615  may be an integrated circuit which is used to securely store an international mobile subscriber identity (IMSI) and its related key, which are used to identify and authenticate subscribers on mobile telephony devices such as mobile phones and computers. 
     Referring to  FIG. 19 , a speaker  640  may output a result related to a sound processed by the processor  610 . A microphone  641  may receive an input related to a sound to be used by the processor  610 . 
       FIG. 20  shows a band plan of 5.9 GHz DSRC. 
     5.9 GHz DSRC is a short to medium range communications service that supports both public safety and private operations in roadside-to-vehicle and vehicle-to-vehicle communication environments. DSRC is devised as a complement to cellular communications by providing very high data transfer rates in situations where minimizing latency in the communication link and isolating relatively small communication zones are important. 
     Additionally, PHY and MAC protocols are based on the revision of IEEE 802.11p for wireless access in a vehicular environment (WAVE). 
     &lt;IEEE 802.11p&gt; 
     802.11p uses a PHY of  802 . 11   a  by performing  2   x  downclocking on the PHY. That is, 802.11p transmits a signal by using a 10 MHz bandwidth and not a 20 MHz bandwidth. The numerology comparing  802 . 11   a  to 802.11p is as follows. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                   
                 IEEE 802.11a 
                 IEEE 802.11p 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Symbol deration 
                 4 
                 us 
                 8 
                 us 
               
               
                   
                 Guard period 
                 0.8 
                 us 
                 1.6 
                 us 
               
               
                   
                 Subcarrier spacing 
                 312.5 
                 KHz 
                 156.25 
                 KHz 
               
            
           
           
               
               
               
               
            
               
                   
                 OFDM subcarrier 
                 52 
                 52 
               
               
                   
                 Number of pilot 
                 4 
                 4 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Default BW 
                 20 
                 MHz 
                 10 
                 MHz 
               
            
           
           
               
               
               
               
            
               
                   
                 Data rate (Mbps) 
                 6, 9, 12, 18, 
                 3, 4. 5, 6, 9, 
               
               
                   
                   
                 24, 36, 48, 54 Mbps 
                 12, 18, 24, 27 Mbps 
               
               
                   
                 Frequency band 
                 5 GHz ISM 
                 5.9 GHz dedicated 
               
               
                   
                   
               
            
           
         
       
     
     Channels of a DSRC band include a control channel and a service channel, and each channel is capable of performing data transmission at 3, 4.5, 6, 9, 12, 18, 24, and 27 Mbps. If an option channel (or optional channel) of 20 MHz exists, transmission at 6, 9, 12, 18, 24, 36, 48, and 54 Mbps may be performed. 6, 9, and 12 Mbps should be supported in all services and channels. And, in case of a control channel, although a preamble is 3 Mbps, the message itself is 6 Mbps. In case channels  174  and  176  and channels  180  and  182  are authorized by a frequency regulation organization, the channel sets may be channels  175  and  181  of 20 MHz, respectively. The remaining channel should be reserved for future usage. A short message or notification data, public safety alarm data, and so on, are broadcasted to all On Board Units (OBUs) through the control channel The control channel and the service channel have been isolated in order to maximize efficiency and quality of service and to reduce interference between services. 
     Channel number  178  is a control channel, which automatically performs search and receives notification or data transmission, warning messages, and so on, from a Road Side Unit (RSU). All data of the control channel should be transmitted within 200 ms and is repeated at a pre-defined cycle. In a control channel, public safety warnings have the highest priority over any other private messages. Private messages that are larger than 200 ms are transmitted through a service channel. 
     Private messages or long public safety messages, and so on, are transmitted through a service channel In order to prevent collision (or conflict), a scheme for detecting channel status (i.e., Carrier Sense Multiple Access (CSMA)) is used prior to the transmission. 
     Hereinafter, EDCA parameters in an Outside Context of BSS (OCB) mode will be defined. An OCB mode denotes a state where direct communication between nodes can be performed without any procedure of association with an AP. The following shows a basic EDCA parameter set for STA operations, in case dot11OCBActivated is true. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
               
                   
                   
                   
                   
                 TXOP 
               
               
                 AC 
                 CWmin 
                 CWmax 
                 AIFSN 
                 limit 
               
               
                   
               
             
            
               
                 AC_BK 
                 aCWmin 
                 aCWmax 
                 9 
                 0 
               
               
                 AC_BE 
                 aCWmin 
                 aCWmax 
                 6 
                 0 
               
               
                 AC_VI 
                 (aCWmin + 1)/2 − 1 
                 aCWmin 
                 3 
                 0 
               
               
                 AC_VO 
                 (aCWmin + 1)/4 − 1 
                 (aCWmin + 1)/2 − 1 
                 2 
                 0 
               
               
                   
               
            
           
         
       
     
     Characteristics of the OCB mode are as follows. 
     1. In a MAC header, To/From DS fields may be set to ‘0’. 
     2. Fields related to Address
         Individual or group destination MAC address may be used.   A BSSID field may be the same as a wildcard BSSID. (BSSID field=wildcard BSSID)   In a Data/Management frame, Address 1 may be an RA, Address 2 may be a TA, and Address 3 may be a wildcard BSSID.       

     3. An authentication process, an association process, or data confidentiality services of the IEEE 802.11 standard may not be used (or utilized). 
     4. A TXOP limit may be set to ‘0’. 
     5. Only a TC (TID) may be used. 
     6. STAs may not be required to synchronize to a common clock or use such mechanisms.
         STAs may maintain a timing synchronization function (TSF) timer for purposes other than synchronization       

     7. The STA may send Action frames, and, if the STA maintains a TSF Timer, the STA may transmit Timing Advertisement frames. 
     8. The STA may send control frames excluding subtype PS-Poll, CF-End, and CF-End +CFAck. 
     9. The STA may send data frames of subtype Data, Null, QoS Data, and QoS Null. 
     10. An STA having dot11OCBActivated that is equal to true should not join (or participate in) or start a BSS. 
     Hereinafter, for example, technical features capable of providing interoperability of a plurality of systems are proposed. For example, the plurality of systems may include a system (IEEE 802.11bd standard) proposed to improve throughput and support high speed for V2X (Vehicle-to-Everything) in the 5.9 GHz band and/or a DSRC system configured based on the existing IEEE 802.11p standard. 
     For smooth V2X support in the 5.9 GHz band, NGV technology is being developed in consideration of throughput improvement and high-speed support of the DSRC system.  FIGS. 21 to 22  show a frame format (hereinafter, NGV PPDU) according to the IEEE 802.11bd standard. 
     The NGV PPDU described below may include a preamble, a data field being contiguous to the preamble, and a midamble being contiguous to the data field. In addition, the NGV PPDU may include an additional data field being continuous to the midamble. The number of symbols (or periodicity) of the midamble in the NGV PPDU may be variously configured. For example, the preamble of the NGV PPDU may include L-STF, L-LTF, L-SIG, RL-SIG, NGV-SIG, RNGV-SIG, NGV-STF, and/or NGV-LTF. The NGV midamble may be configured in the same format as the NGV-LTF. The aforementioned L-SIG, RL-SIG, NGV-SIG, and/or RNGV-SIG may be referred to as L-SIG field, RL-SIG field, NGV-SIG field, and/or RNGV-SIG field, respectively. 
       FIG. 21  shows the format of an NGV PPDU for a 10 MHz transmission. 
     Referring to  FIG. 21 , for backward compatibility or interoperability with the IEEE 802.11p standard, the NGV PPDU  2100  may include a field (i.e., L-STF, L-LTF, and/or L-SIG) of a frame (hereinafter, 11p PPDU) being configured based on the IEEE 802.11p standard. For example, the NGV PPDU  2100  may include an L-STF  2110 , an L-LTF  2120 , or an L-SIG  2130 . Additionally, the NGV PPDU may include an RL-SIG  2140 , an NGV-SIG  2150 , an RNGV-SIG  2160 , an NGV-STF  2170 , an NGV-LTF  2180 , and/or an NGV Data  2190 . 
     The RL-SIG  2140  may be contiguous to the L-SIG  2130 . The RL-SIG  2140  may be a field in which the L-SIG  2130  is repeated. In other words, the RL-SIG  2140  may include the same information fields as the L-SIG  2130  and may be modulated (e.g., BPSK) in the same manner as the L-SIG  2130 . 
     The NGV-SIG  2150  may be related to transmission information. For example, the NGV-SIG  2150  may include transmission information. For example, the NGV-SIG  2150  may be 24-bit information. For example, the NGV-SIG  2150  includes information related to a physical layer (PHY) version, information related to a bandwidth, information related to MCS, information related to the number of spatial streams, information related to a midamble periodicity, information related to LTF format, information related to LDPC Extra OFDM Symbol, information related to CRC, and/or information related to a tail bit. BCC encoding based on a coding rate of ½ may be applied to the NGV-SIG  2150 . 
     The RNGV-SIG  2160  may be contiguous to the NGV-SIG  2150 . The RNGV-SIG  2160  may be a field in which the NGV-SIG  2150  is repeated. In other words, RNGV-SIG  2160  may include the same information fields as NGV-SIG  2150  and may be modulated in the same manner as NGV-SIG  2150  (e.g., BPSK). 
     The NGV-STF  2170  may be configured by 2x downclocking a 20 MHz VHT-STF being configured based on the IEEE 802.11ac standard. The NGV-LTF  2180  may be configured by 2x downclocking a 20 MHz VHT-LTF being configured based on the IEEE 802.11ac standard. 
     The NGV-LTF  2180  may be configured based on at least one LTF format. For example, the NGV-LTF  2180  may be configured based on one of NGV-LTF-1x format, NGV-LTF-2x format, or repeated NGV-LTF-2x format. Information related to the LTF format used for the NGV-LTF  2180  may be included in the NGV-SIG  2150 . 
     For example, the NGV-LTF-2x format may be set as a default format. As another example, the NGV-LTF-1x format may be used for high-efficiency transmission of one spatial stream (SS). As another example, the repeated NGV-LTF-2x format may be used for extended range (ER) transmissions. The repeated NGV-LTF- 2   x  format can be configured by repeating a symbol of the NGV-LTF- 2   x  format excluding a pre-append 1.6 μs duration which includes one cyclic prefix (CP) and guard interval (GI). The repeated NGV-LTF- 2   x  format may be used when dual carrier modulation (DCM) and BPSK modulation are applied to the NGV data  2190 . For example, when the DCM and BPSK modulation are applied to the NGV data  2190 , the repeated NGV-LTF- 2   x  format may be may be used/applied to the NGV-LTF  2280  regardless of information related to the LTF format included in the NGV-SIG  2150 . 
     For example, in a 10 MHz transmission, a sequence of the NGV-LTF-lx format may be configured as shown in Equation 1. 
       NGV-LTF-1 x  sequence=[ 1 ,  0 ,  1 ,  0 , − 1 ,  0 ,  1 ,  0 , − 1 ,  0 , − 1 ,  0 ,  1 ,  0 ,  1 ,  0 ,  1 ,  0 , − 1 ,  0 ,  1 ,  0 ,  1 ,  0 ,  1 ,  0 ,  1 ,  0 ,  0 ,  0 , − 1 ,  0 ,  1 ,  0 , − 1 ,  0 , − 1 ,  0 , − 1 ,  0 , − 1 ,  0 , − 1 ,  0 ,  1 ,  0 , − 1 ,  0 , − 1 ,  0 , − 1 ,  0 ,  1 ,  1 ,  1 ]  [Equation 1]
 
     For example, in a 10 MHz transmission, a sequence of the NGV-LTF-2x format may be configured as shown in Equation (2). 
       NGV-LTF-2 x  sequence=[1, 1, LTF_left, 0, LTF_right, −1, −1]  [Equation 2]
 
     In Equation 2, LTF_left and LTF_right may be configured as shown in Equation 3. 
       LTF_left=[1, 1, −1, −1, 1, −1, 1, −1, 1, 1, 1, 1, 1, −1, −1, 1, −1, 1, −1, 1, 1, 1, 1, 1]
 
       LTF_right=[1, −1, −1, 1, 1, −1, 1, −1, 1, −1, −1, −1, −1, −1, 1, 1, −1, −1, 1, −1, 1, −1, 1, 1, 1, 1]  [Equation 3]
 
     The NGV data  2190  may include a service field, PHY pad bits, and/or PSDU. 
     Although not shown, the NGV PPDU  2100  may include a midamble being continuous to the NGV data  2190 . Also, the NGV PPDU  2100  may include an additional data field being continuous to the midamble. 
     The midamble may be used to perform additional channel estimation. That is, the midamble has an effect of reducing the effect of Doppler shift. 
     The midamble may be inserted/configured in the NGV PPDU  2100  at a specified period. Information related to the designated period may be included in the NGV-SIG  2150 . For example, the NGV-SIG  2150  may include information related to a midamble periodicity. The midamble periodicity may be set to one of 4, 8, or 16. For example, when the midamble periodicity is set to 4, the NGV PPDU  2100  may include a midamble every 4 data symbols. 
     The midamble may be configured in the same format as the NGV-LTF  2180 . For example, the midamble may be set to one of the NGV-LTF- 1   x  format, the NGV-LTF- 2   x  format, or the repeated NGV-LTF- 2   x  format. Information related to the LTF format used for the midamble may be included in the NGV-SIG  2150 . 
       FIG. 22  shows another format of an NGV PPDU for a 20 MHz transmission. 
     Referring to  FIG. 22 , the NGV PPDU  2200  may be configured to have a 20 MHz bandwidth. The NGV PPDU  2200  may include an L-STF  2210 , an L-LTF  2220 , an L-SIG  2230 , an RL-SIG  2240 , an NGV-SIG  2250 , an RNGV-SIG  2260 , an NGV-STF  2270 , an NGV-LTF  2280 , and/or NGV Data  2290 . 
     The L-STF  2210 , the L-LTF  2220 , or the L-SIG  2230  may be configured by being duplicated in units of 10 MHz. The L-STF  2210 , the L-LTF  2220 , or the L-SIG  2230  may be related to the L-STF  2110 , the L-LTF  2120 , or the L-SIG  2130  of  FIG. 21 . 
     According to an embodiment, the RL-SIG  2240 , the NGV-SIG  2250 , or the RNGV-SIG  2260  may also be configured to be duplicated in units of 10 MHz. The RL-SIG  2240 , NGV-SIG  2250 , or RNGV-SIG  2260  may be related to the RL-SIG  2140 , NGV-SIG  2150 , or RNGV-SIG  2160  of  FIG. 21 . 
     The NGV-STF  2270  may be configured by 2× downclocking a 40 MHz VHT-STF being configured based on the IEEE 802.11ac standard. The NGV-LTF  2280  may be configured by 2× downclocking a 40 MHz VHT-LTF being configured based on the IEEE 802.11ac standard. 
     The NGV-LTF  2280  may be configured based on at least one format. For example, the NGV-LTF  2180  may be set to one of the NGV-LTF-1x format, the NGV-LTF-2x format, or the repeated NGV-LTF-2x format. 
     For example, in a 20 MHz transmission, a sequence of the NGV-LTF-1x format may be configured as shown in Equation 4. 
       NGV-13F-1x sequence=[1, 0, −1, 0, 1, 0, −1, 0, −1, 0, 1, 0, 1, 0, 1, 0, −1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, −1, 0, 1, 0, −1, 0, −1, 0, −1, 0, −1, 0, −1, 0, 1, 0, −1, 0, −1, 0, 1, 0, 1, 0, −1, 0, 1, 0, 0, 0, −1, 0, 1, 0, 1, 0, −1, 0, 1, 0, −1, 0, −1, 0, 1, 0, 1, 0, 1, 0, −1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, −1, 0, 1, 0, −1, 0, −1, 0,−1, 0 −1, 0, −1, 0, 1, 0, −1, 0, −1, 0, −1, 0, 1, 0, 1]  [Equation 4 ]
 
     For example, in a 20 MHz transmission, a sequence of the NGV-LTF- 2   x  format may be configured as shown in Equation 5. 
       NGV-LTF-1x sequence=[LTF_left 1, LTF_right −1, −1, −1, 1, 0, 0, 0, −1, 1, 1, −1, LTF_left, 1, LTF_right]  [Equation 5]
 
     In Equation 5, LTF_left and LTF_right may refer to Equation 3. 
     The NGV data  2290  may include a service field, PHY pad bits, and/or PSDU. The NGV data  2290  may be related to the NGV data  2190  of  FIG. 21 . 
     Although not shown, similar to the NGV PPDU  2100  of  FIG. 21 , the NGV PPDU  2200  may include a midamble being continuous to the NGV data  2290 . Also, the NGV PPDU  2200  may include an additional data field being continuous to the midamble. 
     An example of the present specification relates to an NGV PPDU (or 11bd PPDU). The NGV PPDU may be used in various wireless communication systems, for example, in an IEEE 802.11bd wireless LAN system. 
     The NGV PPDU may be referred to as various names/terminologies. For example, the NGV PPDU may be referred to as an NGV frame, an 11bd frame, an 11bd PPDU, or the like. Also, for another example, the NGV PPDU may be referred to by various names such as a first type PPDU, a transmission PPDU, a reception PPDU, and a WLAN PPDU. Hereinafter, for convenience of description, a frame of the IEEE 802.11bd standard may be referred to as the NGV PPDU. In addition, a PPDU according to the IEEE 802.11p standard may be referred to as the 11p PPDU. 
     Similarly, an STA supporting the IEEE 802.11bd standard may be referred to by various names. For example, an STA supporting the IEEE 802.11bd standard may be referred to as an 11 bd STA, an NGV STA, a transmitting STA, or a receiving STA. Hereinafter, for convenience of description, an STA supporting the IEEE 802.11bd standard may be referred to as an NGV STA. In addition, an STA supporting the IEEE 802.11p standard may be referred to as an 11p STA. In addition, the 5.9 GHz band may be variously expressed as an NGV band, a reception band, a transmission band, and the like. 
     According to the next-generation V2X communication (e.g., NGV or 802.11bd standard), a 20 MHz transmission may be supported. For example, a device according to the 802.11bd standard (hereinafter, NGV STA) may transmit an NGV PPDU configured with a bandwidth of 20 MHz. That is, the NGV PPDU may be transmitted with a bandwidth of 20 MHz. In addition, the NGV STA may transmit an NGV PPDU configured with a 10 MHz bandwidth. That is, the NGV PPDU may be transmitted with a bandwidth of 10 MHz. In other words, the NGV PPDU may be configured with a bandwidth of 10 MHz or a bandwidth of 20 MHz. 
     According to an embodiment, the NGV STA may perform channel access using a 10 MHz primary channel for a 20 MHz transmission. The NGV STA operating in the 20 MHz channel may receive a PPDU related to a service different from the service to be performed by the NGV STA through the 10 MHz primary channel When the NGV STA receives the PPDU, it may not receive an intended PPDU related to the service to be performed by the NGV STA due to unnecessary PPDU reception. Therefore, in the present specification, a method of filtering PPDUs not related to a service to be performed by an NGV STA may be proposed. 
     Specifically, an embodiment (or method) of filtering a PPDU based on bandwidth information and an embodiment (or method) of filtering a PPDU based on service information may be described below. 
     1. An embodiment of filtering PPDUs based on bandwidth information 
     The NGV STA may use bandwidth information to filter a PPDU other than a PPDU related to a service to be performed (or its own service). According to an embodiment, the NGV STA may receive an NGV PPDU or an 11p PPDU. The NGV STA may filter the PPDU in a different way when receiving the NGV PPDU and when receiving the 11p PPDU. 
     (1) When the NGV STA receives the NGV PPDU 
     According to an embodiment, the NGV STA may receive the NGV PPDU. For example, the NGV PPDU may include a first control field and a second control field. As an example, the first control field may include information related to transmission time of the NGV PPDU. The first control field may include an L-SIG (or an L-SIG field). As an example, the second control field may include information related to a bandwidth of the NGV PPDU. The second control field may include an NGV-SIG (or NGV-SIG field). 
     According to an embodiment, the NGV STA may filter the NGV PPDU based on the second control field. For example, the NGV STA may filter the NGV PPDU based on information related to the bandwidth of the NGV PPDU included in the second control field. 
     For example, the NGV STA may receive/obtain information indicating that it should perform a service through a 20 MHz bandwidth from an upper layer. In other words, the NGV STA may need to transmit and receive a PPDU of 20 MHz. The NGV STA may confirm/check that the bandwidth of a received NGV PPDU is set to 10 MHz based on the information related to the bandwidth of the NGV PPDU. Accordingly, the NGV STA may filter the received NGV PPDU. 
     As another example, the NGV STA may receive information indicating that it should perform a service through a 10 MHz bandwidth from an upper layer. In other words, the NGV STA may need to transmit and receive a PPDU of 10 MHz. The NGV STA may confirm/check that the bandwidth of a received NGV PPDU is set to 20 MHz based on the information related to the bandwidth of the NGV PPDU. Accordingly, the NGV STA may filter the received NGV PPDU. 
     According to an embodiment, the NGV STA may defer channel access based on the first control field. For example, the NGV STA may defer channel access based on information related to transmission time of the NGV PPDU included in the first control field. 
     For example, the first control field may include a length field and a rate field. That is, the NGV STA may obtain information related to the transmission time of the NGV PPDU based on the length field and the rate field. 
     Hereinafter, a detailed operation of the NGV STA related to the above-described embodiment may be described. 
     The NGV STA may be instructed to perform an operation (or service) in a 20 MHz bandwidth from an upper layer. That is, the NGV STA may be instructed to transmit/receive an NGV PPDU having a 20 MHz bandwidth from an upper layer. Thereafter, the NGV STA may receive the NGV PPDU. In other words, the NGV STA may receive information indicating that a service is to be performed through a designated bandwidth (e.g., 20 MHz) from a higher layer. Accordingly, the NGV STA may perform a service only through the designated bandwidth. That is, the NGV STA can transmit and receive only the NGV PPDU of the designated bandwidth. 
     The NGV STA operating in the 20 MHz bandwidth may compare information related to the received NGV PPDU bandwidth with the 20 MHz bandwidth indicated by the upper layer. The NGV STA may determine whether to filter the received NGV PPDU based on the comparison result. 
     For example, if the bandwidth information indicates 20 MHz, the NGV STA may decode the received NGV PPDU. In other words, the NGV STA may confirm/check that the received NGV PPDU is configured with a bandwidth of 20 MHz, based on information related to the bandwidth of the received NGV PPDU. Accordingly, the NGV STA may continue to decode the received NGV PPDU. 
     As another example, if bandwidth information indicates 10 MHz, the NGV STA may filter the received NGV PPDU. In other words, the NGV STA may confirm/check that the NGV PPDU is configured with a bandwidth of 10 MHz, based on information related to the bandwidth of the received NGV PPDU. Accordingly, the NGV STA may filter the received NGV PPDU. 
     According to an embodiment, if information related to the bandwidth of the NGV PPDU that the NGV STA is receiving through the 10 MHz primary channel is indicated as 10 MHz, the NGV STA may stop decoding the NGV PPDU being received. The NGV STA may filter the NGV PPDU being received. In this case, the NGV STA may defer channel access by the transmission time of the NGV PPDU that the NGV STA is receiving, based on information (e.g., length or rate) included in the L-SIG of the received NGV PPDU. 
     For example, when the NGV PPDU is configured with a bandwidth of 10 MHz, the NGV STA may stop decoding the NGV PPDU being received. The NGV STA may filter the NGV PPDU being received. The NGV STA may delay channel access by the transmission time of the NGV PPDU. As an example, the NGV PPDU may include an L-SIG. The L-SIG may include a length field and a rate field. The NGV STA may check the transmission time of the NGV PPDU based on a length field and a rate field. Accordingly, the NGV STA may delay channel access until the transmission of the NGV PPDU is finished. 
     According to an embodiment, at least a part of the NGV PPDU of the 20 MHz bandwidth may be configured by being duplicated in units of 10 MHz. Accordingly, the NGV STA may receive at least a portion of the NGV PPDU of the 10 MHz/20 MHz bandwidth through only the 10 MHz primary channel. The NGV STA may obtain/identify information related to the bandwidth of the NGV PPDU based on at least a part of the NGV PPDU. In other words, the NGV STA may first receive at least a part of the NGV PPDU and perform decoding. The NGV STA may obtain/identify information related to the bandwidth of the NGV PPDU by decoding at least a part of the NGV PPDU. 
     The NGV STA may again perform a PHY (or physical layer) procedure for receiving (or detecting or decoding) a new NGV PPDU. For example, the NGV STA may perform a Clear Channel Assessment-Signal Detection (CCA-SD) procedure again. The CCA-SD procedure may be a procedure for detecting the start of a PPDU occupying a 10 MHz primary channel. 
     According to the above-described embodiment, there is an effect that the NGV STA can perform decoding on only the preamble (e.g., L-SIG, NGV-SIG) and filter the received NGV PPDU. That is, the NGV STA may skip decoding the data field of the NGV PPDU not related to the service to be performed. Accordingly, there is an effect that the NGV STA can operate efficiently. 
     The NGV STA may perform the steps shown in  FIG. 25  when filtering the NGV PPDU. A detailed description of the steps shown in  FIG. 25  may be described later. 
     Bandwidth information may be indicated through the NGV PPDU. For example, information related to the bandwidth may be indicated through the NGV SIG and/or L-SIG of the NGV PPDU. In other words, bandwidth information may be included in the NGV PPDU. For example, the bandwidth information may be included in the NGV SIG and/or the L-SIG. An embodiment related thereto may be described with reference to  FIGS. 23 and/or 24 . 
     The format of the NGV PPDU shown in  FIGS. 23 and/or 24  is exemplary and the present specification is not limited thereto. For example, in the NGV PPDU shown in  FIGS. 23 and/or 24 , a repeated Non-HT SIGNAL (RL-SIG) may be further included between the L-Part and the NGV-SIG. For another example, the NGV PPDU shown in  FIGS. 23 and/or 24  may be related to the NGV PPDU  2100  shown in  FIG. 21 . 
     In  FIGS. 23 and 24 , for convenience of description, it may be assumed that the NGV STA needs to transmit and receive an NGV PPDU of a 20 MHz bandwidth. That is, the NGV STA may filter the NGV PPDU of the 10 MHz bandwidth. Examples of this can be described in  FIGS. 23 and 24 . 
       FIG. 23  is a diagram for explaining an example in which NGV PPDUs are filtered. 
     Referring to  FIG. 23 , the NGV STA  2300  may be configured to transmit/receive an NGV PPDU having a 20 MHz bandwidth. Accordingly, the NGV STA  2300  may be configured to filter the NGV PPDU of a 10 MHz bandwidth. The NGV STA  2300  may transmit and receive signals through a 10 MHz primary channel and a 10 MHz non-primary channel. 
     According to an embodiment, the NGV STA  2300  may receive the NGV PPDU  2310 . For example, the NGV STA  2300  may receive the NGV PPDU  2310  through the primary channel As an example, the NGV PPDU  2310  may be configured with a 10 MHz bandwidth. 
     According to an embodiment, the NGV STA  2300  may identify the NGV-SIG  2311  of the NGV PPDU  2310 . In other words, the NGV STA  2300  may decode the NGV-SIG  2311  of the NGV PPDU  2310 . The NGV-SIG  2311  may include information related to the bandwidth of the NGV PPDU  2310 . Accordingly, the NGV-SIG  2311  may include information indicating that the bandwidth of the NGV PPDU  2310  is 10 MHz. The NGV STA  2300  may identify that the bandwidth of the NGV PPDU  2310  is 10 MHz. 
     According to an embodiment, the NGV STA  2300  may stop decoding the NGV PPDU  2310  based on the bandwidth of the NGV PPDU  2310  being 10 MHz. Also, the NGV STA  2300  may filter the NGV PPDU  2310 . The NGV STA  2300  may defer/delay channel access until the transmission of the NGV PPDU  2310  is finished based on information included in the L-SIG, for example, a length or a rate). In other words, the NGV STA  2300  may check the transmission length of the NGV PPDU  2310 . The NGV STA  2300  may defer/delay channel access by the transmission length of the NGV PPDU  2310 . 
     Accordingly, the NGV STA  2300  may filter the NGV PPDU  2310  based on the NGV-SIG  2311 . 
       FIG. 24  is a diagram for explaining another example in which the NGV PPDU is filtered. 
     Referring to  FIG. 24 , unlike  FIG. 23 , the NGV STA  2300  may identify the L-SIG  2312  of the NGV PPDU  2310 . In other words, the NGV STA  2300  may decode the L-SIG  2312  of the NGV PPDU  2310 . The L-SIG  2312  may include information related to the bandwidth of the NGV PPDU  2310 . Accordingly, the L-SIG  2312  may include information indicating that the bandwidth of the NGV PPDU  2310  is 10 MHz. The NGV STA  2300  may identify that the bandwidth of the NGV PPDU  2310  is 10 MHz. 
     According to an embodiment, the NGV STA  2300  may stop decoding the NGV PPDU  2310  based on the bandwidth of the NGV PPDU  2310  being 10 MHz. Also, the NGV STA  2300  may filter the NGV PPDU  2310 . Also, the NGV STA  2300  may check information related to the transmission length of the NGV PPDU  2310 . The NGV STA  2300  may defer/delay channel access by the transmission length of the NGV PPDU  2310 . 
     Accordingly, the NGV STA  2300  may filter the NGV PPDU  2310  based on the L-SIG  2312 . 
       FIGS. 23 and 24  are related to an example in which information related to the bandwidth of the NGV PPDU  2310  is included in the NGV-SIG  2311  or the L-SIG  2312 . However, the present specification is not limited thereto. Accordingly,  FIGS. 23 and 24  are exemplary, and information related to the bandwidth may be included in various fields and may be indicated through various methods. 
     (2) When the NGV STA receives the 11p PPDU 
     The NGV STA may be instructed to perform an operation (or service) in a 20 MHz bandwidth from an upper layer. Since the NGV STA operates in a 20 MHz bandwidth, the NGV STA can know that the NGV PPDU is a valid PPDU, not the 11p PPDU. In other words, the NGV STA may determine that the 11p PPDU configured with the 10 MHz bandwidth is an invalid PPDU. The NGV STA may determine that an NGV PPDU configured with a 20 MHz bandwidth is a valid PPDU. 
     The NGV STA operating at 20 MHz may determine whether to filter a PPDU being received based on whether the PPDU being received through a primary channel is an NGV PPDU or an 11p PPDU. That is, when the NGV STA recognizes that the PPDU being received through the 10 MHz primary channel is an 11p PPDU, the NGV STA may filter the received PPDU. In this case, the NGV STA may defer/delay channel access until the transmission of the 11p PPDU is finished based on information included in the L-SIG, for example, a length or a rate. 
     The NGV STA may perform a PHY receive procedure (or detecting or decoding) of a new NGV PPDU again. For example, the NGV STA may perform a Clear Channel Assessment-Signal Detection (CCA-SD) procedure again. The CCA-SD procedure may be a procedure for detecting the start of a PPDU occupying a 10 MHz primary channel. 
     The NGV STA may perform the steps shown in  FIG. 25  when filtering the 11p PPDU. A detailed description of the steps shown in  FIG. 25  may be described later. 
     According to an embodiment, the 11p PPDU and the NGV PPDU may be distinguished through various methods. 
     For example, the 11p PPDU and the NGV PPDU may be distinguished based on a symbol containing a specific constellation (e.g., Q-BPSK) after the L-SIG. In other words, the NGV STA may identify the constellation of the symbol being contiguous to the L-SIG. As an example, the NGV STA may confirm/check that the received PPDU is an NGV PPDU based on the constellation of the symbol following the L-SIG being Q-BPSK. As another example, the NGV STA may confirm that the received PPDU is an NGV PPDU based on the BPSK constellation of the symbol following the L-SIG. 
     For another example, the 11p PPDU and the NGV PPDU may be distinguished based on whether the RL-SIG repeats the L-SIG after the L-SIG. In other words, the NGV STA may distinguish the 11p PPDU and the NGV PPDU based on the RL-SIG being contiguous to the L-SIG. As an example, the NGV STA may confirm that the received PPDU includes the RL-SIG. The RL-SIG may be contiguous to the L-SIG. The NGV STA may confirm that the received PPDU is an NGV PPDU based on the RL-SIG. As another example, the NGV STA may check that the received PPDU does not include the RL-SIG. The NGV STA may confirm that the received PPDU is an 11p PPDU based on that the RL-SIG is not included in the received PPDU. 
     An embodiment of classifying and filtering the 11p PPDU and the NGV PPDU in the above-described NGV STA may be described with reference to  FIGS. 25 and 26 . 
     In  FIGS. 25 and 26 , for convenience of description, it may be assumed that the NGV STA needs to transmit and receive an NGV PPDU. That is, the NGV STA may filter the 11p PPDU having a 10 MHz bandwidth. 
       FIG. 25  is a diagram for explaining an example in which an 11p PPDU is filtered. 
     Referring to  FIG. 25 , the NGV STA  2500  may be configured to transmit and receive an NGV PPDU. Accordingly, the NGV STA  2500  may be configured to filter the 11p PPDU. The NGV STA  2500  may transmit and receive signals through a 10 MHz primary channel and a 10 MHz non-primary channel. 
     According to an embodiment, the NGV STA  2500  may receive the 11p PPDU  2510 . For example, the NGV STA  2500  may receive the 11p PPDU  2510  through the primary channel. The 11p PPDU  2510  may be configured with a 10 MHz bandwidth. 
     According to an embodiment, the NGV STA  2500  may identify the constellation of the One_OFDM_Symbol  2511  of the 11p PPDU  2510 . For example, One_OFDM_Symbol  2511  may be contiguous to the L-Part. As an example, the One_OFDM_Symbol  2511  may be continuous to the L-SIG included in the L-Part. 
     Based on the One_OFDM_Symbol  2511 , the NGV STA  2500  may confirm/check whether the received PPDU is a PPDU (i.e., 11p PPDU) format configured based on the 802.11p standard or a PPDU (i.e., NGV PPDU) format configured based on the 802.11bd standard. 
     For example, the NGV STA  2500  may confirm/check that the 11p PPDU  2510  is a PPDU configured based on the 802.11p standard based on the constellation of the One_OFDM_Symbol  2511 . As an example, the NGV STA  2500  may confirm that the constellation of the One_OFDM_Symbol  2511  is not Q-BPSK. That is, the NGV STA  2500  may confirm that the 11p PPDU  2510  is not in the form of an NGV PPDU. Accordingly, the NGV STA  2500  may stop decoding the 11p PPDU  2510 . Accordingly, the NGV STA  2500  may filter the 11p PPDU  2510 . 
     The NGV STA  2500  may defer/delay channel access until the transmission of the 11p PPDU  2510  is finished based on information included in the L-SIG, for example, a length or a rate. In other words, the NGV STA  2500  may check the transmission length of the 11p PPDU  2510 . The NGV STA  2500  may defer channel access by the transmission length of the 11p PPDU  2510 . 
     Accordingly, the NGV STA  2500  may filter the 11p PPDU  2510  based on the One_OFDM_Symbol  2511 . 
       FIG. 26  is a diagram for explaining another example in which an 11p PPDU is filtered. 
     Referring to  FIG. 26 , unlike  FIG. 25 , the NGV STA  2500  may identify whether the RL-SIG of the 11p PPDU  2510  is present. For example, a PPDU format being configured based on the 802.11bd standard may include the RL-SIG. A PPDU format according to the 802.11p standard may not include the RL-SIG. Accordingly, the NGV STA  2500  may classify/distinguish a PPDU format being configured based on the 802.11p standard and a PPDU format being configured based on the 802.11bd standard based on whether the RL-SIG is present. 
     According to an embodiment, the NGV STA  2500  may check/confirm that the 11p PPDU  2510  is a PPDU format configured based on the 802.11p standard based on the 11p PPDU  2510  does not include the RL-SIG. The NGV STA  2500  may stop decoding the 11p PPDU  2510 . Also, the NGV STA  2500  may filter the 11p PPDU  2510 . Also, the NGV STA  2500  may check information related to the transmission length of the 11p PPDU  2510 . The NGV STA  2500  may defer/delay channel access by the transmission length of the 11p PPDU  2510 . 
     Accordingly, the NGV STA  2500  may filter the 11p PPDU  2510  based on the presence or absence of the RL-SIG. 
       FIGS. 25 and 26  illustrate an example of filtering the 11p PPDU  2510  based on the constellation of the One_OFDM_Symbol  2511  or the presence (or absence) of RL-SIG, but the present speciation is not limited thereto. The filtering methods of  FIGS. 25 and 26  are exemplary, and the NGV STA  2500  may distinguish the 11p PPDU and the NGV PPDU based on various methods. 
       FIG. 27  describes a flowchart of an operation of an NGV STA (e.g., NGV STAs  2300 ,  2500 ) for performing the above-described embodiments. For example, when it is decided to filter the PPDU being received by the NGV STA, the physical layer may issue PHY-RXEND.indication (Filtered) primitive. 
       FIG. 27  is a flowchart illustrating an operation of an NGV STA for filtering a PPDU. 
     Referring to  FIG. 27 , in step S 2710 , the NGV STA may configure a 20 MHz channel and a 10 MHz primary channel. According to an embodiment, the NGV STA may receive channel information from an upper layer. The information related to the channel may include information for configuring a 20 MHz channel and a 10 MHz primary channel 
     The NGV STA may receive information related to a service to be performed from a higher layer. NGV STA may confirm/check to perform a service of 20 MHz bandwidth. For example, the NGV STA may need to transmit and receive an NGV PPDU having a 20 MHz bandwidth. 
     In step S 2720 , the NGV STA may perform channel access through a 10 MHz primary channel For example, the NGV STA may perform a backoff operation on the 10 MHz primary channel based on CCA (or CCA/EDCA). 
     In step S 2730 , the NGV STA may receive a PPDU through a 10 MHz primary channel. For example, the NGV STA may receive at least a portion of the PPDU through a 10 MHz primary channel and decode at least the corresponding portion. 
     According to an embodiment, at least a portion of the 20 MHz NGV PPDU (e.g., L-STF, L-LTF, L-SIG, RL-SIG, NGV-SIG, or RNGV-SIG) is configured by being duplicated in units of 10 MHz. Therefore, even when receiving the 20 MHz NGV PPDU, the NGV STA may first receive at least a portion of the 20 MHz NGV PPDU through the 10 MHz primary channel and decode the received portion of the 20 MHz NGV PPDU. Thereafter, the NGV STA may decode the data of the 20 MHz NGV PPDU. Accordingly, the NGV STA may receive at least a portion of the PPDU through the 10 MHz primary channel and check the format of the received PPDU based on the received portion of the PPDU. 
     In step S 2740 , the NGV STA may check whether the received PPDU is a 10 MHz NGV PPDU or an 11p PPDU. 
     According to an embodiment, the NGV STA may check whether the received PPDU is an 11p PPDU. For example, the NGV STA may check whether the received PPDU is an 11p PPDU based on the OFDM symbol following the L-SIG field of the received PPDU. For example, the NGV STA may confirm/check that the received PPDU is an 11p PPDU based on that the constellation of the OFDM symbol following the L-SIG field is not Q-BPSK. As another example, the NGV STA may check whether the received PPDU is an 11p PPDU based on the presence of an RL-SIG in the received PPDU. For example, the NGV STA may confirm that the received PPDU is an 11p PPDU based on the absence of an RL-SIG in the received PPDU. In other words, the NGV STA may check whether the L-SIG is repeated after the L-SIG. The NGV STA may confirm that the received PPDU is an 11p PPDU based on that the L-SIG is not repeated after the L-SIG. 
     According to an embodiment, the NGV STA may check whether the received PPDU is an NGV PPDU of 10 MHz bandwidth. For example, the NGV STA may first check whether the received PPDU is an NGV PPDU. Thereafter, the NGV STA may check whether the received PPDU is an NGV PPDU having a 10 MHz bandwidth. 
     For example, the NGV STA may check whether the received PPDU is an NGV PPDU having a bandwidth of 10 MHz based on information related to the bandwidth included in the received PPDU. For example, the NGV-SIG of the received PPDU may include information related to the bandwidth of the PPDU. The NGV STA may confirm/check that the bandwidth of the received PPDU is 10 MHz based on the NGV-SIG. The NGV STA may confirm that the received PPDU is an NGV PPDU of 10 MHz bandwidth. As another example, the L-SIG of the received PPDU may include information related to the bandwidth of the PPDU. The NGV STA may confirm that the bandwidth of the received PPDU is 10 MHz based on the L-SIG. 
     In step S 2750 , if the received PPDU is a 10 MHz NGV PPDU or an 11p PPDU, the NGV STA may stop decoding the received PPDU and filter the received PPDU. For example, the physical layer of the NGV STA may issue PHY-RXEND.indication (Filtered) primitive. 
     In step S 2760 , when the received PPDU is not an NGV PPDU or 11p PPDU of 10 MHz bandwidth, the NGV STA may decode the received PPDU. For example, the NGV STA may continuously decode the received PPDU based on the received PPDU being an NGV PPDU having a 20 MHz bandwidth. 
     In step S 2770 , the NGV STA may defer/delay channel access and perform a procedure for receiving a new PPDU. 
     According to an embodiment, the NGV STA may defer/delay channel access by the transmission time of the received PPDU. The NGV STA may check the L-SIG of the received PPDU. The L-SIG field may include a length field and a rate field. The NGV STA may obtain information related to the transmission time of the received PPDU based on the length field and the rate field. In other words, the received PPDU may include information related to the transmission time. Thereafter, the NGV STA may delay channel access by the transmission time of the received PPDU. In other words, the NGV STA may defer/delay channel access until transmission of the received PPDU is finished. 
     According to an embodiment, the NGV STA may perform a procedure for receiving a new PPDU. For example, the NGV STA may perform a Clear Channel Assessment-Signal Detection (CCA-SD) procedure again. The CCA-SD procedure may be a procedure for detecting the start of a PPDU occupying a 10 MHz primary channel. 
     2. An embodiment of filtering PPDUs based on service-related information 
     The NGV STA may be instructed with information related to an operation bandwidth (i.e., 10 MHz or 20 MHz) from an upper layer and information related to a service capable of classifying the service. In other words, the NGV STA may receive bandwidth-related information and service-related information. The NGV STA may identify a service to be performed by the NGV STA based on the service-related information. 
     The NGV STA may receive the NGV PPDU. The NGV STA may compare the service it needs to perform with the service performed through the NGV PPDU. The NGV STA may filter the received NGV PPDU based on the comparison result. 
     For example, the NGV STA may receive first information related to a service from a higher layer. The NGV STA may receive the second information related to the service from the NGV PPDU. The NGV STA may compare the first information and the second information. The NGV STA may check whether the first service related to the first information and the second service related to the second information match. The NGV STA may filter the NGV STA when the first service and the second service do not match. The first information and the second information may be configured as follows.
         Service ID (e.g., 0, 1 or 2, etc.)   Provider Service Identifier or PSID (i.e., a service identifier indicated in IEEE 1609 standard)   Compressed PSID (i.e., technical scheme classifying PSIDs while reducing the size of PSIDs)       

     That is, information related to the service may be indicated as described above. However, the present specification is not limited thereto. Information related to the service may be indicated through various methods. 
     According to an embodiment, the NGV STA may be instructed with a Service ID from a higher layer. In other words, the NGV STA may receive information related to the Service ID from a higher layer. The NGV STA may check the value of the Service ID (hereinafter, referred to as the first Service ID) received from the higher layer. 
     In addition, the NGV STA may obtain information related to the Service ID included in the received NGV PPDU. The NGV STA may check/confirm the value of the Service ID (hereinafter, referred to as the second Service ID) obtained through the NGV PPDU. 
     For example, the value of the first Service ID may be a first value (e.g., ‘0’). Also, the value of the second Service ID may be a first value (e.g., ‘0’). The NGV STA may continue to decode the received NGV PPDU based on that the value of the first Service ID and the value of the second Service ID are the same. 
     As another example, the value of the first Service ID may be the first value (e.g., ‘0’). Also, the value of the second Service ID may be a second value (e.g., ‘1’). The NGV STA may filter the received NGV PPDU based on the difference between the value of the first Service ID and the value of the second Service ID. 
     The above-described embodiment may provide a technical effect in which the NGV STA can obtain only service-related information and filter the received NGV PPDU. That is, the NGV STA may not decode the data field of the NGV PPDU not related to the service to be performed. Accordingly, there is an effect in which the NGV STA can operate efficiently. 
     According to an embodiment, when the NGV STA filters the NGV PPDU through the above-described embodiment, the steps shown in  FIG. 29  may be performed. A detailed description of the steps shown in  FIG. 29  may be described later. 
     Information related to the above-described service may be indicated through the NGV PPDU. For example, service information may be indicated through an NGV SIG, L-SIG, or MAC header included in the NGV PPDU. 
     In other words, the above-described service-related information may be included in the NGV PPDU. For example, the service information may be included in the NGV SIG, L-SIG, or MAC header included in the NGV PPDU. 
     A detailed operation of the NGV STA according to the above-described embodiment may be described with reference to  FIG. 28 . The format of the NGV PPDU shown in  FIG. 28  is exemplary and not limited thereto. For example, in the NGV PPDU shown in  FIG. 28 , a repeated Non-HT SIGNAL (RL-SIG) may be further included between the L-Part and the NGV-SIG. For another example, the NGV PPDU shown in  FIG. 28  may be related to the NGV PPDU  2100  shown in  FIG. 21  or the NGV PPDU  2200  shown in  FIG. 22 . 
     In addition, information related to the service may be referred to as a service ID. However, the present specification is not limited thereto. The information related to the service may be set in various ways. 
       FIG. 28  is a diagram for explaining an embodiment in which a PPDU is filtered based on service-related information. 
     Referring to  FIG. 28 , the NGV STA  2800  may receive service-related information (hereinafter, first information) from a higher layer. For example, the upper layer may include a physical layer or a MAC layer. The first information may include a value of a Service ID (hereinafter, a first Service ID). For example, the value of the first Service ID may be set to a first value (e.g., ‘0’). Accordingly, the NGV STA  2800  may be configured to transmit and receive an NGV PPDU in which the value of the Service ID is set as the first value. The NGV STA may decode the data of the NGV PPDU in which the value of the Service ID is set as the first value. The NGV STA may filter the NGV PPDU in which the value of the Service ID is set as the second value. 
     The NGV STA  2300  may transmit and receive signals through a 10 MHz primary channel and a 10 MHz non-primary channel 
     According to an embodiment, the NGV STA  2800  may receive the NGV PPDU  2810 . For example, the NGV STA  2800  may receive the NGV PPDU  2810  through a primary channel. 
     According to an embodiment, the NGV STA  2800  may identify the NGV-SIG  2811  of the NGV PPDU  2810 . The NGV-SIG  2811  may include service-related information (hereinafter, second information). The second information may include a value of a Service ID (hereinafter, a second Service ID). For example, the value of the second Service ID may be set to a second value (e.g., ‘1’). Accordingly, the NGV STA  2800  may stop decoding the NGV PPDU  2810  based on the difference between the value of the first Service ID and the value of the second Service ID. The NGV STA  2800  may filter the received NGV PPDU  2810 . For example, the physical layer of the NGV STA  2800  may issue a PHY-RXEND.indication (Filtered) primitive. 
     For another example, although not shown, when the value of the second Service ID is set to the first value (e.g., ‘0’), the NGV STA  2800  may continue to decode the NGV PPDU  2810 . 
       FIG. 28  shows an example of filtering by comparing values of Service IDs, but the present specification is not limited thereto. The filtering method of  FIG. 28  is exemplary and thus not the present specification is not limited thereto. According to an embodiment, the NGV STA  2800  may perform filtering based on various information related to services. For example, the NGV STA  2800  may perform filtering based on a PSID or a compressed PSID. 
       FIG. 29 , describes a flowchart of an operation performed by an NGV STA (e.g., NGV STA  2800 ) for performing the above-described embodiments. For example, when it is decided to filter the PPDU being received by the NGV STA, the Physical layer may issue PHY-RXEND.indication (Filtered) primitive. 
       FIG. 29  is a flowchart illustrating another operation of an NGV STA for filtering a PPDU. 
     Referring to  FIG. 29 , in step S 2910 , the NGV STA (e.g., the NGV STA  2800 ) may configure a 20 MHz channel and a 10 MHz primary channel. According to an embodiment, the NGV STA may receive channel information from an upper layer. The information related to the channel (i.e., the channel information) may include information for configuring a 20 MHz channel and a 10 MHz primary channel. 
     The NGV STA may receive first information related to a service from a higher layer. The NGV STA may store first information related to the service. For example, the first information related to the service may include a first Service ID value. The NGV STA may identify a service to be performed based on the first Service ID value. For example, the first Service ID value may be set to a first value (e.g., ‘0’). 
     In step S 2920 , the NGV STA may perform channel access through a 10 MHz primary channel Step S 2920  may be related to step S 2720  of  FIG. 27 . 
     In step S 2930 , the NGV STA may receive a PPDU (e.g., an NGV PPDU) through a 10 MHz primary channel Step S 2930  may be related to step S 2730  of  FIG. 27 . 
     In step S 2940 , the NGV STA may check whether the second information related to the service of the received PPDU and the first information related to the stored service are different. 
     According to an embodiment, the NGV STA may obtain/confirm second information related to a service included in the received PPDU. The NGV STA may check the value of the second Service ID included in the second information related to the service. For example, the value of the second Service ID may be set to a second value (e.g., ‘1’). 
     The NGV STA may check whether the value of the first Service ID included in the first information related to the service is different from the value of the second Service ID included in the second information related to the service. 
     In step S 2950 , the NGV STA may stop decoding the received PPDU based on the difference between the second information related to the service and the first information related to the service. The NGV STA may filter the received PPDU. Step S 2950  may be related to step S 2750  of  FIG. 27 . 
     In step S 2960 , the NGV STA may decode the received PPDU based on that the second information related to the service is identical (or matched) to the first information related to the service. Step S 2960  may be related to step S 2760  of  FIG. 27 . 
     In step S 2970 , the NGV STA may defer/delay channel access and perform a procedure for receiving a new PPDU. Step S 2970  may be related to step S 2770  of  FIG. 27 . 
       FIG. 30  is a flowchart illustrating an operation of an STA for filtering a PPDU. 
     Referring to  FIG. 30 , in step S 3010 , an STA (e.g., NGV STAs  2300 ,  2500 ,  2800 ) may receive an NGV PPDU. 
     According to an embodiment, the NGV PPDU may include a first control field and a second control field. 
     For example, the first control field may include first information related to the transmission time of the NGV PPDU. For example, the first information related to the transmission time of the NGV PPDU may include information related to the length of the NGV PPDU and information related to the rate of the NGV PPDU. The STA may obtain the first information related to the transmission time of the NGV PPDU based on the information related to the length of the NGV PPDU and the information related to the rate of the NGV PPDU. For example, the first information related to the transmission time of the NGV PPDU may include information related to a start time at which the transmission of the NGV PPDU begins and/or an end time at which the transmission of the NGV PPDU ends. As an example, the first control field may include an L-SIG (or an L-SIG field). 
     As another example, the second control field may include second information related to the bandwidth of the NGV PPDU. As an example, the second control field may include NGV-SIG (or NGV-SIG field). 
     According to an embodiment, the STA may check service related information before receiving the NGV PPDU. For example, the STA may receive and check service-related information from an upper layer. The service-related information may include third information related to a service-related bandwidth. The STA may identify a bandwidth for performing a service based on the third information. 
     According to an embodiment, the NGV PPDU may further include a third control field in which the first control field is repeated. For example, the third control field may be continuous to the first control field. The second control field may be continuous to the third control field. The STA may filter a PPDU having a format different from that of the NGV PPDU, based on the third control field. As an example, the STA may filter a PPDU having a format different from that of the NGV PPDU, based on whether the third control field is present. As an example, the STA may filter the 11p PPDU based on the absence of the third control field. 
     According to an embodiment, the STA may transmit/receive a signal through a 10 MHz primary channel and a 10 MHz non-primary channel For example, the STA may receive the NGV PPDU (or at least a part of the NGV PPDU) through the 10 MHz primary channel. 
     In step S 3020 , the STA may filter the NGV PPDU. According to an embodiment, the STA may filter the NGV PPDU based on the second control field. 
     For example, the STA may check whether the second information is identical (or matched) to the third information. As an example, the STA may check whether the bandwidth for performing the service obtained based on the third information is identical (or matched) to the bandwidth of the NGV PPDU included in the second information. 
     For example, when the second information is not identical (or matched) to the third information, the STA may filter the NGV PPDU. For another example, when the second information is identical (or matched) to the third information, the STA may decode the NGV PPDU. For example, when the second information is identical (or matched) to the third information, the STA may decode data (or data field) of the NGV PPDU. 
     In step S 3030 , the STA may defer/delay channel access. According to an embodiment, the STA may defer/delay channel access based on the first control field. For example, the STA may check the first information regarding the transmission time of the NGV PPDU. Thereafter, the STA may defer/delay channel access by the transmission time of the NGV PPDU. In other words, the STA may defer/delay channel access until transmission of the received PPDU is finished. 
     According to an embodiment, the STA may perform a procedure for receiving a new PPDU. For example, the STA may perform a Clear Channel Assessment-Signal Detection (CCA-SD) procedure again. The CCA-SD procedure may be a procedure for detecting the start of a PPDU occupying a 10 MHz primary channel. 
     The technical features of the present specification described above may be applied to various devices and methods. For example, the above-described technical features of the present specification may be performed/supported through the apparatus of  FIGS. 1 and/or 19 . For example, the technical features of the present specification described above may be applied only to a part of  FIGS. 1 and/or 19 . For example, the technical features of the present specification described above are implemented based on the processing chips  114  and  124  of  FIG. 1 , or implemented based on the processors  111  and  121  and the memories  112  and  122  of  FIG. 1 , or, may be implemented based on the processor  610  and the memory  620  of  FIG. 19 . For example, an apparatus herein may include a memory and a processor operatively coupled to the memory, and the processor may be configured to obtain an NGV Physical Protocol Data Unit (PPDU). Further, the NGV The PPDU may include a first control field and a second control field, the first control field may include first information related to a transmission time of the NGV PPDU, and the second control field may include a second control field on a bandwidth of the NGV PPDU  2  information. The processor may be further configured to filter the NGV PPDU based on the second control field, and deferring channel access based on the first control field. 
     The technical features of the present specification may be implemented based on computer readable medium (CRM). For example, the CRM proposed by the present specification may obtain an NGV PPDU (Physical Protocol Data Unit). Further, the NGV PPDU may include a first control field and a second control field, and the first control field maybe the NGV including first information related to a transmission time of the PPDU, and the second control field may include second information related to a bandwidth of the NGV PPDU. The CRM may be further configured to filter the NGV PPDU based on the second control field; and delay channel access based on the first control field. The instructions stored in the CRM of the present specification may be executed by at least one processor. At least one processor related to CRM in the present specification may be the processors  111  and  121  or the processing chips  114  and  124  of  FIG. 1 , or the processor  610  of  FIG. 19 . Meanwhile, the CRM of the present specification may be the memories  112  and  122  of  FIG. 1 , the memory  620  of  FIG. 19 , or a separate external memory/storage medium/disk. 
     The above-described technical characteristics of the present specification may be applied to various applications or business models. For example, the UE, Terminal, STA, Transmitter, Receiver, Processor, and/or Transceiver, and so on, that are described in the present specification may be applied to vehicles that support autonomous driving or prior art vehicles that support autonomous driving. 
       FIG. 31  shows a vehicle or an autonomous driving vehicle applied to the present specification. The vehicle or autonomous driving vehicle may be implemented by a mobile robot, a car, a train, a manned/unmanned Aerial Vehicle (AV), a ship, and so on. 
     A memory unit  3130  shown in  FIG. 31  may be included in the memory(s)  112 ,  122  shown in  FIG. 1 . Additionally, a communication unit  3110  shown in  FIG. 31  may be include in the transceiver(s)  113 ,  123  and/or processor(s)  111 ,  121  shown in  FIG. 1 . Furthermore, the remaining devices that are shown in  FIG. 31  may be included in the processor(s)  111 ,  121  shown in  FIG. 1 . 
     Referring to  FIG. 31 , a vehicle or autonomous driving vehicle  3100  may include an antenna unit  3108 , a communication unit  3110 , a control unit  3120 , a memory unit  3130 , a driving unit  3140   a,  a power supply unit  3140   b,  a sensor unit  3140   c,  and/or an autonomous driving unit  3140   d.  The antenna unit  3108  may be configured as a part of the communication unit  3110 . 
     The communication unit  3110  may transmit and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, BSs (e.g., gNBs and road side units), and servers. The control unit  3120  may perform various operations by controlling elements of the vehicle or the autonomous driving vehicle  3100 . The control unit  3120  may include an Electronic Control Unit (ECU). The driving unit  3140   a  may cause the vehicle or the autonomous driving vehicle  3100  to drive on a road. The driving unit  3140   a  may include an engine, a motor, a powertrain, a wheel, a brake, a steering device, and so on. The power supply unit  3140   b  may supply power to the vehicle or the autonomous driving vehicle  3100  and include a wired/wireless charging circuit, a battery, and so on. The sensor unit  3140   c  may acquire a vehicle state, ambient environment information, user information, and so on. The sensor unit  3140   c  may include an Inertial Measurement Unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a position module, a vehicle forward/backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illumination sensor, a pedal position sensor, and so on. The autonomous driving unit  3140   d  may implement technology for maintaining a lane on which a vehicle is driving, technology for automatically adjusting speed, such as adaptive cruise control, technology for autonomously driving along a determined path, technology for driving by automatically setting a path if a destination is set, and the like. 
     For example, the communication unit  3110  may receive map data, traffic information data, and so on, from an external server. The autonomous driving unit  3140   d  may generate an autonomous driving path and a driving plan from the obtained data. The control unit  3120  may control the driving unit  3140   a  such that the vehicle or the autonomous driving vehicle  3100  may move along the autonomous driving path according to the driving plan (e.g., speed/direction control). In the middle of autonomous driving, the communication unit  3110  may aperiodically/periodically acquire recent traffic information data from the external server and acquire surrounding traffic information data from neighboring vehicles. In the middle of autonomous driving, the sensor unit  3140   c  may obtain a vehicle state and/or surrounding environment information. The autonomous driving unit  3140   d  may update the autonomous driving path and the driving plan based on the newly obtained data/information. The communication unit  3110  may transfer information related to a vehicle position, the autonomous driving path, and/or the driving plan to the external server. The external server may predict traffic information data using AI technology, and so on, based on the information collected from vehicles or autonomous driving vehicles and provide the predicted traffic information data to the vehicles or the autonomous driving vehicles. 
     An example of the present specification includes an example of  FIG. 32 , which will hereinafter be described in detail. 
       FIG. 32  shows an example of a vehicle that is applied to the present specification. The vehicle may be implemented as a transport means, an aerial vehicle, a ship, and so on. 
     Referring to  FIG. 32 , a vehicle  3100  may include a communication unit  3110 , a control unit  3120 , a memory unit  3130 , an input/output (I/O) unit  3140   e,  and a positioning unit  3140   f . Each block/unit/device shown in  FIG. 32  may be the same as each block/unit/device shown in  FIG. 31 , respectively. 
     The communication unit  3110  may transmit and receive signals (e.g., data and control signals) to and from external devices such as other vehicles or BSs. The control unit  3120  may perform various operations by controlling constituent elements of the vehicle  3100 . The memory unit  3130  may store data/parameters/programs/code/commands for supporting various functions of the vehicle  3100 . The I/O unit  3140   e  may output an AR/VR object based on information within the memory unit  3130 . The I/O unit  3140   e  may include a HUD. The positioning unit  3140   f  may acquire information related to the position of the vehicle  3100 . The position information may include information related to an absolute position of the vehicle  3100 , information related to the position of the vehicle  3100  within a traveling lane, acceleration information, and information related to the position of the vehicle  3100  from a neighboring vehicle. The positioning unit  3140   f  may include a GPS and various sensors. 
     As an example, the communication unit  3110  of the vehicle  3100  may receive map information and traffic information from an external server and store the received information in the memory unit  3130 . The positioning unit  3140   f  may obtain the vehicle position information through the GPS and various sensors and store the obtained information in the memory unit  3130 . The control unit  3120  may generate a virtual object based on the map information, traffic information, and vehicle position information and the I/O unit  3140   e  may display the generated virtual object in a window in the vehicle  3210 ,  3220 . The control unit  3120  may determine whether the vehicle  3100  normally drives within a traveling lane, based on the vehicle position information. If the vehicle  3100  abnormally exits from the traveling lane, the control unit  3120  may display a warning on the window in the vehicle through the I/O unit  3140   e.  In addition, the control unit  3120  may broadcast a warning message regarding driving abnormity to neighboring vehicles through the communication unit  3110 . According to situation, the control unit  3120  may transmit the vehicle position information and the information related to driving/vehicle abnormality to related organizations. 
     The foregoing technical features of this specification are applicable to various applications or business models. 
     For example, the foregoing technical features may be applied for wireless communication of a device supporting artificial intelligence (AI). 
     Artificial intelligence refers to a field of study on artificial intelligence or methodologies for creating artificial intelligence, and machine learning refers to a field of study on methodologies for defining and solving various issues in the area of artificial intelligence. Machine learning is also defined as an algorithm for improving the performance of an operation through steady experiences of the operation. 
     An artificial neural network (ANN) is a model used in machine learning and may refer to an overall problem-solving model that includes artificial neurons (nodes) forming a network by combining synapses. The artificial neural network may be defined by a pattern of connection between neurons of different layers, a learning process of updating a model parameter, and an activation function generating an output value. 
     The artificial neural network may include an input layer, an output layer, and optionally one or more hidden layers. Each layer includes one or more neurons, and the artificial neural network may include synapses that connect neurons. In the artificial neural network, each neuron may output a function value of an activation function of input signals input through a synapse, weights, and deviations. 
     A model parameter refers to a parameter determined through learning and includes a weight of synapse connection and a deviation of a neuron. A hyper-parameter refers to a parameter to be set before learning in a machine learning algorithm and includes a learning rate, the number of iterations, a mini-batch size, and an initialization function. 
     Learning an artificial neural network may be intended to determine a model parameter for minimizing a loss function. The loss function may be used as an index for determining an optimal model parameter in a process of learning the artificial neural network. 
     Machine learning may be classified into supervised learning, unsupervised learning, and reinforcement learning. 
     Supervised learning refers to a method of training an artificial neural network with a label given for training data, wherein the label may indicate a correct answer (or result value) that the artificial neural network needs to infer when the training data is input to the artificial neural network. Unsupervised learning may refer to a method of training an artificial neural network without a label given for training data. Reinforcement learning may refer to a training method for training an agent defined in an environment to choose an action or a sequence of actions to maximize a cumulative reward in each state. 
     Machine learning implemented with a deep neural network (DNN) including a plurality of hidden layers among artificial neural networks is referred to as deep learning, and deep learning is part of machine learning. Hereinafter, machine learning is construed as including deep learning. 
     The foregoing technical features may be applied to wireless communication of a robot. 
     Robots may refer to machinery that automatically process or operate a given task with own ability thereof. In particular, a robot having a function of recognizing an environment and autonomously making a judgment to perform an operation may be referred to as an intelligent robot. 
     Robots may be classified into industrial, medical, household, military robots and the like according uses or fields. A robot may include an actuator or a driver including a motor to perform various physical operations, such as moving a robot joint. In addition, a movable robot may include a wheel, a brake, a propeller, and the like in a driver to run on the ground or fly in the air through the driver. 
     The foregoing technical features may be applied to a device supporting extended reality. 
     Extended reality collectively refers to virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology is a computer graphic technology of providing a real-world object and background only in a CG image, AR technology is a computer graphic technology of providing a virtual CG image on a real object image, and MR technology is a computer graphic technology of providing virtual objects mixed and combined with the real world. 
     MR technology is similar to AR technology in that a real object and a virtual object are displayed together. However, a virtual object is used as a supplement to a real object in AR technology, whereas a virtual object and a real object are used as equal statuses in MR technology. 
     XR technology may be applied to a head-mount display (HMD), a head-up display (HUD), a mobile phone, a tablet PC, a laptop computer, a desktop computer, a TV, digital signage, and the like. A device to which XR technology is applied may be referred to as an XR device. 
     The claims recited in the present specification may be combined in a variety of ways. For example, the technical features of the method claims of the present specification may be combined to be implemented as a device, and the technical features of the device claims of the present specification may be combined to be implemented by a method. In addition, the technical characteristics of the method claim of the present specification and the technical characteristics of the device claim may be combined to be implemented as a device, and the technical characteristics of the method claim of the present specification and the technical characteristics of the device claim may be combined to be implemented by a method.