WO2020251196A1 - Communication technique through wireless optical communication in wireless lan system - Google Patents

Abstract

According to various embodiments, a reception STA can receive, from a transmission STA through a wireless optical communication band, a first physical layer protocol data unit (PPDU) in a first format. The first PPDU can identify information regarding a first section or information regarding a second section. The first section can comprise a section in which communication is to be performed on the basis of the first format. The second section can comprise a section in which communication is to be performed on the basis of a second format. The reception STA can transmit, to the transmission STA through the wireless optical communication band, a second PPDU in the second format on the basis of the information regarding the second section.

Description

Communication technique through wireless optical communication in wireless LAN system

The present specification relates to a technique for transmitting and receiving data in wireless communication, and more particularly, to a communication technique through wireless optical communication in a wireless LAN system.

WLAN (wireless local area network) has been improved in various ways. For example, the IEEE 802.11ax standard proposes an improved communication environment using OFDMA (orthogonal frequency division multiple access) and DL MU downlink multi-user multiple input, multiple output (MIMO) techniques.

This specification proposes technical features that can be used in a new communication standard. For example, the new communication standard may be a Light Communication (LC) standard (ie, IEEE 802.11bb standard) that is currently being discussed. The LC standard may be a standard for a wireless LAN system operating in the visible and infrared bands (ie, 380 nm to 5,000 nm wavelength) of 60 THz to 789 THz. According to the LC standard, the minimum transmission rate is 10 Mbps and the maximum transmission rate can be set to at least 5 Gbps.

Recently, as wireless traffic has exploded, demand for frequency resources is increasing. The existing electromagnetic wave band below 300 GHz is difficult to find a new band because there are many limitations such as bandwidth limitations, frequency regulation, and incumbent users. Accordingly, a wireless communication system may be required in consideration of a THz band of 300 GHz or higher, or a band in the visible and infrared regions.

A method performed by a receiving STA of a wireless local area network (LAN) system according to various embodiments includes: receiving a first type of first physical layer protocol data unit (PPDU) from a transmitting STA through a wireless optical communication band; Based on the first PPDU, information on a first section or information on a second section is identified (identify), and the receiving STA communicates with the transmitting STA based on the first format during the first section , The receiving STA communicating with the transmitting STA based on a second format during the second period; And transmitting the second PPDU of the second format to the transmitting STA through the wireless optical communication band, based on the information on the second section.

According to an embodiment of the present specification, a section for the first physical layer and/or the second physical layer may be divided. Accordingly, according to an embodiment of the present specification, collision between frames may be prevented and latency may be reduced within the entire BSS. According to an embodiment of the present specification, the transmitting STA and the receiving STA may efficiently perform communication in a wireless optical communication band.

1 shows an example of a transmitting device and/or a receiving device of the present specification.

2 is a conceptual diagram showing the structure of a wireless LAN (WLAN).

3 is a diagram illustrating a general link setup process.

4 is a diagram showing an example of a PPDU used in the IEEE standard.

5 is a diagram showing an arrangement of resource units (RU) used in a 20 MHz band.

6 is a diagram showing an arrangement of a resource unit (RU) used in a 40 MHz band.

7 is a diagram showing the arrangement of resource units (RU) used in the 80MHz band.

8 shows the structure of the HE-SIG-B field.

9 shows an example in which a plurality of User STAs are allocated to the same RU through the MU-MIMO scheme.

10 shows the operation according to the UL-MU.

11 shows an example of a trigger frame.

12 shows an example of a common information field of a trigger frame.

13 shows an example of a subfield included in a per user information field.

14 describes the technical features of the UORA technique.

15 shows an example of a channel used/supported/defined within a 2.4 GHz band.

16 shows an example of a channel used/supported/defined within a 5 GHz band.

17 shows an example of a channel used/supported/defined within a 6 GHz band.

18 shows an example of a PPDU used in the present specification.

19 shows a modified example of the transmitting device and/or the receiving device of the present specification.

20 is a diagram for describing a first physical layer.

21 shows an example of a PPDU of the first type.

22 shows an example of a second type of PPDU.

23 is a diagram for describing an example of wireless optical communication.

24 is a diagram for describing an example in which a collision occurs between STAs connected to an AP.

25 is a diagram for explaining a method for preventing collision in uplink transmission.

26 is a diagram for describing an embodiment for preventing collision between STAs through an RTS/CTS frame.

27 is a diagram for describing an example in which a collision appears between STAs.

28 is a diagram for explaining a method for preventing collision between frames.

29 is another diagram for explaining a method for preventing collision between frames.

30 is another diagram for explaining a method for preventing collision between frames.

31 is another diagram for explaining a method for preventing collision between frames.

32 is a flowchart illustrating an operation of an AP.

33 is a flowchart for describing an operation of an STA.

34 is a diagram for explaining an example of an association process.

35 is another diagram for explaining a method for preventing collision between frames.

36 is a flowchart illustrating another operation of the AP.

37 is a flowchart for explaining another operation of the STA.

38 is a flowchart illustrating an operation of a transmitting STA.

39 is a flowchart illustrating an operation of a receiving STA.

In the present specification, “A or B (A or B)” may mean “only A”, “only B” or “both A and B”. In other words, in the present specification, “A or B (A or B)” may be interpreted as “A and/or B (A and/or B)”. For example, in the present specification, “A, B or C (A, B or C)” refers to “only A”, “only B”, “only C”, or “A, B, and any combination of C ( It can mean any combination of A, B and C)”.

A forward 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 this specification, the expression “at least one of A or B” or “at least one of A and/or B” means “at least one It can be interpreted the same as "at least one of A and B".

In addition, in the present specification, “at least one of A, B and C” means “only A”, “only B”, “only C”, or “A, B and C Can mean 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" means It can mean “at least one of A, B and C”.

In addition, parentheses used in the present specification may mean "for example". Specifically, when displayed as “control information (EHT-Signal)”, “EHT-Signal” may be proposed as an example of “control information”. In other words, “control information” of the present specification is not limited to “EHT-Signal”, and “EHT-Signal” may be suggested as an example of “control information”. In addition, even when displayed as “control information (ie, EHT-signal)”, “EHT-signal” may be proposed as an example of “control information”.

In the present specification, technical features that are individually described in one drawing may be implemented individually or simultaneously.

The following example of the present specification can 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, this specification can be applied to the IEEE 802.11a/g/n/ac standard or the IEEE 802.11ax standard. In addition, this specification can be applied to the newly proposed EHT standard or IEEE 802.11be standard. In addition, an example of the present specification may be applied to the EHT standard or to a new wireless LAN standard that is improved (enhance) IEEE 802.11be. In addition, an 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 LTE (Long Term Evolution) based on 3rd Generation Partnership Project (3GPP) standard and its evolution. In addition, an example of the present specification may be applied to a communication system of 5G NR standard based on 3GPP standard.

Hereinafter, in order to describe the technical features of the present specification, technical features to which the present specification can be applied will be described.

1 shows an example of a transmitting device and/or a receiving device of the present specification.

The example of FIG. 1 may perform various technical features described below. 1 is related to at least one STA (station). For example, the STAs 110 and 120 of the present specification include a mobile terminal, a wireless device, a wireless transmit/receive unit (WTRU), a user equipment (UE), It may be referred to by various names such as a mobile station (MS), a mobile subscriber unit, or simply a user. STAs 110 and 120 of the present specification may be referred to by various names such as a network, a base station, a Node-B, an access point (AP), a repeater, a router, and a relay. The STAs 110 and 120 of the present specification may be referred to by various names such as a receiving device, a transmitting device, a receiving STA, a transmitting STA, a receiving device, and a transmitting device.

For example, the STAs 110 and 120 may perform an access point (AP) role or a non-AP role. That is, the STAs 110 and 120 of the present specification may perform AP and/or non-AP functions. In the present specification, the AP may also be indicated as an AP STA.

The STAs 110 and 120 of the present specification may support various communication standards other than the IEEE 802.11 standard together. For example, communication standards (eg, LTE, LTE-A, 5G NR standards) according to 3GPP standards may be supported. In addition, the STA of the present specification may be implemented with various devices such as a mobile phone, a vehicle, and a personal computer. In addition, the STA of the present specification may support communication for various communication services such as voice call, video call, data communication, and autonomous driving (Self-Driving, Autonomous-Driving).

In the present specification, the STAs 110 and 120 may include a medium access control (MAC) and a physical layer interface for a wireless medium according to the IEEE 802.11 standard.

The STAs 110 and 120 will be described on the basis of the sub-drawing (a) of FIG. 1 as follows.

The first STA 110 may include a processor 111, a memory 112, and a transceiver 113. The illustrated processor, memory, and transceiver may each be implemented as separate chips, or at least two or more blocks/functions may be implemented through a single chip.

The transceiver 113 of the first STA performs a signal transmission/reception operation. Specifically, IEEE 802.11 packets (eg, IEEE 802.11a/b/g/n/ac/ax/be, etc.) can be transmitted and received.

For example, the first STA 110 may perform an intended operation of the AP. For example, the processor 111 of the AP may receive a signal through the transceiver 113, process a received signal, generate a transmission signal, and perform control for signal transmission. The memory 112 of the AP may store a signal (ie, a received signal) received through the transceiver 113, and may store a signal (ie, a transmission signal) to be transmitted through the transceiver.

For example, the second STA 120 may perform an intended operation of a non-AP STA. For example, the non-AP transceiver 123 performs a signal transmission/reception operation. Specifically, IEEE 802.11 packets (eg, IEEE 802.11a/b/g/n/ac/ax/be, etc.) can be transmitted and received.

For example, the processor 121 of the non-AP STA may receive a signal through the transceiver 123, process a received signal, generate a transmission signal, and perform control for signal transmission. The memory 122 of the non-AP STA may store a signal (ie, a reception signal) received through the transceiver 123 and may store a signal (ie, a transmission signal) to be transmitted through the transceiver.

For example, in the following specification, an operation of a device indicated as an AP may be performed by the first STA 110 or the second STA 120. For example, when the first STA 110 is an AP, the operation of the device indicated as an AP is controlled by the processor 111 of the first STA 110 and is controlled by the processor 111 of the first STA 110. A related signal may be transmitted or received through the controlled transceiver 113. In addition, control information related to the operation of the AP or a transmission/reception signal of the AP may be stored in the memory 112 of the first STA 110. In addition, when the second STA 110 is an AP, the operation of the device indicated as an AP is controlled by the processor 121 of the second STA 120 and controlled by the processor 121 of the second STA 120. A related signal may be transmitted or received through the transceiver 123 being used. In addition, control information related to the operation of the AP or transmission/reception signals of the AP may be stored in the memory 122 of the second STA 110.

For example, in the following specification, an operation of a device indicated as non-AP (or User-STA) may be performed by the first STA 110 or the second STA 120. For example, when the second STA 120 is a non-AP, the operation of the device marked as non-AP is controlled by the processor 121 of the second STA 120 and the processor of the second STA 120 ( A related signal may be transmitted or received through the transceiver 123 controlled by 121). In addition, control information related to the operation of the non-AP or transmission/reception signals of the AP may be stored in the memory 122 of the second STA 120. For example, when the first STA 110 is a non-AP, the operation of the device indicated as non-AP is controlled by the processor 111 of the first STA 110 and the processor of the first STA 120 ( A related signal may be transmitted or received through the transceiver 113 controlled by 111). In addition, control information related to the operation of the non-AP or transmission/reception signals of the AP may be stored in the memory 112 of the first STA 110.

In the following specification, (transmit/receive) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmit/receive) Terminal, (transmit/receive) device , (Transmission/reception) apparatus, a device called a network, etc. may refer to the STAs 110 and 120 of FIG. 1. For example, without specific reference numerals (transmission/reception) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmission/reception) Terminal, (transmission Devices displayed as /receive) device, (transmit/receive) apparatus, network, etc. may also mean the STAs 110 and 120 of FIG. 1. For example, in the following example, an operation in which various STAs transmit and receive signals (eg, PPPDUs) may be performed by the transceivers 113 and 123 of FIG. 1. In addition, in the following example, an operation in which various STAs generate transmission/reception signals or perform data processing or calculation in advance for transmission/reception signals may be performed by the processors 111 and 121 of FIG. 1. For example, an example of an operation of generating a transmission/reception signal or performing data processing or calculation in advance for a transmission/reception signal is: 1) Determining bit information of a subfield (SIG, STF, LTF, Data) field included in the PPDU. /Acquisition/configuration/computation/decoding/encoding operations, 2) Time resources or frequency resources (eg, subcarrier resources) used for subfields (SIG, STF, LTF, Data) included in the PPDU, etc. Determination/configuration/retrieve operation, 3) A specific sequence used for the subfields (SIG, STF, LTF, Data) fields included in the PPDU (e.g., pilot sequence, STF/LTF sequence, applied to SIG) An operation of determining/configuring/obtaining an extra sequence), 4) a power control operation and/or a power saving operation applied to the STA, 5) an operation related to determination/acquisition/configuration/calculation/decoding/encoding of an ACK signal, etc. Can include. In addition, in the following example, various information used by various STAs for determination/acquisition/configuration/calculation/decoding/encoding of transmission/reception signals (for example, information related to fields/subfields/control fields/parameters/power, etc.) It may be stored in the memories 112 and 122 of FIG. 1.

The device/STA of the sub-drawing (a) of FIG. 1 described above may be modified as shown in the sub-drawing (b) of FIG. 1. Hereinafter, the STAs 110 and 120 of the present specification will be described based on the sub-drawing (b) of FIG. 1.

For example, the transceivers 113 and 123 illustrated in sub-drawing (b) of FIG. 1 may perform the same functions as the transceiver illustrated in sub-drawing (a) of FIG. 1. For example, the processing chips 114 and 124 shown in sub-drawing (b) of FIG. 1 may include processors 111 and 121 and memories 112 and 122. The processors 111 and 121 and the memories 112 and 122 illustrated in sub-drawing (b) of FIG. 1 are the processors 111 and 121 and the memories 112 and 122 illustrated in sub-drawing (a) of FIG. ) And can perform the same function.

A mobile terminal, a wireless device, a wireless transmit/receive unit (WTRU), a user equipment (UE), a mobile station (MS), and a mobile device described below. Mobile Subscriber Unit, user, user STA, network, base station, Node-B, AP (Access Point), repeater, router, relay, receiving device, transmitting device, receiving STA, transmitting The STA, the receiving device, the transmitting device, the receiving Apparatus, and/or the transmitting Apparatus means the STAs 110 and 120 shown in sub-drawings (a)/(b) of FIG. 1, or the sub-drawing of FIG. 1 (b It may mean the processing chips 114 and 124 shown in ). That is, the technical features of the present specification may be performed on the STAs 110 and 120 shown in sub-drawings (a)/(b) of FIG. 1, and the processing chip shown in sub-drawing (b) of FIG. 114, 124). For example, the technical feature of the transmitting STA transmitting the control signal is that the control signal generated by the processors 111 and 121 shown in sub-drawings (a)/(b) of FIG. 1 is sub-drawing (a) of FIG. It can be understood as a technical feature transmitted through the transceivers 113 and 123 shown in )/(b). Alternatively, the technical feature in which the transmitting STA transmits the control signal is a technical feature in which a control signal to be transmitted to the transceivers 113 and 123 is generated from the processing chips 114 and 124 shown in sub-drawing (b) of FIG. 1. Can be understood.

For example, the technical characteristic that the receiving STA receives the control signal may be understood as a technical characteristic in which the control signal is received by the transceivers 113 and 123 shown in sub-drawing (a) of FIG. 1. Alternatively, the technical feature that the receiving STA receives the control signal is that the control signal received by the transceivers 113 and 123 shown in sub-drawing (a) of FIG. 1 is the processor shown in sub-drawing (a) of FIG. 111, 121) can be understood as a technical feature obtained. Alternatively, the technical feature that the receiving STA receives the control signal is that the control signal received by the transceivers 113 and 123 shown in sub-drawing (b) of FIG. 1 is a processing chip shown in sub-drawing (b) of FIG. It can be understood as a technical feature obtained by (114, 124).

Referring to sub-drawing (b) of FIG. 1, software codes 115 and 125 may be included in the memories 112 and 122. The software codes 115 and 125 may include instructions for controlling the operations of the processors 111 and 121. The software codes 115 and 125 may be included in various programming languages.

The processors 111 and 121 or the processing chips 114 and 124 illustrated in FIG. 1 may include an application-specific integrated circuit (ASIC), another chipset, 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 the processing chips 114 and 124 shown in FIG. 1 are a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator). and demodulator). For example, the processors 111 and 121 or the processing chips 114 and 124 shown in FIG. 1 are SNAPDRAGONTM series processors manufactured by Qualcomm®, EXYNOSTM series processors manufactured by Samsung®, and It may be an A series processor, a HELIOTM series processor manufactured by MediaTek®, an ATOMTM series processor manufactured by INTEL®, or an enhanced processor thereof.

In the present specification, uplink may mean a link for communication from a non-AP STA to an AP STA, and an uplink PPDU/packet/signal may be transmitted through the uplink. In addition, in this specification, the downlink may mean a link for communication from an AP STA to a non-AP STA, and a downlink PPDU/packet/signal may be transmitted through the downlink.

2 is a conceptual diagram showing the structure of a wireless LAN (WLAN).

The upper part of FIG. 2 shows the structure of an infrastructure BSS (basic service set) of IEEE (institute of electrical and electronic engineers) 802.11.

Referring to the upper part of FIG. 2, the wireless LAN system may include one or more infrastructure BSSs 200 and 205 (hereinafter, BSS). The BSS (200, 205) is a set of APs and STAs such as an access point (AP) 225 and STA1 (Station, 200-1) that can communicate with each other by successfully synchronizing, and does not indicate a specific area. The BSS 205 may include one or more STAs 205-1 and 205-2 that can be coupled to one AP 230.

The BSS may include at least one STA, APs 225 and 230 providing a distribution service, and a distribution system (DS) 210 connecting a plurality of APs.

The distributed system 210 may implement an extended service set (ESS) 240, which is an extended service set, by connecting several BSSs 200 and 205. The ESS 240 may be used as a term indicating one network formed by connecting one or several APs through the distributed system 210. APs included in one ESS 240 may have the same service set identification (SSID).

The portal 220 may serve as a bridge for connecting a wireless LAN network (IEEE 802.11) and another network (eg, 802.X).

In the BSS as shown 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, it may be possible to perform communication by setting up a network even between STAs without the APs 225 and 230. A network that performs communication by configuring a network even between STAs without the APs 225 and 230 is defined as an ad-hoc network or an independent basic service set (IBSS).

The lower part of FIG. 2 is a conceptual diagram showing IBSS.

2, the IBSS is a BSS operating in an ad-hoc mode. Since IBSS does not include APs, there is no centralized management entity. That is, in the IBSS, the STAs 250-1, 250-2, 250-3, 255-4, and 255-5 are managed in a distributed manner. In IBSS, all STAs (250-1, 250-2, 250-3, 255-4, 255-5) can be configured as mobile STAs, and access to the distributed system is not allowed, so a self-contained network. network).

3 is a diagram illustrating a general link setup process.

In the illustrated step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access the network, it must find a network that can participate. The STA must identify a compatible network before participating in the wireless network. The process of identifying a network existing in a specific area is called scanning. Scanning methods include active scanning and passive scanning.

3 illustrates an example of a network discovery operation including an active scanning process. In active scanning, the STA performing scanning transmits a probe request frame to search for an AP present in the vicinity while moving channels and waits for a response thereto. The responder transmits a probe response frame in response to the probe request frame to the STA that has transmitted the probe request frame. Here, the responder may be an STA that last transmitted a beacon frame in the BSS of the channel being scanned. In BSS, since the AP transmits a beacon frame, the AP becomes a responder, and in IBSS, because STAs in the IBSS rotate and transmit beacon frames, the responder is not constant. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 stores BSS-related information included in the received probe response frame and stores the next channel (e.g., 2 Channel) and scanning (that is, probe request/response transmission/reception on channel 2) in the same manner.

Although not shown in the example of FIG. 3, the scanning operation may be performed in a passive scanning method. An STA performing scanning based on passive scanning may wait for a beacon frame while moving channels. The beacon frame is one of the management frames in IEEE 802.11, and is periodically transmitted so that an STA that notifies the existence of a wireless network and performs scanning can find a wireless network and participate in the wireless network. In the BSS, the AP performs a role of periodically transmitting a beacon frame, and in IBSS, the STAs in the IBSS rotate and transmit the beacon frame. When the STA performing the scanning receives the beacon frame, it stores information on the BSS included in the beacon frame, moves to another channel, and records the beacon frame information in each channel. The STA receiving the beacon frame may store BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel in the same manner.

The STA discovering the network may perform an authentication process through step SS320. This authentication process may be referred to as a first authentication process in order to clearly distinguish it from the security setup operation of step S340 to be described later. The authentication process of S320 may include a process in which the STA transmits an authentication request frame to the AP, and in response thereto, the AP transmits an authentication response frame to the STA. An authentication frame used for authentication request/response corresponds to a management frame.

The authentication frame consists of an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), and a finite cycle group. Group), etc. can be included.

The STA may transmit an authentication request frame to the AP. The AP may determine whether to allow authentication for the corresponding STA based on the information included in the received authentication request frame. The AP may provide the result of the authentication process to the STA through the authentication response frame.

The STA that has been successfully authenticated may perform a connection process based on step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and in response thereto, the AP transmits an association response frame to the STA. For example, the connection request frame includes information related to various capabilities, beacon listening intervals, service set identifiers (SSIDs), supported rates, supported channels, RSNs, and mobility domains. , Supported operating classes, TIM broadcast request, interworking service capability, and the like may be included. For example, the connection response frame includes information related to various capabilities, status codes, association IDs (AIDs), support rates, Enhanced Distributed Channel Access (EDCA) parameter sets, Received Channel Power Indicators (RCPI), Received Signal to Noise (RSNI). Indicator), mobility domain, timeout interval (association comeback time), overlapping BSS scan parameter, TIM broadcast response, QoS map, etc. may be included.

Thereafter, in step S340, the STA may perform a security setup process. The security setup process of step S340 may include, for example, a process of performing a private key setup through 4-way handshaking through an Extensible Authentication Protocol over LAN (EAPOL) frame. .

4 is a diagram showing an example of a PPDU used in the IEEE standard.

As shown, in standards such as IEEE a/g/n/ac, various types of PHY protocol data units (PPDUs) were used. Specifically, the LTF and STF fields included training signals, SIG-A and SIG-B included control information for the receiving station, and the data field included user data corresponding to PSDU (MAC PDU/Aggregated MAC PDU). Included.

In addition, FIG. 4 also includes an example of an HE PPDU of the IEEE 802.11ax standard. The HE PPDU according to FIG. 4 is an example of a PPDU for multiple users, and HE-SIG-B is included only for multiple users, and the corresponding HE-SIG-B may be omitted in the PPDU for a single user.

As shown, the HE-PPDU for multiple users (MU) is L-STF (legacy-short training field), L-LTF (legacy-long training field), L-SIG (legacy-signal), HE-SIG-A (high efficiency-signal A), HE-SIG-B (high efficiency-signal-B), HE-STF (high efficiency-short training field), HE-LTF (high efficiency-long training field) , A data field (or MAC payload), and a packet extension (PE) field. Each field may be transmitted during the illustrated time period (ie, 4 or 8 μs, etc.).

Hereinafter, a resource unit (RU) used in the PPDU will be described. The resource unit may include a plurality of subcarriers (or tones). The resource unit may be used when transmitting signals to multiple STAs based on the OFDMA technique. Also, even when a signal is transmitted to one STA, a resource unit may be defined. The resource unit can be used for STF, LTF, data fields, and the like.

5 is a diagram showing an arrangement of resource units (RU) used in a 20 MHz band.

As shown in FIG. 5, resource units (RUs) corresponding to different numbers of tones (ie, subcarriers) may be used to configure some fields of the HE-PPDU. For example, resources may be allocated in units of RU shown for HE-STF, HE-LTF, and data fields.

As shown at the top of Fig. 5, 26-units (ie, units corresponding to 26 tones) may be arranged. In the leftmost band of the 20MHz band, 6 tones may be used as a guard band, and in the rightmost band of the 20MHz band, 5 tones may be used as the guard band. In addition, 7 DC tones are inserted in the center band, that is, the DC band, and 26-units corresponding to 13 tones may exist on the left and right sides of the DC band. In addition, 26-units, 52-units, and 106-units may be allocated to other bands. Each unit can be assigned for a receiving station, i.e. a user.

Meanwhile, the RU arrangement of FIG. 5 is utilized not only in a situation for a plurality of users (MU), but also in a situation for a single user (SU). In this case, as shown in the bottom of FIG. 5, one 242-unit is used. It is possible to use and in this case 3 DC tones can be inserted.

In the example of FIG. 5, RUs of various sizes, that is, 26-RU, 52-RU, 106-RU, 242-RU, etc., have been proposed. Since the specific size of these RUs can be expanded or increased, this embodiment Is not limited to the specific size of each RU (ie, the number of corresponding tones).

6 is a diagram showing an arrangement of a resource unit (RU) used in a 40 MHz band.

Similar to the use of RUs of various sizes in the example of FIG. 5, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, and the like may be used in the example of FIG. 6. In addition, 5 DC tones can be inserted into the center frequency, 12 tones are used as guard bands in the leftmost band of the 40MHz band, and 11 tones are used in the rightmost band of the 40MHz band. It can be used as a guard band.

Also, as shown, when used for a single user, a 484-RU may be used. Meanwhile, the fact that the specific number of RUs can be changed is the same as the example of FIG. 4.

7 is a diagram showing the arrangement of resource units (RU) used in the 80MHz band.

Similar to the use of RUs of various sizes in the examples of FIGS. 5 and 6, the example of FIG. 7 may also be used with 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc. have. In addition, 7 DC tones can be inserted into the center frequency, 12 tones are used as guard bands in the leftmost band of the 80MHz band, and 11 tones are used in the rightmost band of the 80MHz band. It can be used as a guard band. In addition, 26-RU using 13 tones located on the left and right of the DC band can be used.

In addition, as shown, when used for a single user, a 996-RU may be used, and in this case, five DC tones may be inserted.

On the other hand, the fact that the specific number of RUs can be changed is the same as the examples of FIGS. 5 and 6.

The RU arrangement (ie, RU location) shown in FIGS. 5 to 7 can be applied to a new wireless LAN system (eg, EHT system) as it is. On the other hand, in the 160 MHz band supported by the new WLAN system, the RU arrangement for 80 MHz (that is, the example of FIG. 7) is repeated twice or the RU arrangement for the 40 MHz (that is, the example of FIG. 6) is 4 times. Can be repeated. In addition, when the EHT PPDU is configured in the 320 MHz band, the arrangement of the RU for 80 MHz (example of FIG. 7) may be repeated 4 times or the arrangement of the RU for 40 MHz (ie, example of FIG. 6) may be repeated 8 times. have.

One RU of the present specification may be allocated for only one STA (eg, non-AP). Alternatively, a plurality of RUs may be allocated for one STA (eg, non-AP).

The RU described herein may be used for UL (Uplink) communication and DL (Downlink) communication. For example, when UL-MU communication solicited by the trigger frame is performed, the transmitting STA (eg, AP) transmits the first RU (eg, 26/52/106) to the first STA through the trigger frame. /242-RU, etc.), and a second RU (eg, 26/52/106/242-RU, etc.) may be allocated to the 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 in the same time interval.

For example, when a DL MU PPDU is configured, the transmitting STA (eg, AP) allocates a first RU (eg, 26/52/106/242-RU, etc.) to the first STA, and 2 STAs may be assigned a second RU (eg, 26/52/106/242-RU, etc.). That is, the transmitting STA (eg, AP) may transmit the HE-STF, HE-LTF, and Data fields for the first STA through the first RU within one MU PPDU, and the second RU through the second RU. HE-STF, HE-LTF, and Data fields for 2 STAs can be transmitted.

Information on the arrangement of the RU may be signaled through HE-SIG-B.

8 shows the structure of the HE-SIG-B field.

As shown, the 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 (ie, user STAs) receiving the SIG-B. The user-individual field 830 may be referred to as a user-individual control field. When the SIG-B is transmitted to a plurality of users, the user-individual field 830 may be applied to only some of the plurality of users.

As shown in FIG. 8, the common field 920 and the user-individual field 930 may be encoded separately.

The common field 920 may include RU allocation information of N*8 bits. For example, the RU allocation information may include information on the location of the RU. For example, when a 20 MHz channel is used as shown in FIG. 5, the RU allocation information may include information on which RU (26-RU/52-RU/106-RU) is allocated in which frequency band. .

An example of a case in which RU allocation information is composed of 8 bits is as follows.

As in the example of FIG. 5, a maximum of 9 26-RUs may be allocated to a 20 MHz channel. As shown in Table 1, when the RU allocation information of the common field 820 is set to “00000000”, nine 26-RUs may be allocated to a corresponding channel (ie, 20 MHz). In addition, as shown in Table 1, when the RU allocation information of the common field 820 is set to "00000001", seven 26-RUs and one 52-RU are arranged in a corresponding channel. That is, in the example of FIG. 5, 52-RUs may be allocated to the rightmost side and seven 26-RUs may be allocated to the left side.

An example of Table 1 shows only some of the RU locations that can be displayed by RU allocation information.

For example, RU allocation information may include an example of Table 2 below.

"01000y2y1y0" relates to an example in which 106-RU is allocated to the leftmost-left side of a 20 MHz channel, and five 26-RUs are allocated to the right side. In this case, a plurality of STAs (eg, User-STAs) may be allocated to the 106-RU based on the MU-MIMO technique. Specifically, up to 8 STAs (eg, User-STA) may be allocated to 106-RU, and the number of STAs (eg, User-STA) allocated to 106-RU is 3-bit information (y2y1y0). ). For example, when 3-bit information (y2y1y0) is set to N, the number of STAs (eg, User-STAs) allocated to 106-RU based on the MU-MIMO technique may be N+1.

In general, a plurality of different STAs (eg, user STAs) may be allocated to a plurality of RUs. However, for one RU of a specific size (eg, 106 subcarriers) or more, a plurality of STAs (eg, user STAs) may be allocated based on the MU-MIMO technique.

As shown in FIG. 8, the user-individual field 830 may include a plurality of user fields. As described above, the number of STAs (eg, user STAs) allocated to a specific channel may be determined based on the RU allocation information in 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 (ie, a total of 9 User STAs are allocated). That is, up to 9 User STAs may be allocated to a specific channel through the 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 User STAs are allocated to 106-RUs disposed on the leftmost-left through the MU-MIMO scheme, and five 26-RUs disposed on the right side are allocated Five User STAs may be allocated through a non-MU-MIMO scheme. This case is embodied through an example of FIG. 9.

9 shows an example in which a plurality of User STAs are allocated to the same RU through the MU-MIMO scheme.

For example, when RU allocation is set to “01000010” as shown in FIG. 9, based on Table 2, 106-RUs are allocated to the leftmost-left side of a specific channel, and five 26-RUs are allocated to the right side. I can. In addition, a total of three User STAs may be allocated to the 106-RU through the MU-MIMO scheme. As a result, since a total of 8 User STAs are allocated, the user-individual field 830 of HE-SIG-B may include 8 User fields.

Eight User fields may be included in the order shown in FIG. 9. In addition, as shown in FIG. 8, two User fields may be implemented as one User block field.

The User field shown in FIGS. 8 and 9 may be configured based on two formats. That is, a User field related to the MU-MIMO technique may be configured in a first format, and a User field related to the non-MU-MIMO technique may be configured in a second format. Referring to the example of FIG. 9, User fields 1 to 3 may be based on a first format, and User fields 4 to 8 may be based on a second format. The first format or the second format may include bit information of the same length (eg, 21 bits).

Each User field may have the same size (eg, 21 bits). For example, the User Field of the first format (the format of the MU-MIMO scheme) may be configured as follows.

For example, the first bit (eg, B0-B10) in the user field (ie, 21 bits) is the identification information of the user STA to which the corresponding user field is allocated (eg, STA-ID, partial AID, etc.) It may include. In addition, the second bit (eg, B11-B14) in the user field (ie, 21 bits) may include information on spatial configuration. Specifically, an example of the second bit (ie, B11-B14) may be as shown in Tables 3 to 4 below.

As shown in Table 3 and/or Table 4, the second bit (i.e., B11-B14) may include information on the number of Spatial Streams allocated to a plurality of User STAs allocated according to the MU-MIMO scheme. have. For example, when three User STAs are allocated to 106-RU based on the MU-MIMO scheme as shown in FIG. 9, N_user is set to “3”, and accordingly, as shown in Table 3, N_STS[1], Values of N_STS[2] and N_STS[3] may be determined. For example, when the value of the second bits B11-B14 is “0011”, it may be set to N_STS[1]=4, N_STS[2]=1, and N_STS[3]=1. That is, in the example of FIG. 9, 4 Spatial Streams may be allocated to User field 1, 1 Spatial Stream may be allocated to User field 2, and 1 Spatial Stream may be allocated to User field 3.

As in the example of Table 3 and/or Table 4, information on the number of spatial streams for a user STA (that is, the second bit, B11-B14) may consist of 4 bits. In addition, information on the number of spatial streams for a user STA (ie, second bits, B11-B14) may support up to eight spatial streams. In addition, information on the number of spatial streams (ie, second bits, B11-B14) may support up to 4 spatial streams for one user STA.

In addition, the third bit (ie, B15-18) in the user field (ie, 21 bits) may include MCS (Modulation and coding scheme) information. MCS information may be applied to a data field in a PPDU in which the corresponding SIG-B is included.

MCS, MCS information, MCS index, MCS field, and the like used in the present specification may be indicated by a specific index value. For example, MCS information may be indicated by index 0 to index 11. The MCS information includes information on a constellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, etc.), and a coding rate (e.g., 1/2, 2/ 3, 3/4, 5/6, etc.). Information on the channel coding type (eg, BCC or LDPC) may be excluded from the MCS information.

In addition, the fourth bit (ie, B19) in the user field (ie, 21 bits) may be a reserved field.

In addition, the fifth bit (ie, B20) in the user field (ie, 21 bits) may include information on the coding type (eg, BCC or LDPC). That is, the fifth bit (ie, B20) may include information on the type of channel coding (eg, BCC or LDPC) applied to the data field in the PPDU including the corresponding SIG-B.

The above-described 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 (non-MU-MIMO format) is as follows.

The first bit (eg, B0-B10) in the User field of the second format may include identification information of the User STA. In addition, the second bit (eg, B11-B13) in the user field of the second format may include information on the number of spatial streams applied to the corresponding RU. In addition, the third bit (eg, B14) in the user field of the second format may include information on whether the beamforming steering matrix is applied. The fourth bit (eg, B15-B18) in the User field of the second format may include MCS (Modulation and Coding Scheme) information. In addition, the fifth bit (eg, B19) in the User field of the second format may include information on whether or not Dual Carrier Modulation (DCM) is applied. In addition, the sixth bit (ie, B20) in the user field of the second format may include information on the coding type (eg, BCC or LDPC).

10 shows the operation according to the UL-MU. As shown, a transmitting STA (eg, an AP) may perform channel access through contending (ie, a backoff operation) and transmit a trigger frame 1030. That is, the transmitting STA (eg, AP) may transmit a PPDU including the trigger frame 1330. When a PPDU including a trigger frame is received, a trigger-based (TB) PPDU is transmitted after a delay equal to SIFS.

The TB PPDUs 1041 and 1042 may be transmitted at the same time slot and may be transmitted from a plurality of STAs (eg, User STAs) in which an AID is indicated in the trigger frame 1030. The ACK frame 1050 for the TB PPDU may be implemented in various forms.

Specific characteristics of the trigger frame will be described with reference to FIGS. 11 to 13. Even when UL-MU communication is used, an orthogonal frequency division multiple access (OFDMA) technique or an MU MIMO technique can be used, and an OFDMA and MU MIMO technique can be used simultaneously.

11 shows an example of a trigger frame. The trigger frame of FIG. 11 allocates resources for uplink multiple-user transmission (MU), and may be transmitted from an AP, for example. The trigger frame may be composed of a MAC frame and may be included in a PPDU.

Each of the fields shown in FIG. 11 may be partially omitted, and other fields may be added. Also, the length of each field may be changed differently from that shown.

The frame control field 1110 of FIG. 11 includes information on the version of the MAC protocol and other additional control information, and the duration field 1120 is time information for setting NAV or an identifier of the STA (for example, For example, information on AID) may be included.

In addition, the RA field 1130 includes address information of the receiving STA of the corresponding trigger frame, and may be omitted if necessary. The TA field 1140 includes address information of an STA (eg, an AP) that transmits a corresponding trigger frame, and a common information field 1150 is a common information applied to a receiving STA receiving a corresponding trigger frame. Contains control information. For example, a field indicating the length of an L-SIG field of an uplink PPDU transmitted in response to a corresponding trigger frame, or a SIG-A field of an uplink PPDU transmitted in response to a corresponding trigger frame (i.e., HE-SIG-A Field) may contain information that controls the content. In addition, as common control information, information about a length of a CP of an uplink PPDU transmitted in response to a corresponding trigger frame or information about a length of an LTF field may be included.

In addition, it is preferable to include individual user information fields 1160#1 to 1160#N corresponding to the number of receiving STAs receiving the trigger frame of FIG. 11. The individual user information field may be referred to as 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 individual user information fields 1160#1 to 1160#N shown in FIG. 11 may again include a plurality of subfields.

12 shows an example of a common information field of a trigger frame. Some of the subfields of FIG. 12 may be omitted, and other subfields may be added. In addition, the length of each of the illustrated subfields may be changed.

The illustrated length field 1210 has the same value as the length field of the L-SIG field of the uplink PPDU transmitted in response to the corresponding trigger frame, and the length field of the L-SIG field of the uplink PPDU represents the 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.

Also, the cascade indicator field 1220 indicates whether a cascade operation is performed. The cascade operation means that downlink MU transmission and uplink MU transmission are performed together within the same TXOP (Transmit Opportunity). That is, after downlink MU transmission is performed, it means that uplink MU transmission is performed after a preset time (eg, SIFS). During a casecade operation, there may be only one transmission device (eg, AP) performing downlink communication, and a plurality of transmission devices (eg, non-AP) performing uplink communication may exist.

The CS request field 1230 indicates whether to consider the state of the radio medium or the NAV in a situation in which the receiving device receiving the corresponding trigger frame transmits the corresponding uplink PPDU.

The HE-SIG-A information field 1240 may include information for controlling the content of the SIG-A field (ie, the HE-SIG-A field) of the uplink PPDU transmitted in response to the corresponding trigger frame.

The CP and LTF type field 1250 may include information on the length of the LTF and the CP length of the uplink PPDU transmitted in response to the corresponding trigger frame. The trigger type field 1060 may indicate a purpose for which the corresponding trigger frame is used, for example, normal triggering, triggering for beamforming, and request for Block ACK/NACK.

In this specification, it may be assumed that the trigger type field 1260 of the trigger frame indicates a basic type of trigger frame for normal triggering. For example, a basic type trigger frame may be referred to as a basic trigger frame.

13 shows an example of a subfield included in a per user information field. The user information field 1300 of FIG. 13 may be understood as any of the individual user information fields 1160#1 to 1160#N mentioned in FIG. 11 above. Some of the subfields included in the user information field 1300 of FIG. 13 may be omitted, and other subfields may be added. In addition, the length of each of the illustrated subfields may be changed.

A user identifier field 1310 of FIG. 13 indicates an identifier of an STA (ie, a receiving STA) corresponding to per user information, and an example of the identifier is an association identifier (AID) of the receiving STA. It can be all or part of the value.

In addition, an RU Allocation field 1320 may be included. That is, when the receiving STA identified by the user identifier field 1310 transmits the TB PPDU corresponding to the trigger frame, it transmits the TB PPDU through the RU indicated by the RU allocation field 1320. In this case, the RU indicated by the RU Allocation field 1320 may be the RU shown in FIGS. 5, 6, and 7.

The subfield of FIG. 13 may include a coding type field 1330. The coding type field 1330 may indicate the 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'. have.

In addition, the subfield of FIG. 13 may include an MCS field 1340. The MCS field 1340 may indicate an MCS scheme applied to a 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'. have.

Hereinafter, a UL OFDMA-based Random Access (UORA) technique will be described.

14 describes the technical features of the UORA technique.

The transmitting STA (eg, AP) may allocate 6 RU resources as shown in FIG. 14 through a trigger frame. Specifically, the AP is a first RU resource (AID 0, RU 1), a second RU resource (AID 0, RU 2), a third RU resource (AID 0, RU 3), a fourth RU resource (AID 2045, RU 4), a fifth RU resource (AID 2045, RU 5), and a sixth RU resource (AID 3, RU 6) may be allocated. Information on AID 0, AID 3, or AID 2045 may be included, for example, in the user identification field 1310 of FIG. 13. Information about RU 1 to RU 6 may be included in, for example, the RU allocation field 1320 of FIG. 13. AID=0 may mean a UORA resource for an associated STA, and AID=2045 may mean a UORA resource for an un-associated STA. Accordingly, the first to third RU resources of FIG. 14 may be used as UORA resources for an associated STA, and the fourth to fifth RU resources of FIG. 14 are for un-associated STAs. It may be used as a UORA resource, and the sixth RU resource of FIG. 14 may be used as a resource for a normal UL MU.

In the example of FIG. 14, the OBO (OFDMA random access BackOff) counter of STA1 is reduced to 0, and STA1 randomly selects the second RU resources (AID 0, RU 2). In addition, since the OBO counter of STA2/3 is greater than 0, uplink resources are not allocated to STA2/3. In addition, since STA4 in FIG. 14 includes its AID (ie, AID=3) in the trigger frame, resources of RU 6 are allocated without backoff.

Specifically, since STA1 of FIG. 14 is an associated STA, there are a total of three eligible RA RUs for STA1 (RU 1, RU 2, RU 3), and accordingly, STA1 decreases the OBO counter by 3 so that the OBO counter is It became 0. In addition, since STA2 of FIG. 14 is an associated STA, there are a total of three eligible RA RUs for STA2 (RU 1, RU 2, and RU 3). Accordingly, STA2 has reduced the OBO counter by 3, but the OBO counter is 0. Is in a larger state. In addition, since STA3 of FIG. 14 is an un-associated STA, there are a total of two eligible RA RUs (RU 4 and RU 5) for STA3, and accordingly, STA3 has reduced the OBO counter by 2, but the OBO counter is It is in a state greater than 0.

15 shows an example of a channel used/supported/defined within a 2.4 GHz band.

The 2.4 GHz band may be referred to by other names such as the first band (band). In addition, the 2.4 GHz band may refer to a frequency region in which channels having a center frequency adjacent to 2.4 GHz (eg, channels having a center frequency located within 2.4 to 2.5 GHz) are used/supported/defined.

The 2.4 GHz band may contain multiple 20 MHz channels. 20 MHz in the 2.4 GHz band may have multiple channel indexes (eg, index 1 to index 14). For example, a center frequency of a 20 MHz channel to which channel index 1 is assigned may be 2.412 GHz, a center frequency of a 20 MHz channel to which channel index 2 is assigned may be 2.417 GHz, and 20 MHz to which channel index N is assigned The center frequency of the channel may be (2.407 + 0.005*N) GHz. The channel index may be referred to by various names such as channel number. Specific values of the channel index and the center frequency may be changed.

15 exemplarily shows four channels in a 2.4 GHz band. Each of the illustrated first to fourth frequency regions 1510 to 1540 may include one channel. For example, the first frequency domain 1510 may include channel 1 (a 20 MHz channel having index 1). At this time, the center frequency of channel 1 may be set to 2412 MHz. The second frequency domain 1520 may include channel 6. At this time, the center frequency of channel 6 may be set to 2437 MHz. The third frequency domain 1530 may include channel 11. At this time, the center frequency of channel 11 may be set to 2462 MHz. The fourth frequency domain 1540 may include channel 14. At this time, the center frequency of channel 14 may be set to 2484 MHz.

16 shows an example of a channel used/supported/defined within a 5 GHz band.

The 5 GHz band may be referred to by another name such as the second band/band. The 5 GHz band may mean a frequency range in which channels having a center frequency of 5 GHz or more 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. The specific values shown in FIG. 16 may be changed.

The plurality of channels in the 5 GHz band include UNII (Unlicensed National Information Infrastructure)-1, UNII-2, UNII-3, and ISM. UNII-1 can be called UNII Low. UNII-2 may include a frequency domain called UNII Mid and UNII-2 Extended. UNII-3 can be called UNII-Upper.

A plurality of channels may be set within the 5 GHz band, and the bandwidth of each channel may be variously set to 20 MHz, 40 MHz, 80 MHz, or 160 MHz. For example, a frequency range/range of 5170 MHz to 5330 MHz in UNII-1 and UNII-2 may be divided into eight 20 MHz channels. The frequency range/range from 5170 MHz to 5330 MHz can be divided into four channels through the 40 MHz frequency domain. The 5170 MHz to 5330 MHz frequency domain/range can be divided into two channels through the 80 MHz frequency domain. Alternatively, the 5170 MHz to 5330 MHz frequency domain/range may be divided into one channel through the 160 MHz frequency domain.

17 shows an example of a channel used/supported/defined within a 6 GHz band.

The 6 GHz band may be referred to as a third band/band. The 6 GHz band may mean a frequency range in which channels with a center frequency of 5.9 GHz or more are used/supported/defined. The specific values shown in FIG. 17 may be changed.

For example, the 20 MHz channel of FIG. 17 may be defined from 5.940 GHz. Specifically, the leftmost channel of the 20 MHz channel of FIG. 17 may have an index number 1 (or a channel index, a channel number, etc.), and a center frequency of 5.945 GHz may be allocated. That is, the center frequency of the index N channel may be determined as (5.940 + 0.005*N) GHz.

Accordingly, the index (or channel number) of the 20 MHz channel of FIG. 17 is 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, It may be 165, 169, 173, 177, 181, 185, 189, 193, 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. In addition, according to the above-described (5.940 + 0.005*N) GHz rule, the index of the 40 MHz channel in FIG. 17 is 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.

In the example of FIG. 17, 20, 40, 80, and 160 MHz channels are shown, but additionally, a 240 MHz channel or a 320 MHz channel may be added.

Hereinafter, the PPDU transmitted/received by the STA of the present specification will be described.

18 shows an example of a PPDU used in the present specification.

The PPDU of FIG. 18 may be referred to as various names such as EHT PPDU, transmission PPDU, reception PPDU, 1st type or Nth type PPDU. In addition, it can be used in the EHT system and/or a new wireless LAN system that has improved the EHT system.

The subfields of FIG. 18 may be changed to various names. For example, the SIG A field may be referred to as an EHT-SIG-A field, an SIG B field may be referred to as an EHT-SIG-B, an STF field may be referred to as an EHT-STF field, and an LTF field may be referred to as an EHT-LTF field.

The subcarrier spacing of the L-LTF, L-STF, L-SIG, and RL-SIG fields of FIG. 18 may be set to 312.5 kHz, and the subcarrier spacing of the STF, LTF, and Data fields may be set to 78.125 kHz. That is, the subcarrier index of the L-LTF, L-STF, L-SIG, and RL-SIG fields may be displayed in units of 312.5 kHz, and the subcarrier indexes of the STF, LTF, and Data fields may be displayed in units of 78.125 kHz.

The SIG A and/or SIG B fields of FIG. 18 may include additional fields (eg, SIG C or one control symbol, etc.). Of the SIG A and SIG B fields, all/some of the subcarrier spacing and all/some of the additionally defined SIG fields may be set to 312.5 kHz. Meanwhile, the subcarrier spacing for a part of the newly defined SIG field may be set to a preset value (eg, 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 the conventional field.

The L-SIG field of FIG. 18 may include, for example, 24-bit bit information. For example, the 24-bit information may include a 4 bit Rate field, 1 bit Reserved bit, 12 bit Length field, 1 bit Parity bit, and 6 bit Tail bit. For example, the 12-bit Length field may include information on the number of octets of a Physical Service Data Unit (PSDU). For example, the value of the 12-bit Length field may be determined based on the type of PPDU. For example, when the PPDU is a non-HT, HT, VHT PPDU or EHT PPDU, the 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 “multiple of 3 + 1” or “multiple of 3 +2”. In other words, for non-HT, HT, VHT PPDU or EHT PPDU, the value of the Length field can be determined as a multiple of 3, and for HE PPDU, the value of the Length field is "multiple of 3 + 1" or "multiple of 3 It can be determined as +2”.

For example, the transmitting STA may apply BCC encoding based on a code rate of 1/2 to 24-bit information of the L-SIG field. Thereafter, the transmitting STA may obtain a 48-bit BCC coded bit. BPSK modulation is applied to the 48-bit coded bits, so that 48 BPSK symbols may be generated. The transmitting STA may map 48 BPSK symbols to locations excluding pilot subcarriers {subcarrier index -21, -7, +7, +21} and DC subcarrier {subcarrier index 0}. As a result, 48 BPSK symbols can be mapped to subcarrier indices -26 to -22, -20 to -8, -6 to -1, +1 to +6, +8 to +20, and +22 to +26. have. The transmitting STA may additionally map a signal of {-1, -1, -1, 1} to the subcarrier index {-28, -27, +27, +28}. The above signal can be used for channel estimation in the frequency domain corresponding to {-28, -27, +27, +28}.

The transmitting STA may generate the RL-SIG generated in the same manner as the L-SIG. BPSK modulation can be applied to RL-SIG. The receiving STA may know that the received PPDU is an HE PPDU or an 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. Symbols located after RL-SIG (ie, EHT-SIG-A or one control symbol in the present specification) may be referred to as various names such as a U-SIG (Universal SIG) field.

A symbol (eg, U-SIG) consecutive to the RL-SIG may include information of N bits, and may include information for identifying the type of EHT PPDU. For example, the U-SIG may be configured based on two symbols (eg, two consecutive OFDM symbols). Each symbol (eg, OFDM symbol) for U-SIG may have a duration of 4 us. Each symbol of U-SIG can be used to transmit 26 bits of information. For example, each symbol of U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

Through the U-SIG (or U-SIG field), for example, A-bit information (eg, 52 un-coded bits) may be transmitted, and the first symbol of U-SIG is the first of the total A-bit information. X-bit information (eg, 26 un-coded bits) is transmitted, and the second symbol of U-SIG can transmit remaining Y-bit information (eg, 26 un-coded bits) of the total A-bit information. have. For example, the transmitting STA may acquire 26 un-coded bits included in each U-SIG symbol. The transmitting STA may generate a 52-coded bit by performing convolutional encoding on the basis of a rate of R=1/2, and may perform interleaving on the 52-coded bit. The transmitting STA may generate 52 BPSK symbols allocated to each U-SIG symbol by performing BPSK modulation on the interleaved 52-coded bits. One U-SIG symbol may be transmitted based on 56 tones (subcarriers) from subcarrier index -28 to subcarrier index +28, excluding DC index 0. 52 BPSK symbols generated by the transmitting STA may be transmitted based on the remaining tones (subcarriers) excluding the pilot tones -21, -7, +7, and +21 tones.

For example, A-bit information (e.g., 52 un-coded bits) transmitted by U-SIG is a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). ) Can be included. The CRC field and the tail field may be transmitted through the second symbol of U-SIG. The CRC field may be generated based on 26 bits allocated to the first symbol of U-SIG and the remaining 16 bits excluding the CRC/tail field in the second symbol, and may be generated based on a conventional CRC calculation algorithm. I can. In addition, the tail field may be used to terminate trellis of a convolutional decoder, and may be set to “000000”, for example.

A bit information (eg, 52 un-coded bits) transmitted by U-SIG (or U-SIG field) may be divided into version-independent bits and version-dependent bits. For example, the size of version-independent bits may be fixed or variable. For example, version-independent bits may be allocated only to the first symbol of U-SIG, or version-independent bits may be allocated to both the first symbol and the second symbol of U-SIG. For example, version-independent bits and version-dependent bits may be referred to by various names such as a first bit and a second bit.

For example, the version-independent bits of U-SIG may include a 3-bit PHY version identifier. For example, the 3-bit PHY version identifier may include information related to the PHY version of the transmission/reception PPDU. For example, the first value of the 3-bit PHY version identifier may indicate that the transmission/reception PPDU is an EHT PPDU. In other words, when transmitting the EHT PPDU, the transmitting STA may set a 3-bit PHY version identifier as the first value. In other words, the receiving STA may determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value.

For example, the version-independent bits of U-SIG may include a 1-bit UL/DL flag field. The first value of the 1-bit UL/DL flag field is related to UL communication, and the second value of the UL/DL flag field is related to DL communication.

For example, the version-independent bits of U-SIG may include information on the length of TXOP and information on the BSS color ID.

For example, when the EHT PPDU is classified into various types (e.g., EHT PPDU supporting SU, EHT PPDU supporting MU, EHT PPDU related to Trigger Frame, EHT PPDU related to Extended Range transmission, etc.) , Information about the type of the EHT PPDU may be included in version-independent bits or version-dependent bits of U-SIG.

For example, the U-SIG field is 1) a bandwidth field containing information about the bandwidth, 2) a field containing information about the MCS technique applied to SIG-B, and 3) dual subcarrier modulation in SIG-B ( An indication field containing information related to whether or not dual subcarrier modulation) is applied, 4) A field containing information about the number of symbols used for SIG-B, 5) Whether SIG-B is generated over the entire band It may include a field including information on whether or not, 6) a field including information on an LTF/STF type, and 7) information on a field indicating the length of the LTF and the length of the CP.

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.

The 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. The LTF of FIG. 18 may be used to estimate a channel in a MIMO environment or an OFDMA environment.

The STF of FIG. 18 may be set in various types. For example, the first type of STF (that is, 1x STF) may be generated based on a first type STF sequence in which non-zero coefficients are arranged at 16 subcarrier intervals. The STF signal generated based on the first type STF sequence may have a period of 0.8 μs, and the 0.8 μs period signal may be repeated 5 times to become a first type STF having a length of 4 μs. For example, the second type of STF (that is, 2x STF) may be generated based on a second type STF sequence in which non-zero coefficients are arranged at 8 subcarrier intervals. The STF signal generated based on the second type STF sequence may have a period of 1.6 μs, and the 1.6 μs period signal may be repeated 5 times to become a second type EHT-STF having a length of 8 μs. For example, a third type of STF (ie, 4x EHT-STF) may be generated based on a third type STF sequence in which non-zero coefficients are arranged at intervals of four subcarriers. The STF signal generated based on the third type STF sequence may have a period of 3.2 μs, and the period signal of 3.2 μs may be repeated 5 times to become a third type EHT-STF having a length of 16 μs. Only some of the above-described first to third type EHT-STF sequences may be used. In addition, the EHT-LTF field may have first, second, and third types (ie, 1x, 2x, 4x LTF). For example, the first/second/third type LTF field may be generated based on an LTF sequence in which non-zero coefficients are arranged at 4/2/1 subcarrier intervals. The first/second/third type LTF may have a time length of 3.2/6.4/12.8 μs. In addition, GIs of various lengths (eg, 0.8/1/6/3.2 μs) may be applied to the first/second/third type LTF.

Information on the type of STF and/or LTF (including information on 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, some fields (eg, STF, LTF, data) of FIG. 18 may be configured based on RUs shown 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 (ie, when MU PPDU is used), some fields (eg, STF, LTF, data) of FIG. 18 are shown in FIGS. 5 to 7, etc. It can be configured based on the RU. For example, the STF, LTF, and data fields for the first receiving STA of the PPDU may be transmitted and received through the first RU, and the STF, LTF, and data fields for the second receiving STA of the PPDU are transmitted and received through the second RU. Can be. In this case, the 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.

The receiving STA may determine the type of the received PPDU as the EHT PPDU based on the following items. For example, 1) the first symbol after the L-LTF signal of the received PPDU is BPSK, 2) RL-SIG where the L-SIG of the received PPDU is repeated is detected, and 3) the length of the L-SIG of the received PPDU When the result of applying “modulo 3” to the value is detected as “0”, the received PPDU may be determined as an EHT PPDU. When the received PPDU is determined to be an EHT PPDU, the receiving STA is the type of the EHT PPDU (e.g., SU/MU/Trigger-based/Extended Range type) based on bit information included in the symbol after RL-SIG of FIG. ) Can be detected. In other words, the receiving STA is 1) the first symbol after the L-LTF signal, which is BSPK, 2) RL-SIG that is consecutive to the L-SIG field and is the same as L-SIG, 3) the result of applying “modulo 3” is “ L-SIG including a Length field set to 0”, and 4) a received PPDU based on a 3-bit PHY version identifier (eg, a PHY version identifier having a first value) of the aforementioned U-SIG. It can be judged as an EHT PPDU.

For example, the receiving STA may determine the type of the received PPDU as an HE PPDU based on the following. For example, 1) the first symbol after the L-LTF signal is BPSK, 2) RL-SIG repeating L-SIG is detected, and 3) “modulo 3” is applied to the length value of L-SIG. When the result is detected as “1” or “2”, the received PPDU may be determined as an HE PPDU.

For example, the receiving STA may determine the type of the received PPDU as non-HT, HT, and VHT PPDU based on the following items. For example, if 1) the first symbol after the L-LTF signal is BPSK, and 2) the L-SIG repeating RL-SIG is not detected, the received PPDU will be determined as non-HT, HT and VHT PPDU. I can. In addition, even if the receiving STA detects the repetition of RL-SIG, if the result of applying “modulo 3” to the length value of L-SIG is detected as “0”, the receiving PPDU is non-HT, HT and VHT PPDU. It can be judged as.

In the following example, (transmit/receive/uplink/downward) signal, (transmit/receive/uplink/downlink) frame, (transmit/receive/uplink/downlink) packet, (transmit/receive/uplink/downlink) data unit, ( A signal displayed as transmission/reception/up/down) data may be a signal transmitted/received based on the PPDU of FIG. 18. The PPDU of FIG. 18 may be used to transmit and receive various types of frames. For example, the PPDU of FIG. 18 may be used for a control frame. An example of a control frame may include request to send (RTS), clear to send (CTS), Power Save-Poll (PS-Poll), BlockACKReq, BlockAck, NDP (Null Data Packet) announcement, and Trigger Frame. For example, the PPDU of FIG. 18 may be used for a management frame. An example of a management frame may include a Beacon frame, (Re-)Association Request frame, (Re-)Association Response frame, Probe Request frame, and 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 a control frame, a management frame, and a data frame.

19 shows a modified example of the transmitting device and/or the receiving device of the present specification.

Each of the devices/STAs of sub-drawings (a)/(b) of FIG. 1 may be modified as shown in FIG. The transceiver 630 of FIG. 19 may be the same as the transceivers 113 and 123 of FIG. 1. The transceiver 630 of FIG. 19 may include a receiver and a transmitter.

The processor 610 of FIG. 19 may be the same as the processors 111 and 121 of FIG. 1. Alternatively, the processor 610 of FIG. 19 may be the same as the processing chips 114 and 124 of FIG. 1.

The memory 150 of FIG. 19 may be the same as the memories 112 and 122 of FIG. 1. Alternatively, the memory 150 of FIG. 19 may be a separate external memory different from the memories 112 and 122 of FIG. 1.

Referring to FIG. 19, the power management module 611 manages power for the processor 610 and/or the transceiver 630. The battery 612 supplies power to the power management module 611. The display 613 outputs a result processed by the processor 610. Keypad 614 receives input to be used by processor 610. The keypad 614 may be displayed on the display 613. The SIM card 615 may be an integrated circuit used to securely store an IMSI (international mobile subscriber identity) used to identify and authenticate a subscriber in a mobile phone device such as a mobile phone and a computer and a key associated therewith. .

Referring to FIG. 19, the speaker 640 may output a sound-related result processed by the processor 610. The microphone 641 may receive a sound-related input to be used by the processor 610.

Hereinafter, in the present specification, a method of performing communication through a wireless optical communication band according to the IEEE 802.11bb standard may be proposed. An STA capable of performing communication through a wireless optical communication band (hereinafter, referred to as an optical communication STA) may perform communication through two physical layers. The first physical layer may be a physical layer essentially configured in the optical communication STA. The second physical layer may be a physical layer selectively configured in the optical communication STA.

According to an embodiment, the PPDU transmitted by the optical communication STA through the first physical layer may be composed of a first type of PPDU. According to an embodiment, the PPDU transmitted by the optical communication STA through the second physical layer may be configured as a second type of PPDU.

Hereinafter, for convenience of description, an STA that transmits a PPDU of a first format or a second format may be referred to as a transmitting STA. In addition, an STA that receives a PPDU of the first type or the second type may be referred to as a receiving STA.

Hereinafter, a first physical layer and a second physical layer may be described.

(1) 1st Physical layer and 1st type of PPDU

A. The first physical layer may be configured as shown in FIG. 20.

20 is a diagram for describing a first physical layer.

Referring to FIG. 20, in the first physical layer, an additional module (or circuit) for wireless optical communication may be configured in a physical layer according to the conventional IEEE 802.11 standard. The first physical layer is an IFFT (Inverse Fast Fourier Transform) module (or circuit) (2010), CP (Cyclic Prefix) module (or circuit) (2020), Up-conversion module (or circuit (circuit) )) 2030, a Real (or Re(.)) module (or circuit) 2040 or a Light Emitting Diode (LED) module (or circuit) 2050.

According to an embodiment, the first physical layer may additionally include an up-conversion module 2030 and/or an LED module 2050 to a conventional IEEE 802.11 physical layer.

The Inverse Fast Fourier Transform (IFFT) module 2010 may be a module for performing an IFFT process on data. The CP module 2020 may be a module for adding a cyclic prefix to data on which IFFT has been performed. The up-conversion module 2030 may be a module for changing a frequency to a positive number. The Real (or Re(.)) module 2040 may be a module for removing an imaginary part and obtaining only a real part. The LED module 2050 may be a module for transmitting data through an LED device.

The transmitting STA may perform an operation of transmitting data through the LED device through the first physical layer. In addition, the receiving STA may acquire data transmitted through the LED device through the first physical layer.

B. The first physical layer may be configured based on a physical layer of the conventional IEEE 802.11 standard. Therefore, by adding at least one module (or circuit) to the chipset according to the IEEE 802.11 standard, there is an effect that a chipset in which the first physical layer is implemented can be produced.

C. However, since the first physical layer is not optimized for the optical communication band, there is a disadvantage that performance may be degraded.

D. As described above, the PPDU transmitted through the first physical layer may be composed of a first type of PPDU.

21 shows an example of a PPDU of the first type.

Referring to Figure 21, the first type of PPDU (2100) may include a legacy preamble (2110), legacy PHY preamble (2120) or legacy PHY data (2130).

The legacy preamble 2110 may include an L-STF 2111, an L-LTF 2112 or an L-SIG (or an L-SIG field) 2113. Legacy PHY preamble (2120) is RL-SIG (or RL-SIG field) (2121), HE-SIGA (or HE-SIGA field) (2122), HE-SIGB (or HE-SIGB field) (2123) or HE -STF (2124) may be included. The legacy PHY data 2130 may include HE-DATA 2131.

Legacy preamble 2110 may be configured identically in all IEEE 802.11 standard physical layers. If the IEEE 802.11ax standard is used as the baseline, the PPDU 2100 of the first type may be configured in the same manner as the PPDU structure according to the IEEE 802.11ax standard. Therefore, the PPDU 2100 of the first format is L-SIG (2121), HE-SIGA (2122), HE-SIGB (2123), HE-STF (2124) or HE-DATA (after Legacy preamble (2110)) 2131) may be included.

According to an embodiment, before passing through the LED module 2050 of FIG. 20, the PPDU 2100 of the first type of 20 MHz bandwidth may be configured like a physical layer according to the conventional IEEE 802.11 standard. After passing through the LED module 2050, the first type of PPDU 2100 may be transmitted in the actual optical communication band.

(2) 2nd Physical layer and 2nd type PPDU

A. The second physical layer may be optimized in consideration of the characteristics of the optical communication band. Accordingly, the performance of the second physical layer may be higher than that of the first physical layer.

B. However, since the second physical layer cannot use the physical layer according to the existing IEEE 802.11 standard, the second physical layer needs to be additionally implemented.

C. As described above, the PPDU transmitted through the second physical layer may be composed of a second type of PPDU.

22 shows an example of a second type of PPDU.

Referring to FIG. 22, the second type of PPDU 2200 may include a legacy preamble 2210, an LC-optimized PHY preamble 2220, or an LC-optimized PHY data 2230.

The legacy preamble 2210 may include an L-STF 2211, an L-LTF 2212 or an L-SIG 2213. The legacy preamble 2210 may be configured in the same manner as the PPDU of the first type for coexistence with the first physical layer.

In the second type of PPDU 2200, a field after the legacy preamble 2210 may be configured as a field specialized for optical communication. For example, LC-optimized PHY preamble (2220) may include LC-STF (2221), LC-LTF (2222), LC-SIG (or LC-SIG field) (2223) or LC-ATF (2224). I can. In addition, in the PPDU 2200 of the second type, after the LC-optimized PHY preamble 2220, the LC-DATA 2231 may be configured.

Hereinafter, in the present specification, a method for performing communication in an optical communication band may be proposed based on a first physical layer and a second physical layer according to the IEEE 802.11bb standard.

In the following specification, for convenience of description, the transmitting STA may be described as an AP, which is an example of the transmitting STA. In addition, the receiving STA may be described as an STA.

23 is a diagram for describing an example of wireless optical communication.

When wireless optical communication (or wireless broadband communication) is performed, characteristics of a downlink and an uplink may be different. According to an embodiment, the AP 2310 may include LED lighting (or LED circuit). For example, LED lighting may be installed on a ceiling or the like. According to an embodiment, the STA 2320 connected to the AP 2310 may include a smartphone or a laptop computer.

Since the AP 2310 performs communication through LED lighting, downlink transmission may be performed through visible light. In other words, the AP 2310 may perform downlink transmission through the visible light band. For example, the visible light band may include a band of 400 THz to 789 THz. In downlink transmission through visible light, the transmission range is wide.

The STA 2320 may perform uplink transmission through infrared. In other words, the STA 2320 may perform uplink transmission through the infrared band. For example, the infrared band may include 60 THz to 400 THz band. In the case of uplink transmission through infrared, the transmission range is narrow.

That is, the AP 2310 may transmit a signal to the STA 2320 over a wide range. The STA 2320 may transmit a signal to the AP 2310 in a narrow range.

24 is a diagram for describing an example in which a collision occurs between STAs connected to an AP.

Referring to FIG. 24, an AP 2410 may be connected to STA 1 2420 and STA 2 2430. The AP 2410 may have a different transmission range from the STA 1 2420 and STA 2 2430. Since STA 1 2420 or STA 2 2430 transmits a packet (or signal) to the AP 2410 through a narrow range, STA 1 2420 or STA 2 2430 transmits packets transmitted by each other. It may not be possible to confirm. Therefore, it may be difficult for a Carrier Sense Multiple Access (CSMA) according to the conventional IEEE 802.11 standard to operate normally.

According to an embodiment, during downlink transmission, STA 1 2420 and STA 2 2430 may check a packet transmitted by the AP 2410. For example, STA 1 2420 may check a packet transmitted from AP 2410 to STA 2 2430. For another example, the STA 2 2430 may check a packet transmitted from the AP 2410 to the STA 1 2420. Since STA 1 2420 and STA 2 2430 can check packets transmitted from the AP 2410, collision can be prevented.

According to an embodiment, during uplink transmission, STA 1 2420 and STA 2 2430 cannot check packets transmitted by each other. For example, STA 1 2420 cannot check a packet transmitted from STA 2 2430 to AP 2410. For another example, STA 2 2430 cannot check a packet transmitted from STA 1 2420 to AP 2410. Accordingly, when STA 1 2420 and STA 2 2430 transmit uplink, collision may occur.

For example, STA 1 2420 and STA 2 2430 may simultaneously transmit a packet (or signal) to the AP 2410 through an uplink. Signals transmitted from STA 1 2420 and STA 2 2430 may collide with each other.

As another example, the STA 1 2420 may transmit a first packet (or a first signal) to the AP 2410 through an uplink. Thereafter, the STA 2 2430 may transmit a second packet (or a second signal) to the AP 2410 through an uplink. In this case, collision between the first packet and the second packet may occur.

In order to prevent collision in uplink transmission, the IEEE 802.11 standard defines an RTS frame and/or a CTS frame. Therefore, the RTS frame and/or the CTS frame can be applied to wireless optical communication transmission. A detailed operation for this may be described with reference to FIG. 25.

25 is a diagram for explaining a method for preventing collision in uplink transmission.

Referring to FIG. 25, an AP 2510 may be connected to STA 1 2520 and STA 2 2530. STA 1 2520 or STA 2 2530 may transmit an RTS frame to the AP 2510 before transmitting data. The AP 2510 may receive the RTS frame. The AP 2510 may transmit a CTS frame based on the RTS frame. The CTS frame may be received by all STAs (STA 1 2520 or STA 2 2530) connected to the AP 2510. Therefore, when the RTS frame and/or the CTS frame is applied to wireless optical communication, there is an effect of preventing collision.

According to an embodiment, in the IEEE 802.11bb standard (hereinafter, LC (Light Communication)), an RTS frame and/or a CTS frame may be used only for an uplink.

However, in the LC standard, two physical layers may be defined. Therefore, in the LC standard, unlike the conventional standard, the RTS frame and/or the CTS frame exchange process may be set differently. Hereinafter, in an LC standard in which two physical layers are used, a method for preventing collision between STAs may be proposed.

In the following embodiment, it may be assumed that the common part of the first type PPDU and the second type PPDU does not exist. For example, the STA in which the first physical layer is implemented may not be able to decode the PPDU of the second type. In addition, the STA in which the second physical layer is implemented may not be able to decode the PPDU of the first type. However, all of the 1/2th Physical layer may be implemented in the AP. Accordingly, the AP can transmit and receive all of the 1/2 type PPDU.

26 is a diagram for describing an embodiment for preventing collision between STAs through an RTS/CTS frame.

Referring to FIG. 26, an AP 2600 may be connected to STA 1 2610 and STA 2 2620. STA 1 2610 and STA 3 2630 may support/include/use the first physical layer. That is, STA 1 2610 and STA 3 2630 may both transmit and receive signals (eg, PPDU of the first type) transmitted through the first physical layer. The AP 2600 may support/include/use a first physical layer and a second physical layer. That is, the AP 2600 may transmit/receive all signals (eg, PPDUs of the 1/2 format) transmitted through the 1/2 physical layer.

In FIG. 26, P1 may represent a frame transmitted through the first physical layer. The STA 1 2610 may transmit the RTS frame 2611 to the AP 2600 before transmitting the Data 1 2612. The AP 2600 may transmit the CTS frame 2601 to the STA 1 2610 in response to the RTS frame 2611. STA 1 2610 may receive the CTS frame 2601.

In addition, STA 3 2630 may also receive the CTS frame 2601. STA 3 2630 may confirm that STA 1 2610 is going to transmit data to AP 2600 based on the CTS frame 2601. Accordingly, the STA 3 2630 may set the designated time as a Network Allocation Vector (NAV) to prevent collision based on the CTS frame 2601.

For example, the STA 3 2630 may set a Network Allocation Vector (NAV) based on the CTS frame 2601 until the transmission of Data 1 2612 is completed. For example, the STA 3 2630 may set the NAV until the transmission of the ACK frame 2602 for the Data 1 2612 is completed based on the CTS frame 2601. By setting a Network Allocation Vector (NAV) until the transmission of Data 1 2612 is completed in STA 3 2630, there is an effect of protecting a channel and preventing collision.

STA 3 2630 may start uplink transmission after NAV ends. The STA 3 2630 may transmit the RTS frame 2631 to the AP 2600 before transmitting the Data 2 2263. The AP 2600 may transmit the CTS frame 2603 to the STA 3 2630 in response to the RTS frame 2631. STA 3 2630 may receive a CTS frame 2603.

In addition, STA 1 2610 may also receive the CTS frame 2603. STA 1 2610 may set a Network Allocation Vector (NAV) based on the CTS frame 2603 until data 2 2263 transmission is completed. For example, the STA 1 2610 may set the NAV until the transmission of the ACK frame 2604 for the Data 2 2263 is completed based on the CTS frame 2603.

Accordingly, before transmitting uplink data (eg, Data 1 (2612), Data 2 (2632)), STA 1 (2610) and STA 3 (2630) transmit RTS frames 2611 and 2631 with the AP 2600. ) Or CTS frames 2601 and 2603 may be exchanged. When performing the exchange process of the RTS frames 2611 and 2631 or the CTS frames 2601 and 2603, there is an effect of preventing collision with other STAs.

27 is a diagram for describing an example in which a collision appears between STAs.

Referring to FIG. 27, unlike FIG. 26, when STA 1 2710 and STA 2 2720 are configured with different physical layers, collision may occur. The AP 2700 may be connected to STA 1 2710 and STA 2 2720.

STA 1 2710 may support/include/use the first physical layer. STA 2 2720 may support/include/use the second physical layer. That is, STA 1 2710 may transmit and receive all signals (eg, PPDUs of the first type) transmitted through the first physical layer. STA 2 2720 may transmit/receive all signals (eg, PPDUs of the second format) transmitted through the second physical layer. However, STA 1 2710 may not be able to transmit or receive a signal (eg, a second type of PPDU) transmitted through the second physical layer. STA 2 2720 may not be able to transmit/receive a signal (eg, a first type of PPDU) transmitted through the first physical layer. The AP 2600 may support/include/use a first physical layer and a second physical layer.

According to an embodiment, when the legacy preamble of the PPDU of the second type is omitted, even if the AP 2700 transmits the CTS frames 2701 and 2702, STAs 2710 and 2720 implemented with different physical layers. ) Does not know when data transmission ends, so uplink collision may occur.

In FIG. 27, P1 may represent a frame transmitted through the first physical layer. P2 may indicate that the frame is transmitted through the second physical layer. STA 1 2710 may acquire a channel before STA2 2720 and transmit an RTS frame 2711 to AP 2700.

For example, the RTS frame 2711 may be set as a first type of PPDU. The AP 2700 may transmit the CTS frame 2701 in response to the RTS frame 2711. Since the AP 2700 has received the RTS frame 2711 set as the PPDU of the first format, it may transmit the CTS frame 2701 set as the PPDU of the first format.

Unlike STA 3 2630 of FIG. 26, STA 2 2720 cannot receive the CTS frame 2701. Since STA 2 2720 is implemented/configured as a second physical layer, it cannot receive the CTS frame 2701 transmitted by the AP 2700.

According to an embodiment, since the signal of the AP 2700 is transmitted in a wide range through the visible light band, the STA 2 2720 can confirm that the channel is in a busy state while the CTS frame 2701 is transmitted through channel sensing. have. Accordingly, STA 2 2720 may set the NAV only while the CTS frame 2701 is transmitted.

STA 1 2710 may transmit Data 1 2712 in response to the CTS frame 2701. When STA 1 2710 transmits Data 1 2712, STA 2 2720 cannot confirm transmission of Data 1 2712.

According to an embodiment, since a signal (eg, Data 1 (2712)) transmitted by STA 1 (2710) is transmitted in a narrow range through an infrared band, STA 2 (2720) from STA 1 (2710) The signal to be transmitted cannot be confirmed.

Since STA 2 2720 cannot confirm that Data 1 2712 is being transmitted, STA 2 2720 may transmit an RTS frame 2721 to AP 2700. For example, the RTS frame 2721 may be set as a second type of PPDU. In this case, a collision between Data 1 (2712) and the RTS frame (2721) may occur. Therefore, the transmission of Data 1 (2712) may be broken. In other words, Data 1 (2712) may not be properly transmitted to the AP (2700). Since the AP 2700 has not properly received the Data 1 2712, it may not transmit an ACK frame.

Since the STA 1 2710 has not received the ACK frame for Data 1 2712, it may transmit the RTS frame 2713 to the AP 2700 again. Also, STA 2 2720 cannot check the RTS frame 2713 transmitted from STA 1 2710. STA 2 2720 may also transmit an RTS frame 2722 to the AP 2700. Collision between the RTS frame 2722 and the RTS frame 2713 may occur.

STA 2 2720 may transmit the RTS frame 2722 to the AP 2700 again. The AP 2700 may transmit the CTS frame 2702 in response to the RTS frame 2722. STA 1 2710 may determine that the channel is in a busy state while the CTS frame 2702 is transmitted through channel sensing of the CTS frame 2702. Accordingly, STA 1 2710 may set the NAV only while the CTS frame 2702 is transmitted. Thereafter, similar to the collision between the Data 1 (2712) and the RTS frame 2721, a collision between the Data 2 (2724) and the RTS frame 2714 may occur.

In the following embodiments, various methods for resolving the collision shown in FIG. 27 may be proposed. At least one of the embodiments proposed below may be used.

Embodiment 1

28 is a diagram for explaining a method for preventing collision between frames.

Referring to FIG. 28, the AP 2700 may set a period for a first physical layer (hereinafter, PHY1 duration) and a period for a second physical layer (hereinafter, PHY2 duration). According to an embodiment, the AP 2700 may set the PHY1 duration and the PHY2 duration based on the current network condition. The AP 2700 may transmit a beacon frame at the start time of each section. For example, the AP 2700 may transmit PHY1- Beacons 2801 and 2807 at the start time of the PHY1 duration. As another example, the AP 2700 may transmit the PHY2-Beacon 2804 at the start time of the PHY2 duration.

According to an embodiment, the AP 2700 may transmit the PHY1-Beacon 2801 using the first physical layer. The AP 2700 may transmit information on the PHY1 duration based on the PHY1-Beacon 2801.

STA 1 2710 may acquire information on PHY1 duration based on PHY1-Beacon 2801. Since STA 1 2710 is configured as a first physical layer, uplink data may be transmitted to the AP 2700 during the PHY1 duration. For example, STA 1 2710 may transmit an RTS frame 2811 to AP 2700. STA 1 2710 may receive the CTS frame 2802. STA 1 2710 may transmit Data 2812 to AP 2700 based on CTS frame 2802. STA 1 2710 may receive an ACK frame 2803 in response to Data 2812.

On the other hand, since STA 2 2720 is configured as a second physical layer, it may not receive the PHY1-Beacon 2801. STA 2 2720 may wait without transmitting and receiving a signal for the duration of PHY1.

STA 2 2720 may acquire information on PHY2 duration based on PHY2-Beacon 2804. Since STA 2 2720 is configured as a second physical layer, uplink data may be transmitted to the AP 2700 during the PHY2 duration. For example, STA 2 2720 may transmit the RTS frame 2822 to the AP 2700. STA 2 2720 may receive the CTS frame 2805. STA 2 2720 may transmit Data 2822 to AP 2700 based on CTS frame 2805. STA 2 2720 may receive an ACK frame 2806 in response to Data 2822.

On the other hand, since STA 1 2710 is configured as the first physical layer, it may not receive the PHY2-Beacon 2804. STA 1 2710 may wait without transmitting and receiving a signal for the duration of PHY2.

PHY1-Beacon (2801, 2807) and PHY2-Beacon (2804) indicating the start of the PHY1 duration and PHY2 duration may be changed to a management frame other than the beacon frame.

According to an embodiment, the PHY1- Beacons 2801 and 2807 may include various types of information. For example, PHY1-Beacon (2801, 2807) may include some or all of the following information. An example in which the PHY1- Beacons 2801 and 2807 include some or all of the following information may be applied not only to the first embodiment, but also to various embodiments described after the first embodiment.

-First information on PHY1 Duration: The AP 2700 may transmit information on a period in which the STA 1 2710 supporting the first physical layer can perform uplink transmission (ie, PHY1 duration). The first information on the PHY1 Duration may include information on the length of the PHY1 Duration or information on the repetition period of the PHY1 Duration.

-Second information about PHY2 Duration: The AP 2700 is in a period in which STAs supporting the first physical layer (eg, STA 1 2710) cannot perform uplink transmission (ie, PHY2 duration). You can send information about it. In other words, the AP 2700 transmits information on a period in which STAs supporting the second physical layer (eg, STA 2 2720) can perform uplink transmission (ie, PHY2 duration). I can. The information on the PHY2 Duration may include information on the length of the PHY2 Duration or information on the repetition period of the PHY2 Duration. By transmitting second information about PHY2 Duration to STAs (eg, STA 1 2710) supporting the first physical layer by the AP 2700, the STAs can predict the next PHY1 Duration period. have.

-Information on whether to use the RTS/CTS frame: When uplink data is to be transmitted in the PHY1 Duration, the AP 2700 may transmit information on whether the RTS/CTS frame must be used. Based on whether the RTS/CTS frame is used or not is TRUE (ie, the first value), STA 1 2710 may always transmit uplink data through an RTS/CTS frame exchange process.

According to an embodiment, the PHY2-Beacon 2804 may include various types of information. For example, the PHY2-Beacon 2804 may include some or all of the following information. An example in which the PHY1-Beacon 2804 includes some or all of the following information may be applied not only to the first embodiment, but also to various embodiments described after the first embodiment.

-Third information about PHY1 Duration: The AP 2700 is in a period in which STAs supporting the second Physical layer (eg, STA 2 2720) cannot perform uplink transmission (ie, PHY1 Duration). You can send information about it. In other words, the AP 2700 transmits information about a period in which STAs supporting the first physical layer (eg, STA 1 2710) can perform uplink transmission (ie, PHY1 Duration). I can. The third information on the PHY1 Duration may include information on the length of the PHY1 Duration or information on the repetition period of the PHY1 Duration. By transmitting the third information on the PHY1 Duration to STAs (eg, STA 2 2720) that support the second physical layer by the AP 2700, the STAs can predict the next PHY2 Duration period. have.

-Fourth information on PHY2 Duration: The AP 2700 may transmit section information in which STAs supporting the second physical layer (eg, STA 2 2720) can perform uplink transmission. The fourth information on the PHY2 Duration may include information on the length of the PHY2 Duration or the repetition period of the PHY2 Duration.

-Information on whether to use the RTS/CTS frame: When uplink data is scheduled to be transmitted in the PHY2 Duration, the AP 2700 may transmit information on whether the RTS/CTS frame must be used. Based on whether the RTS/CTS frame is used or not is TRUE (ie, the first value), the STA 2 2720 may always have to transmit uplink data through the RTS/CTS frame exchange process.

Second embodiment

29 is another diagram for explaining a method for preventing collision between frames.

Referring to FIG. 29, unlike the uplink transmission of FIG. 28, in downlink transmission, the AP 2700 may transmit data regardless of PHY1 Duration or PHY2 Duration. For example, in downlink transmission, since a signal is transmitted through a wide range through a visible light band, STA 1 2710 or STA 2 2720 may determine whether a signal that it does not support exists. For example, STA 1 2710 or STA 2 2720 may determine whether the current channel is in a busy state. STA 1 2710 or STA 2 2720 may set the NAV based on the current channel being busy. Therefore, unlike uplink transmission, downlink transmission may have a low risk of interframe collision.

Accordingly, the AP 2700 may transmit a signal regardless of the PHY1 Duration or PHY2 Duration. For example, the AP 2700 may transmit Data 2901 for STA 1 2710 in PHY1 Duration. In addition, the AP 2700 may transmit Data 2902 for STA 2 2720 in PHY1 Duration. Data 2902 for STA 2 2720 may be set as a second type of PPDU.

For another example, the AP 2700 may transmit Data 2902 for STA 2 2720 in PHY2 Duration. In addition, the AP 2700 may transmit Data 2904 for STA 1 2710 in PHY2 Duration. Data 2904 for STA 1 2710 may be set as a first type of PPDU.

Third embodiment

30 is another diagram for explaining a method for preventing collision between frames.

Referring to FIG. 30, an example in which uplink transmission or downlink transmission is performed based on a period (PHY1 Duration or PHY2 Duration) may be described. The AP 2700, STA 1 2710, or STA 2 2720 may perform downlink transmission or uplink transmission in a predetermined interval.

According to an embodiment, the AP 2700 may receive Data 3011 from STA 1 2710 in PHY1 Duration. AP 2700 may transmit Data 3001 to STA 1 2710 in PHY1 Duration.

According to an embodiment, the AP 2700 may receive Data 3021 from STA 2 2720 in PHY2 Duration. The AP 2700 may transmit Data 3021 to STA 2 2720 in PHY2 Duration.

According to an embodiment, since STA 2 2720 cannot transmit and receive signals during PHY1 Duration, it may operate in a low power mode. Since STA 1 2710 cannot transmit/receive signals in PHY2 Duration, it can operate in a low power mode. Accordingly, STA 1 2710 or STA 2 2720 may operate in a low power mode in a period in which they cannot transmit and receive signals. STA 1 (2710) or STA 2 (2720) has an effect of reducing power consumption by operating in a low power mode in a period in which it cannot transmit and receive signals. However, the latency of downlink data may increase.

Embodiment 4

The fourth embodiment may be an embodiment in which the second embodiment or the third embodiment is combined. Referring back to the second embodiment, downlink transmission may be possible to STAs supporting the second physical layer in PHY1 Duration. Referring back to the third embodiment, downlink transmission may not be possible to STAs supporting the second physical layer in PHY1 Duration.

In the fourth embodiment, downlink transmission may be allowed to STAs supporting the second physical layer in part of the PHY1 Duration. STA 1 and STA 2 may transmit information on Off duration or On duration to the AP. Off duration may include a period in which the STA operates in a low power mode. The STA may not be able to transmit and receive signals within the Off duration. Off duration may start together when a PHY duration not used by the STA starts. Off duration may be included in the PHY duration. In other words, the length of the Off duration may be set shorter than the length of the PHY duration. A section of the PHY duration excluding the Off duration may be set as On duration.

According to an embodiment, the AP may transmit downlink data to an STA using a physical layer related to each PHY duration in each PHY duration. However, when the AP transmits downlink data to an STA that does not use a physical layer related to each PHY duration in each PHY duration, if the corresponding terminal is an Off duration, it may wait until the On duration is reached and then transmit the downlink data.

According to the fourth embodiment, there is an effect of reducing power consumption compared to the second embodiment. According to the fourth embodiment, there is an effect that the latency of downlink data can be reduced compared to the third embodiment.

A specific example of the fourth embodiment may be described with reference to FIG. 31.

31 is another diagram for explaining a method for preventing collision between frames.

Referring to FIG. 31, STA 2 2720 may set an Off duration 3121 or an On duration 3122 within PHY1 Duration 3101. The STA 2 2720 may transmit information on the Off duration 3121 or the On duration 3122 to the AP 2700.

According to an embodiment, the STA 2 2720 may operate in a sleep mode/low power mode in an Off duration 3121. STA 2 2720 may not transmit/receive a signal in the Off duration 3121. The AP 2700 may transmit/receive data encoded through the first physical layer to the STA 1 2710 in the Off duration 3121.

According to an embodiment, the AP 2700 may transmit data to the STA 2 2720 in the On duration 3122. The AP 2700 may transmit data encoded through the second physical layer to the STA 2 2720 even within the PHY1 Duration 3101.

When there is downlink data to be transmitted to STA 2 2720, the AP 2700 may wait in the Off duration 3121. The AP 2700 may transmit the downlink data to the STA 2 2720 in the On duration 3122.

Although not shown, STA 1 2710 may also set Off duration or On duration within PHY2 duration 3102. Within the Off duration of the PHY2 duration 3102, the STA 1 2710 may operate in a sleep mode/low power mode. Within the On duration of the PHY2 duration 3102, the STA 1 2710 may receive encoded data from the AP 2700 through the first physical layer.

Embodiment 5

When transmitting downlink data, the STA and the AP may select one of the second method to which the second embodiment is applied to the fourth method to which the fourth embodiment is applied. The STA and the AP may determine one of the second to fourth methods through an association process or an Operating mode indication process. The following information may be exchanged during an association process or a management frame transmission/reception process after the association process.

-Downlink Power save mode support: The AP may transmit information on supported embodiments among the second to fourth methods. The AP may transmit information on the currently used embodiment.

-Downlink Power save mode request: After determining/selecting one of the second to fourth methods, the STA may request the AP for the determined/selected method.

-Downlink Power save mode response: The AP may determine a downlink traffic situation currently being transmitted. The AP may determine whether to approve the method requested by the STA and then transmit it to the STA.

-Off duration, On duration information: When the STA requests the AP to determine/select one of the second to fourth methods, the Off duration and On duration information may also be transmitted to the AP.

Hereinafter, when the above-described embodiments are applied, the operation of the AP and the STA may be described.

32 is a flowchart illustrating an operation of an AP.

Referring to FIG. 32, in step S3210, the AP may determine PHY1 duration and PHY2 duration. The AP may determine the length of the PHY1 duration or the repetition period of the PHY1 duration. In addition, the AP may determine the length of the PHY2 duration or the repetition period of the PHY2 duration. For example, the PHY1 duration may include a period in which an STA supporting the first physical layer can perform uplink transmission. For another example, the PHY2 duration may include a period in which an STA supporting the second physical layer can perform uplink transmission.

In step S3220, the AP may transmit a PHY1 Beacon. The AP may transmit a PHY1 Beacon including information on the PHY1 duration to an STA (hereinafter, STA 1) supporting the first physical layer within the PHY1 duration. For example, the PHY1 Beacon may be configured/configured as a first type of PPDU.

According to an embodiment, the PHY1 Beacon may include information about the PHY1 duration and/or information about the PHY2 duration. For example, the information about the PHY1 duration may include information about the length of the PHY1 duration and/or information about the repetition period of the PHY1 Duration. For another example, the information on the PHY2 duration may include information on the length of the PHY2 duration and/or information on the repetition period of the PHY2 Duration. The AP may transmit information on the PHY2 duration so that STA 1 can predict the next PHY1 duration.

In step S3230, the AP may receive uplink data from STA 1 through the first physical layer. For example, the AP may receive an RTS frame from STA 1 within the PHY1 duration. The AP may transmit a CTS frame in response to the RTS frame. The AP may receive uplink data from STA 1 in response to the CTS frame. According to an embodiment, the AP may transmit downlink data to STA 1 through the first physical layer.

In step S3230, the AP may transmit a PHY2 Beacon. The AP may transmit a PHY1 Beacon to an STA (hereinafter, STA 2) supporting the second physical layer within the PHY2 duration, including information on the PHY2 duration. For example, the PHY2 Beacon may be configured/configured with a second type of PPDU.

In step S3240, the AP may receive uplink data from STA 2 through the second physical layer. For example, the AP may receive an RTS frame from STA 2 within the PHY2 duration. The AP may transmit a CTS frame in response to the RTS frame. The AP may receive uplink data from STA 2 in response to the CTS frame. According to an embodiment, the AP may transmit downlink data to STA 2 through the second physical layer.

33 is a flowchart for describing an operation of an STA.

Referring to FIG. 33, in step S3310, the STA may confirm that uplink data is generated. For example, the STA may confirm that the uplink data has entered the MAC buffer. The STA may support either the first physical layer or the second physical layer. For convenience of description, the following steps may be described on the assumption that the STA supports the first physical layer.

In step S3320, the STA may determine whether the current period is PHY1 duration. Since the STA supports the first physical layer, uplink data may be transmitted to the AP in the PHY1 duration. Accordingly, in order to transmit uplink data, the STA may determine whether the current period is the PHY1 duration.

In step S3330, if the current period is not the PHY1 duration, the STA may wait for uplink data transmission until the PHY1 duration. For example, the STA may confirm that the current section is PHY2 duration. The STA may wait for uplink data transmission until the PHY2 duration ends. According to an embodiment, when the STA is not the PHY1 duration, the STA may operate in a sleep mode/low power mode.

In step S3340, the STA may transmit uplink data. According to an embodiment, the STA may transmit uplink data based on the PHY1 duration. For example, the STA may transmit uplink data to the AP based on the current period being the PHY1 duration. For another example, after waiting for the duration of PHY2, the STA may transmit uplink data to the AP based on the start of the duration of PHY1.

According to an embodiment, in order to transmit uplink data, the STA may transmit an RTS frame to the AP within a PHY1 duration. The STA may receive the CTS frame from the AP based on the RTS frame. The STA may transmit uplink data to the AP based on the CTS frame.

In step S3350, the STA may receive an ACK frame based on uplink data. The STA can confirm that uplink data has been transmitted to the AP based on the ACK frame.

Embodiment 6

When one of the first physical layer or the second physical layer is designated as an essential physical layer (hereinafter, mandatory physical layer), the sixth embodiment may be applied.

Hereinafter, an example in which the first physical layer is designated/set as a mandatory physical layer may be described. In this case, STAs (eg, non-AP STAs) may always include/support the first physical layer. The STAs may selectively include/support a second physical layer. The AP may always include/support the first physical layer. In addition, the AP may selectively include/support a second physical layer. However, hereinafter, an example in which both the AP and the STA include both the first physical layer and the second physical layer may be described.

According to the sixth embodiment, the scanning process, the authentication process, or the association process may be performed only in the first physical layer that is the mandatory physical layer. A specific example of the sixth embodiment may be described with reference to FIG. 34.

34 is a diagram for explaining an example of an association process.

Referring to FIG. 34, the AP 3400 and the STA 3410 may include both a first physical layer and a second physical layer. Among the first physical layer and the second physical layer, a first physical layer may be designated/set as a mandatory physical layer.

The AP 3400 may perform a scanning process, an authentication process, or an association process through a first physical layer that is a mandatory physical layer. For example, the AP 3400 may transmit the PHY1 Beacon 3401 through the first physical layer. 34 illustrates an example in which the AP 3400 performs passive scanning through the PHY1 Beacon 3401, but is not limited thereto. The AP 3400 may also perform active scanning.

The STA 3410 may perform an association process through the first physical layer. For example, the STA 3410 may transmit an Association Request frame 3411 to the AP 3400. The AP 3400 may transmit an ACK frame 3402 in response to the Association Request frame 3411. The AP 3400 may transmit an Association Response frame 3403 to the STA 3401 based on the Association Request frame 3411. The STA 3401 may transmit an ACK frame 3412 in response to the Association Response frame 3403.

The STA 3410 may transmit UL Data 3413 to the AP 3400 after performing the association process. For example, the STA 3410 may transmit UL Data 3413 to the AP 3400 through the second physical layer. The AP 3400 may transmit an ACK frame 3404 to the STA 3401 through the second physical layer in response to the UL Data 3413. Although not shown, the AP 3400 may transmit downlink data to the STA 3410 through the second physical layer.

In order to perform the above-described process, the Association Request frame 3411 and/or the Association Response frame 3403 may include the following information.

-PHY2 Channel information: PHY 2 Channel information may include information on a channel in which the second physical layer operates.

-PHY2 Capability information: PHY2 Capability information may include information on the capability of the second physical layer. For example, the PHY2 Capability information may include information on whether to support a transmission speed of the AP 3400 and/or the STA 3410, a modulation scheme, a maximum/minimum transmit power, and a short GI support.

-Transition delay information: Transition delay information may include information on a time delay value when switching from the first physical layer to the second physical layer. Further, the transition delay information may include information on a time delay value when switching from the second physical layer to the first physical layer. After performing the association process, the AP 3400 and the STA 3410 may transmit data after the delay interval. In order to transmit information on the delay interval, the AP 3400 and/or the STA 3410 may include transition delay information in the Association Request frame 3411 and/or the Association Response frame 3403.

According to an embodiment, when a beacon is transmitted only through the first physical layer, the AP 3400 and/or the STA 3410 may transmit information about a time when data transmission is possible before/after the beacon transmission time. .

-PHY2 Beacon information: The PHY2 Beacon information may include information on whether or not a Beacon is transmitted through the second physical layer and/or information on a Beacon period. According to an embodiment, when the Beacon is not transmitted through the second physical layer, the STA 3410 may need to change the mode to periodically use the first physical layer in order to receive the Beacon.

According to an embodiment, a Beacon may be transmitted through the second physical layer. The PHY2 Beacon information may include information indicating that Beacon can be transmitted through the second Physical layer. Based on the PHY2 Beacon information, the STA 3410 may not change the mode to periodically use the first physical layer to receive the Beacon. The STA 3410 may receive a beacon through the second physical layer.

It may be exemplary that the Association Request frame 3411 and/or the Association Response frame 3403 may include the above-described information. According to an embodiment, the above-described information may be included in various frames. For example, the above-described information may be included in not only the Association Request frame 3411 and the Association Response frame 3403, but also a Probe Request/Response frame, an Authentication Request/Response frame, and/or a Beacon frame.

Embodiment 7

In the seventh embodiment, the second to fifth embodiments may be combined with the sixth embodiment. One of the first physical layer or the second physical layer may be designated as an essential physical layer (hereinafter, a mandatory physical layer). Hereinafter, an example in which the first physical layer is designated/set as a mandatory physical layer may be described.

According to the seventh embodiment, the AP may transmit information on the PHY1 duration and/or information on the PHY2 duration based on the PHY1 beacon. The STA may identify information on the PHY1 duration and/or the PHY2 duration based on the PHY1 beacon. The STA may transmit data through the second physical layer in the PHY2 duration.

A specific example of the seventh embodiment described above may be described in FIG. 35.

35 is another diagram for explaining a method for preventing collision between frames.

Referring to FIG. 35, an AP 3400 may receive a PHY1 Beacon 3501 from an STA 3410 through a wireless optical communication band. The PHY1 Beacon 3501 may include information about the PHY1 duration and/or information about the PHY2 duration. For example, the PHY1 Beacon 3501 may be transmitted through the first physical layer. In other words, the AP 3400 may transmit the PHY1 Beacon 3501 to the STA 3410 through the first physical layer.

The STA 3410 may operate in the sleep mode in the PHY1 duration. For example, after receiving the PHY1 Beacon 3501, the STA 3410 may set the operation mode of the STA 3410 to the sleep mode within the PHY1 duration.

PHY2 duration may be set after PHY1 duration. In the PHY2 duration, the STA 3410 may transmit UL Data 3511 to the AP 3400. UL Data 3511 may be transmitted through the second physical layer. The STA 3410 may receive the ACK frame 3512 in response to the UL Data 3511.

According to an embodiment, although not shown, the STA 3410 may perform an RTS/CTS frame exchange process in order to transmit the UL Data 3511. For example, the PHY1 Beacon 3501 may include information on whether to use an RTS/CTS frame. The STA 3410 may perform an RTS/CTS frame exchange process based on the PHY1 Beacon 3501.

According to an embodiment, although not shown, the STA 3410 may receive downlink data from the AP 3400 through the second physical layer. According to an embodiment, the STA 3410 may identify information on a physical layer to receive downlink data based on the PHY1 Beacon 3501. The STA 3410 may receive downlink data based on the identified physical layer.

For example, the STA 3410 may determine that the physical layer to receive downlink data is the first physical layer based on the PHY1 Beacon 3501. The STA 3410 does not operate in the sleep mode in the PHY1 duration and may receive downlink data through the first physical layer within the PHY1 duration.

For another example, the STA 3410 may determine that the physical layer for receiving downlink data is the second physical layer based on the PHY1 Beacon 3501. The STA 3410 may operate in the sleep mode during the PHY1 duration. The STA 3410 may receive downlink data through the second physical layer within the PHY2 duration.

36 is a flowchart illustrating another operation of the AP.

Referring to FIG. 36, in step S3610, the AP may transmit a PHY1 Beacon. For example, the AP may transmit a PHY1 Beacon based on a passive scanning process. According to an embodiment, the AP may transmit the PHY1 Beacon through the first physical layer.

In step S3620, the AP may perform an association process with the STA. For example, the AP may receive an Association Request frame from the STA based on the PHY1 Beacon. The AP can transmit an Association Response frame in response to the Association Request frame. For example, an Association Request frame or an Association Response frame may be transmitted and received through a first physical layer. In other words, the AP may perform an association process with the STA based on the first physical layer. The association process may be related to step S330 of FIG. 3.

In step S3630, the AP may transmit downlink data through the second physical layer. The AP may receive uplink data through the second physical layer. In other words, the AP may transmit and receive data with the STA based on the second physical layer.

In step S3640, the AP may transmit the PHY1 Beacon again. The AP may periodically transmit the PHY1 Beacon based on a preset period.

37 is a flowchart for explaining another operation of the STA.

Referring to FIG. 37, in step S3710, the STA may receive a PHY1 Beacon from the AP. For example, the STA may periodically receive the PHY1 Beacon from the AP. For example, the STA may receive the PHY1 Beacon based on the passive scanning process. According to an embodiment, the STA may receive the PHY1 Beacon through the first physical layer.

In step S3720, the STA may perform an association process with the AP. For example, the STA may transmit an Association Request frame to the AP based on the PHY1 Beacon. The STA may receive an Association Response frame based on the Association Request frame. For example, the Association Request frame or the Association Response frame may be transmitted and received through the first physical layer. In other words, the STA may perform an association process with the AP based on the first physical layer. The association process may be related to step S330 of FIG. 3.

In step S3730, the STA may receive downlink data through the second physical layer. The STA may transmit uplink data through the second physical layer. In other words, the STA may transmit and receive data to and from the AP based on the second physical layer.

In step S3740, the STA may receive a PHY1 Beacon or PHY2 Beacon. For example, the STA may periodically receive PHY1 Beacon or PHY2 Beacon.

38 is a flowchart illustrating an operation of a transmitting STA.

Referring to FIG. 38, in step S3810, a transmitting STA (e.g., APs 2700, 3400) receives a first PPDU of a first format (e.g., STA 1 2710, STA 2 2720). ) Or the STA 3410).

According to an embodiment, the first PPDU may include a frame for establishing a connection with a receiving STA. For example, the first PPDU may include an Association Request/Response frame, a Probe Request/Response frame, an Authentication Request/Response frame, or a Beacon frame.

According to an embodiment, the first PPDU may include information on whether to use the RTS frame and the CTS frame. The transmitting STA may transmit information on whether to use the RTS frame and the CTS frame for receiving uplink data to the receiving STA.

According to an embodiment, the first PPDU of the first type may be transmitted through the first physical layer. The first PPDU of the first format may include a legacy preamble, a legacy PHY preamble, or a data field.

For example, the legacy preamble may include L-STF, L-LTF, or L-SIG. The legacy preamble may be located in front of the first PPDU of the first format. For example, in the legacy preamble, the L-LTF may be set after the L-STF. L-SIG can be set after L-LTF.

For example, the legacy pi preamble may include RL-SIG, HE-SIGA, HE-SIGB, or HE-STF. The legacy pie preamble may be set after the legacy preamble. For example, in the legacy pie preamble, HE-SIGA may be set after RL-SIG. HE-SIGB may be set after HE-SIGA. HE-STF may be set after HE-SIGB.

For example, a data field may be set after the legacy pie preamble.

According to an embodiment, the transmitting STA may transmit the first PPDU of the first type to the receiving STA through the wireless optical communication band. For example, the transmitting STA and the receiving STA may operate in the visible and infrared bands of 60 THz to 789 THz.

According to an embodiment, the transmitting STA may transmit the first PPDU of the first type to the receiving STA through the visible light band. For example, the visible light band may include a band of 400 THz to 789 THz.

According to an embodiment, the first PPDU may include information about the first section or information about the second section. For example, the transmitting STA may communicate with the receiving STA based on the first format during the first period. For another example, the transmitting STA may communicate with the receiving STA based on the second format during the second period. In other words, the transmitting STA may transmit and receive the first type of PPDU (eg, the first PPDU) during the first period. The transmitting STA may transmit and receive a second type of PPDU (eg, a second PPDU or a third PPDU) during the second period.

In step S3820, the transmitting STA may receive a second PPDU of the second format from the receiving STA.

According to an embodiment, the transmitting STA may receive data from the receiving STA based on the information on the second period. For example, the transmitting STA may receive the RTS frame from the receiving STA based on the first PPDU within the second period. The transmitting STA may transmit the CTS frame to the receiving STA in the second period based on the RTS frame. The transmitting STA may receive the second PPDU within the second period, based on the CTS frame.

According to an embodiment, the transmitting STA may receive the second PPDU of the second format from the receiving STA through a wireless optical communication band. For example, the transmitting STA may receive the second PPDU of the second format from the receiving STA through the infrared band. For example, the infrared band may include 60 THz to 400 THz band.

According to an embodiment, the transmitting STA may transmit data to the receiving STA based on the information on the second interval. For example, the transmitting STA may transmit a third PPDU of the second type to the receiving STA through the wireless optical communication band within the second period. As an example, the transmitting STA may transmit a third PPDU of the second format to the receiving STA through the visible light band.

39 is a flowchart illustrating an operation of a receiving STA.

Referring to FIG. 39, in step S3910, a receiving STA (e.g., STA 1 2710, STA 2 2720, or STA 3410) transmits a first PPDU of a first format (for example, It can be received from the AP (2700, 3400).

According to an embodiment, the first PPDU may include an Association Request/Response frame, a Probe Request/Response frame, an Authentication Request/Response frame, or a Beacon frame. According to an embodiment, the receiving STA may establish a connection with the transmitting STA based on the first PPDU.

According to an embodiment, the first PPDU may include information on whether to use the RTS frame and the CTS frame. The receiving STA may receive information on whether to use the RTS frame and the CTS frame for receiving uplink data from the transmitting STA.

According to an embodiment, the first PPDU of the first type may be transmitted through the first physical layer. The first PPDU of the first format may include a legacy preamble, a legacy PHY preamble, or a data field.

For example, the legacy preamble may include L-STF, L-LTF, or L-SIG. The legacy preamble may be located in front of the first PPDU of the first format. For example, in the legacy preamble, the L-LTF may be set after the L-STF. L-SIG can be set after L-LTF.

For example, the legacy pi preamble may include RL-SIG, HE-SIGA, HE-SIGB, or HE-STF. The legacy pie preamble may be set after the legacy preamble. For example, in the legacy pie preamble, HE-SIGA may be set after RL-SIG. HE-SIGB may be set after HE-SIGA. HE-STF may be set after HE-SIGB. Specific field names of the above-described fields may be variously set.

For example, a data field may be set after the legacy pie preamble.

According to an embodiment, the receiving STA may receive the first PPDU of the first type from the transmitting STA through the wireless optical communication band. For example, the transmitting STA and the receiving STA may operate in the visible and infrared bands of 60 THz to 789 THz.

According to an embodiment, the receiving STA may receive the first PPDU of the first type from the transmitting STA through the visible light band. For example, the visible light band may include a band of 400 THz to 789 THz.

In step S3920, the receiving STA may identify information on the first interval or information on the second interval based on the first PPDU. For example, the receiving STA may communicate with the transmitting STA based on the first format during the first period. For another example, the receiving STA may communicate with the transmitting STA based on the second format during the second period. In other words, the receiving STA may transmit and receive a first type of PPDU (eg, a first PPDU) during the first period. The receiving STA may transmit and receive a second type of PPDU (eg, a second PPDU or a third PPDU) during the second period.

In step S3930, the receiving STA may transmit a second PPDU of the second format to the transmitting STA.

According to an embodiment, the second PPDU of the second type may be transmitted through the second physical layer. The second PPDU of the second format may include a legacy preamble, an LC-optimized PHY preamble, or a data field.

For example, the legacy preamble may include L-STF, L-LTF, or L-SIG. The legacy preamble may be located in front of the first PPDU of the first format. For example, in the legacy preamble, the L-LTF may be set after the L-STF. L-SIG can be set after L-LTF.

For example, the LC optimized pie preamble can include LC-STF, LC-LTF, LC-SIG or LC-ATF. The LC optimized pi preamble can be set after the legacy preamble. For example, in the LC optimized pie preamble, an LC-LTF may be set after the LC-STF. LC-SIG can be set after LC-LTF. LC-ATF can be set after LC-SIG. Specific field names of the above-described fields may be variously set.

For example, a data field may be set after the LC optimization pie preamble.

According to an embodiment, the receiving STA may check whether a request to send (RTS) frame and a clear to send (CTS) frame are used to transmit the second PPDU. For example, the receiving STA may check information on whether to use the RTS frame and the CTS frame based on the first PPDU. After receiving the CTS frame, the receiving STA may transmit a second PPDU to the transmitting STA.

According to an embodiment, the receiving STA may transmit the second PPDU of the second format to the transmitting STA through the wireless optical communication band. For example, the receiving STA may receive the second PPDU of the second format from the transmitting STA through the infrared band. For example, the infrared band may include 60 THz to 400 THz band.

According to an embodiment, the receiving STA may transmit data to the transmitting STA based on the information on the second interval. For example, the receiving STA may transmit a second PPDU of the second format to the transmitting STA within the second period.

According to an embodiment, the receiving STA may set the operation mode of the receiving STA to the sleep mode based on information on the first period. For example, the receiving STA may set the operation mode of the receiving STA to the sleep mode within the first period.

According to an embodiment, the receiving STA may receive the third PPDU of the second format from the transmitting STA through the wireless optical communication band, based on the information on the first section. For example, the third PPDU may be received through a visible light band.

The technical features of the present specification described above can be applied to various devices and methods. For example, the technical features of the present specification described above 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 may be 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. , May be implemented based on the processor 610 and the memory 620 of FIG. 19. For example, the apparatus of the present specification acquires a first physical layer protocol data unit (PPDU) of a first type from a transmitting STA through a wireless optical communication band, and based on the first PPDU, information on a first section Or, identify (identify) information about the second section, wherein the first section includes a section for communicating with the transmitting STA based on the first format, and the second section is based on the second format. It includes a section for communicating with the transmitting STA, and may be configured to transmit the second PPDU of the second format to the transmitting STA through the wireless optical communication band, based on information on the second section.

Technical features of the present specification may be implemented based on a computer readable medium (CRM). For example, the CRM proposed by the present specification includes: obtaining a first physical layer protocol data unit (PPDU) of a first type from a transmitting STA through a wireless optical communication band; Based on the first PPDU, identify information on a first section or information on a second section, wherein the first section includes a section for communicating with the transmitting STA based on the first format. And, the second period including a period for communicating with the transmitting STA based on a second format; And transmitting the second PPDU of the second format to the transmitting STA through the wireless optical communication band, based on the information on the second section, to store instructions for performing operations. I can. Instructions stored in the CRM of the present specification may be executed by at least one processor. At least one processor related to the CRM of 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 technical features of the present specification described above can be applied to various applications or business models. For example, the above-described technical features may be applied for wireless communication in a device supporting artificial intelligence (AI).

Artificial intelligence refers to the field of researching artificial intelligence or the methodology to create it, and machine learning (Machine Learning) refers to the field of researching methodologies to define and solve various problems dealt with in the field of artificial intelligence. do. Machine learning is also defined as an algorithm that improves the performance of a task through continuous experience.

An artificial neural network (ANN) is a model used in machine learning, and may refer to an overall model with problem-solving capability, which is composed of artificial neurons (nodes) that form a network by combining synapses. The artificial neural network may be defined by a connection pattern between neurons of different layers, a learning process for updating model parameters, and an activation function for 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 neurons and synapses connecting neurons. In an artificial neural network, each neuron can output a function of an activation function for input signals, weights, and biases input through synapses.

Model parameters refer to parameters determined through learning, and include weights of synaptic connections and biases of neurons. In addition, hyperparameters refer to parameters that must be set before learning in a machine learning algorithm, and include a learning rate, iteration count, mini-batch size, and initialization function.

The purpose of learning artificial neural networks can be seen as determining model parameters that minimize the loss function. The loss function can be used as an index to determine an optimal model parameter in the learning process of the artificial neural network.

Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning according to the learning method.

Supervised learning refers to a method of training an artificial neural network when a label for training data is given, and a label indicates the correct answer (or result value) that the artificial neural network should infer when training data is input to the artificial neural network. It can mean. Unsupervised learning may refer to a method of training an artificial neural network in a state where a label for training data is not given. Reinforcement learning may mean a learning method in which an agent defined in a certain environment learns to select an action or action sequence that maximizes the cumulative reward in each state.

Among artificial neural networks, machine learning implemented as a deep neural network (DNN) including a plurality of hidden layers is sometimes referred to as deep learning (deep learning), and deep learning is a part of machine learning. Hereinafter, machine learning is used in the sense including deep learning.

In addition, the above-described technical features can be applied to wireless communication of a robot.

A robot may refer to a machine that automatically processes or operates a task given by its own capabilities. In particular, a robot having a function of recognizing the environment and performing an operation by self-determining may be referred to as an intelligent robot.

Robots can be classified into industrial, medical, household, military, etc. depending on the purpose or field of use. The robot may be provided with a driving unit including an actuator or a motor to perform various physical operations such as moving a robot joint. In addition, the movable robot includes a wheel, a brake, a propeller, etc. in a driving unit, and can travel on the ground or fly in the air through the driving unit.

In addition, the above-described technical features may be applied to a device supporting extended reality.

The extended reality collectively refers to Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR). VR technology provides only CG images of real world objects or backgrounds, AR technology provides virtually created CG images on top of real object images, and MR technology is a computer that mixes and combines virtual objects in the real world. It is a graphic technology.

MR technology is similar to AR technology in that it shows real and virtual objects together. However, in AR technology, virtual objects are used in a form that complements real objects, whereas in MR technology, virtual objects and real objects are used with equal characteristics.

XR technology can be applied to HMD (Head-Mount Display), HUD (Head-Up Display), mobile phones, tablet PCs, laptops, desktops, TVs, digital signage, etc., and devices applied with XR technology are XR devices. It can be called as.

The claims set forth herein 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.

Claims (18)

1. In a method performed in a receiving STA (station) of a wireless local area network (LAN) system,

   Receiving a first type of first physical layer protocol data unit (PPDU) from a transmitting STA through a wireless optical communication band;

   Based on the first PPDU, information on the first section or information on the second section is identified (identify),

   The receiving STA communicates with the transmitting STA based on the first format during the first period,

   The receiving STA communicating with the transmitting STA based on a second format during the second period; And

   Transmitting a second PPDU of the second format to the transmitting STA through the wireless optical communication band based on the information on the second section

   Including

   Way.
2. The method of claim 1,

   Setting an operation mode of the receiving STA to a sleep mode based on the information on the first period

   Further comprising

   Way.
3. The method of claim 1,

   Establishing a connection with the transmitting STA based on the first PPDU;

   Further comprising

   Way.
4. The method of claim 1,

   The first PPDU includes a beacon frame

   Way.
5. The method of claim 1,

   Receiving a third PPDU of the second format from the transmitting STA through the wireless optical communication band, based on the information on the first section

   Further comprising

   Way.
6. The method of claim 5,

   The first PPDU and the third PPDU are received through a visible light band of the wireless optical communication band,

   The second PPDU is transmitted through an infrared band of the wireless optical communication band.

   Way.
7. The method of claim 1,

   Based on the first PPDU, checking whether to use a request to send (RTS) frame and a clear to send (CTS) frame to transmit the second PPDU

   Further comprising

   Way.
8. In a method performed in a transmitting STA (station) of a wireless local area network (LAN) system,

   Transmitting a first type of physical layer protocol data unit (PPDU) to the receiving STA through the wireless optical communication band,

   The first PPDU includes information on a first section or information on a second section,

   The transmitting STA communicates with the receiving STA based on the first format during the first period,

   The transmitting STA communicating with the receiving STA based on a second format during the second period; And

   Receiving a second PPDU of the second format from the receiving STA through the wireless optical communication band, based on the information on the second section

   Including

   Way.
9. In a receiving STA used in a wireless local area network (LAN) system, the receiving STA,

   A transceiver for transmitting and receiving radio signals; And

   Including a processor connected to the transceiver, wherein the processor,

   Receiving a first type of physical layer protocol data unit (PPDU) from the transmitting STA through the wireless optical communication band,

   Based on the first PPDU, information on the first section or information on the second section is identified (identify),

   The receiving STA communicates with the transmitting STA based on the first format during the first period,

   The receiving STA communicates with the transmitting STA based on a second format during the second period,

   Set to transmit the second PPDU of the second format to the transmitting STA through the wireless optical communication band based on the information on the second section

   Receiving STA.
10. The method of claim 9, wherein the processor,

    Based on the information on the first period, further configured to set the operation mode of the receiving STA to a sleep mode

    Receiving STA.
11. The method of claim 9, wherein the processor,

    Based on the first PPDU, further configured to establish a connection with the transmitting STA

    Receiving STA.
12. The method of claim 9,

    The first PPDU includes a beacon frame

    Receiving STA.
13. The method of claim 9, wherein the processor,

    Based on the information on the first section, further configured to receive the third PPDU of the second format from the transmitting STA through the wireless optical communication band

    Receiving STA.
14. The method of claim 13,

    The first PPDU and the third PPDU are received through a visible light band of the wireless optical communication band,

    The second PPDU is transmitted through an infrared band of the wireless optical communication band.

    Receiving STA.
15. The method of claim 9, wherein the processor,

    Based on the first PPDU, further configured to check whether to use a request to send (RTS) frame and a clear to send (CTS) frame to transmit the second PPDU

    Receiving STA.
16. In a transmitting STA used in a wireless local area network (LAN) system, the transmitting STA,

    A transceiver for transmitting and receiving radio signals; And

    Including a processor connected to the transceiver, wherein the processor,

    Transmitting a first type of physical layer protocol data unit (PPDU) to the receiving STA through the wireless optical communication band,

    The first PPDU includes information on a first section or information on a second section,

    The transmitting STA communicates with the receiving STA based on the first format during the first period,

    The transmitting STA communicates with the receiving STA based on a second format during the second period,

    Based on the information on the second section, the second PPDU of the second format is configured to be received from the receiving STA through the wireless optical communication band.

    Sending STA.
17. In the at least one computer readable recording medium (computer readable medium) comprising an instruction (instruction) based on execution by at least one processor (processor),

    Obtaining a first type of first physical layer protocol data unit (PPDU) from a transmitting STA through a wireless optical communication band;

    Based on the first PPDU, information on the first section or information on the second section is identified (identify),

    The first section includes a section for communicating with the transmitting STA based on the first format,

    The second period including a period for communicating with the transmitting STA based on a second format; And

    Transmitting a second PPDU of the second format to the transmitting STA through the wireless optical communication band based on the information on the second section

    An apparatus for performing an operation comprising a.
18. In the device used in the wireless LAN system,

    Processor, and

    Including a memory connected to the processor,

    The processor,

    Obtaining a first physical layer protocol data unit (PPDU) of the first type from the transmitting STA through the wireless optical communication band,

    Based on the first PPDU, information on the first section or information on the second section is identified (identify),

    The first section includes a section for communicating with the transmitting STA based on the first format,

    The second section includes a section for communicating with the transmitting STA based on a second format,

    Set to transmit the second PPDU of the second format to the transmitting STA through the wireless optical communication band based on the information on the second section

    Device.

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