WO2016088958A1

WO2016088958A1 - Method for transmitting fdr in wireless lan system and device therefor

Info

Publication number: WO2016088958A1
Application number: PCT/KR2015/005937
Authority: WO
Inventors: 김서욱; 윤지훈; 김정기; 조한규
Original assignee: 엘지전자 주식회사; 서울과학기술대학교 산학협력단
Priority date: 2014-12-04
Filing date: 2015-06-12
Publication date: 2016-06-09
Also published as: KR101931949B1; KR20170080601A

Abstract

The present document relates to a method for transmitting an FDR in a wireless LAN system and a device therefor. In a wireless LAN system, a station (STA) is configured so as to simultaneously transmit data through a different subband within a channel through which an AP transmits data, wherein, on the basis of the header information of the data transmitted by the AP, the use or non-use of a subband separated by as much as a predetermined guardband from the subband used by the AP for transmitting the data may be determined.

Description

【Specification】

[Name of invention]

FDR transmission technique in wireless LAN system and apparatus therefor

Technical Field

The following description relates to a FOR transmission scheme and a device therefor in a wireless communication system, in particular, a WLAN system.

Background Art

Although the channel for downlink proposed below may be applied to various wireless communications, hereinafter, a wireless local area network (WLAN) system will be described as an example of a system to which the present invention can be applied.

Recently, with the development of information and communication technology, various wireless communication technologies are being developed. Wireless LAN (WLAN) is based on the radio frequency technology, using a portable terminal device such as a personal digital assistant (PDA), a laptop computer, a portable multimedia player (PMP), etc. It is a technology that allows access to the Internet wirelessly at home, at work, or in specific service areas.

[004] A standard for WLAN technology is being developed as an IEEE (Inst IT of Electrical and Electronics Engineers) 802.11 standard. IEEE 802.11a and b are described in 2.4. Using unlicensed band at GHz or 5 GHz, IEEE 802.11b provides a transmission rate of 11 Mbps, and IEEE 802.11a provides a transmission rate of 54 Mbps. IEEE 802.11g uses Orthogonal frequency-division mult multiplexing (OFDM) at 2.4 GHz, 54 It provides a transmission rate of Mbps. IEEE 802. 11η applies multi-input multiple-multiple output OFDM (MIDM-OFDM) to provide a transmission rate of 300 Mbps for four spatial streams. IEEE 802.11η supports channel bandwidths up to 40 MHz, in this case 600 Mbps.

The wireless LAN standard described above uses up to 160MHz bandwidth, supports eight spatial streams, and goes through the IEEE 802.11ac standard supporting speeds of up to lGbi t / s. It is done. [Detailed Description of the Invention]

[Technical problem]

FDR (Ful l Duplex Radio) technology, which is currently being actively developed, has the advantage of simultaneous transmission and reception, and thus can be expected to improve performance when applied to multiple communication systems. In the following description of the present invention, FDR is applied to an IEEE 802.11 system. However, since the IEEE 802.11 system operates on multiple channels based on CSMA-CA, there is a technical problem to be careful when applying FDR, and the present invention intends to solve this problem.

Technical Solution

In one aspect of the present invention for solving the above problems, in a method for transmitting data to a first AKAccess Point by a first station (STA) in a WLAN system, a first in one radio channel The AP determines that the specific AP is transmitting the first data to the specific STA through the subband, The second STA transmits the second data to the AP 1 1 through the second subband in the one wireless channel during the first data transmission, and the first STA transmits the second data according to the preamble information of the first data. The present invention proposes a data transmission method for determining whether to select a subband as a subband separated from the first subband by a predetermined guard band.

In another aspect of the present invention, in a method in which a first AKAccess Point) transmits data to a first station (STA) in a WLAN system, a specific STA is identified through a first subband in one radio channel. Confirming that the first data is being transmitted to the AP, and transmitting the second data to the first STA through a second subband in the one wireless channel during the first data transmission of the specific STA, wherein the first data According to the preamble information, the first AP proposes a data transmission method for determining whether to select the second subband as a subband separated from the first subband by a predetermined guard band.

In another aspect of the present invention, in a first station (STA) apparatus for transmitting data to a first access point (AP) in a wireless LAN system, signal transmission and reception are possible simultaneously through one wireless channel. A transceiver configured to be; And a processor connected to the transceiver to control an operation of the transceiver, wherein the processor determines that a specific AP is transmitting first data to a specific STA through a first subband in the one radio channel; Allow the transceiver to transmit second data to the first AP via a second subband in the one wireless channel of the first data transmission of the specific AP. The processor may determine whether to select the second subband as a subband spaced apart from the first subband by a predetermined guard band according to the preamble information of the first data. Suggest.

In addition, in another aspect of the present invention, in a first AP device for transmitting data to a first station (STA) in a WLAN system, signal transmission and reception are possible at the same time through one wireless channel. A transceiver configured to be; And a processor connected to the transceiver to control an operation of the transceiver, wherein the processor determines that a specific STA transmits first data to a specific AP through a first subband in the one radio channel. Through a second subband in the one radio channel of the first data transmission of the specific STA

And control the transceiver to transmit the second data to the first STA, wherein the processor is configured to assign the second subband to the first subband and a predetermined guard band according to the preamble information of the first data. We propose an AP device that decides whether to select a subband separated by a band).

Advantageous Effects

[0011]. According to the present invention as described above, by applying the FDR in the data transmission in the WLAN system, not only can the transmission efficiency be increased, but also the in-device / period interference caused by the FDR can be efficiently solved.

[Brief Description of Drawings]

1 is a view showing an example of the configuration of a wireless LAN system. 2 is a view showing another example of the configuration of a wireless LAN system.

3 is a view for explaining the DCF mechanism in the WLAN system.

4 and 5 are exemplary diagrams for explaining the problem of the existing masonry solving mechanism.

FIG. 6 is a diagram for describing a mechanism for solving a hidden node problem using an RTS / CTS frame.

FIG. 7 is a diagram for explaining a mechanism for solving an exposed node problem using an RTS / CTS frame.

FIG. 8 is a diagram for describing in detail a method of operating using the RTS / CTS frame as described above.

9 shows a conceptual diagram of a terminal and a base station supporting FDR in a wireless communication system.

FIG. 10 shows a conceptual diagram for IDI occurring when a base station uses a FO mode (simultaneous transmission / reception mode using the same frequency) in the same resource.

11 is a view for explaining a wireless LAN environment to which an embodiment of the present invention can be applied.

12 and 13 are diagrams for explaining a method for the terminal to transmit data to the AP according to an embodiment of the present invention.

FIG. 14 illustrates a method in which a terminal transmits data to an AP without using a guard band in the situation as shown in FIG. 13.

15 is a view for explaining an apparatus for performing data transmission by applying the FDR as described above. [Form for implementation of invention]

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. The detailed description, which will be given below with reference to the accompanying drawings, is intended to describe exemplary embodiments of the present invention, rather than to represent the only embodiments in which the invention may be practiced.

The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details. In some cases, well-known structures and devices are omitted or are shown in blotting degree around the key functions of each structure and device in order to avoid obscuring the concepts of the present invention.

In addition, in the following description, a "terminal" is a concept of any user equipment performing a communication function, including a STA in a WLAN system and a UE in an LTE-A system.

As described above, the following description relates to an FDR transmission technique and an apparatus therefor in a WLAN system. To this end, first, a WLAN system to which the present invention is applied will be described in detail.

1 is a view showing an example of the configuration of a wireless LAN system.

As shown in Figure 1, the WLAN system includes one or more basic service set (Bas i Service Set, BSS). A BSS is a set of stations (STAs) that can successfully synchronize and communicate with each other.

[0031] STA is a medium access control (Medium Access Control, MAC) for the wireless medium A logical entity including a physical layer interface, which includes an access point (AP) and a non-AP Stat ion (AP STA). The portable terminal operated by the user among the STAs is a non-AP STA, and when referred to simply as an STA, it may also refer to a non-AP STA. Non-AP STA is a terminal, a wireless transmit / receive unit (WTRU), a user equipment (User)

It may also be called other names such as Equipment (UE), Mobile Station (MS), Mobile Terminal, or Mobile Subscriber Unit.

And, the AP is an entity that provides access to the Distribution System (Distribution System, DS) through the wireless medium to the ^ 350 60 ¾∑ coupled to it. The AP may be called a centralized controller, a base station (BS), a Node-B, a base transceiver system (BTS), or a site controller.

BSS can be divided into an infrastructure (SS) BSS and (Independent) BSS (IBSS).

BBS shown in FIG. 1 is IBSS. IBSS means BSS that does not include AP, and because it does not include AP, it does not allow access to DS and forms a self-contained network.

2 is a view showing another example of the configuration of a wireless LAN system.

The BSS shown in FIG. 2 is an infrastructure BSS. Infrastructure BSS includes one or more STAs and APs. In the infrastructure BSS, communication between non-APSTAs is performed via an AP. However, when a direct link is established between non-AP STAs, direct communication between non-AP STAs is also possible. As shown in FIG. 2, a plurality of infrastructure BSSs may be interconnected through a DS. A plurality of BSSs connected through a DS is called an extended service set (ESS). STAs included in the ESS may communicate with each other, and a non-APSTA may move from one BSS to another BSS while communicating seamlessly within the same ESS.

DS is a mechanism (mechanism) for connecting a plurality of APs, it does not necessarily need to be a network, there is no restriction on the form if it can provide a predetermined distribution service. For example, the DS may be a wireless network such as a mesh network or a physical structure that connects APs to each other.

On the basis of the above it will be described a collision detection technology in a WLAN system.

As described above, since various factors affect the channel in the wireless environment, there is a problem in that the transmitting end cannot accurately perform floor detection. Therefore, 802.11 introduced the distributed coordination function (DCF), a carrier sense multiple access / collision avoidance (CSMA / CA) mechanism.

3 is a view for explaining the DCF mechanism in the WLAN system.

The DCF performs a clear channel assessment (CCA) that senses a medium for a specific period (eg, DIFS: DCF inter-frame space) before STAs having data to transmit transmit data. At this time, if the medium is idle, the STA can transmit a signal using the medium. However, if the medium is busy, it is assumed that several STAs are already waiting to use the medium. In addition, data can be transmitted after waiting a further random backoff period (random backof f per iod). In this case, the random backoff period makes it possible to avoid the stratification. Assuming that there are several STAs for transmitting data, each STA has a probability of different backoff intervals, which is different from each other. This is because it has a transmission time. When one STA starts transmission, the other STAs cannot use the medium.

Briefly, the random backoff time and procedure are as follows.

When a certain medium is changed from busy to idle, several STAs start preparing to send data. At this time, STAs that want to transmit data in order to minimize floor stones each select a random backoff count and wait for the slot time. The random backoff count is a pseudo-random integer value and selects one of the uniformly distributed values in the range of [0 CW]. CW means 'content ion window'.

CW parameter takes the CWmin value as the initial value, but if the transmission fails, the value is doubled. For example, if an ACK response for a transmitted data frame is not received, it can be regarded as a stagnation. If CT value has CWmax value, it maintains CWmax value until data transmission succeeds, and data transmission succeeds and resets to CWmin value. At this time, CW, CWmin, CWmax is preferably to maintain 2 "-1 for convenience of implementation and operation.

Meanwhile, when the random backoff procedure starts, the STA selects the random backoff count within the range of [0 CW] and continuously monitors the medium while the backoff slot is counted down. In the meantime, if the medium is busy, When it stops and the medium is idle again, it resumes counting down the remaining backoff slots.

Referring to FIG. 3, when there are data that STAs want to send, STA3 immediately transmits a data frame because the medium is idle as much as DIFS, and the remaining STAs wait for the medium to be idle. Since the medium has been busy for some time, several STAs will see an opportunity to use the medium. Thus, each STA selects a random backoff count. In FIG. 3, STA 2, which has selected the smallest backoff count, transmits a data frame.

After the transmission of STA2 is finished, the medium again becomes idle, and the STAs resume counting down for the backoff interval that was stopped again. FIG. 3 illustrates that STA 5, which has the next smallest random backoff count value after STA 2 and stops counting down when the medium is busy, starts data frame transmission after counting down the remaining backoff slots. Overlap with the backoff count value shows that a stratification has occurred. In this case, since both STAs do not receive the ACK answer after the data transmission, the CW is doubled and the random backoff count value is selected again.

As already mentioned, the most basic of CSMA / CA is carrier sensing. The terminal may use physical carrier sensing and virtual carrier sensing to determine whether the DCF medium is busy or idle. Physical carrier sensing is performed at the PHY (physicaI layer) stage, and is used for energy detect ion or preamble detection. detection is done. For example, if the voltage level at the receiver is measured or if the preamble is determined to be read, it can be determined that the medium is busy. Virtual carrier sensing is performed by setting a NAVC network allocation vector to prevent other STAs from transmitting data through a value of a duration field of a MAC header. In order to reduce the possibility of masonry, a robust collision detection mechanism was introduced, which can be seen in the following two examples. For convenience, it is assumed that the carrier sensing range is the same as the transmission range.

Specifically, FIG. 4 is a diagram for explaining hidden node issues. In this example, STA A and STA B are in communication, and STA C has information to transmit. Specifically, when STAA is transmitting information to STAB, when STAC carrier senses the medium before sending data to STAB, STA C is out of STA A's transmission range, so STA A cannot detect signal transmission and the medium is idle. There is a possibility that it is in a state As a result, STA B receives the information of STA A and STA C at the same time, a collision occurs. At this time, STA A may be referred to as a hidden node (hidden node) of STA C.

Meanwhile, FIG. 5 is a diagram for explaining exposed node issues. Currently, the STAB is transmitting data to STAA. At this time, the STAC performs carrier sensing. Since the STA B is transmitting information, the STAC detects that the medium is busy. As a result, whether STA C would like to send data to STA D Even if the medium is sensed as busy, there is a situation that the user needs to wait unnecessarily until the medium becomes idl e. That is, STA A may prevent transmission of information of STA C even though it is outside the CS range of STA C. At this time, STA C becomes an exposed node of STA B.

In the above-mentioned situation, the neighboring STAs transmit information of two STAs by introducing a short s ignaling packet such as a request to send (RTS) and a c lear to send (CTS) in order to use the layer avoidance mechanism well. It can leave room for overhearing or not. That is, when the STA to transmit the data transmits the RTS frame to the STA receiving the data, the receiving STA may transmit the CTS frame to the neighboring UEs to inform that it will receive the data.

In FIG. 6, STA A and STA C are both trying to transmit data to STA B. FIG. When STA A sends the RTS to STA B, STA B transmits the CTS to both STA A and STA C around it. As a result, STA C waits until the data transmission of STA A and STA B is completed, thereby avoiding the dolmens.

7 is a view for explaining a mechanism for solving the node problem exposed using the RTS / CTS frame.

By overhearing the RTS / CTS transmission of the STA A and the STA B in FIG. 7, the STA C may know that the stratification does not occur even when transmitting data to another STA D. That is, STA B transmits the RTS to all the surrounding terminals, and only STA A having the data to actually transmit the CTS. STA C receives RTS only and CTS of STA A STA A can see that it is outside the CS range of STC C because it did not receive.

In FIG. 8, the transmitting STA may transmit an RTS frame to the receiving STA that may transmit a signal after DIFF (Di str ibuted IFS). The receiving STA receiving the RTS frame may transmit the CTS to the transmitting STA after SIFS (Short IFS). The transmitting STA receiving the CTS from the receiving STA may transmit data as shown in FIG. 8 after SIFS. The receiver STA receiving the data may transmit an ACK response to the data received after SIFS.

Meanwhile, the STA that has received the RTS / CTS of the transmitting STA among the neighboring STAs other than the above-mentioned transmitting and receiving STAs is busy of the medium through the reception of the RTS / CTS as described above with reference to FIGS. 6 and 7. It may determine whether or not, and accordingly can set a network al locat ion vector (NAV). When the NAV period ends, a process for solving the stratification as described above with reference to FIG. 3 may be performed after DIFS.

Ful duplex radio (FDR) means a system that wants to send and receive at the same time using the same resources in the transmission device. In this case, the same resource may mean the same frequency at the same time.

9 shows a conceptual diagram of a terminal and a base station supporting FDR in a wireless communication system. The system shown in Figure 9 is an LTE or LTE-A based macro base station (eNB) and small base stations (Femto, Pico / Micro) base stations are assumed.

In this situation, there are two types of interference due to the support of FDR.

[0064] Intra-device interference

Means that a signal transmitted from a transmitting antenna in one base station or a terminal is received by the receiving antenna to act as interference.

[0066] Indirect inter-device interference

The base station black means that the uplink signal transmitted from the terminal or the like is received by the adjacent base station or the terminal to act as interference.

Inter-device interference (hereinafter referred to as IDI) is interference occurring only in the FDR due to using the same resource in the cell (cel l).

10 shows a conceptual diagram for an IDI generated when a base station uses an FD mode (simultaneous transmission / reception mode using the same frequency) in the same resource.

10 is a simple example showing two UE JE1 and UE2) for easy IDI description, and the present invention does not limit the number of UEs.

[0071] In a communication system using a conventional Ful-duplex, IDI is not generated by using frequency division duplex (FDD) or time division duplex (TDD), that is, different transmission / reception resources. Interference of neighbor cells on the existing communication system is still valid in the FDR system, but the description thereof is omitted.

When the FDR is applied to the IEEE 802.11 system, the biggest problem may be interference between the DL and UL. Traditionally, only one UL or DL at a time in a network However, when FDR is applied, simultaneous DL and UL exist. At this time, interference occurs when the channels used by the DL and the UL are adjacent to each other. One embodiment of the present invention to be described below is intended to solve this.

As described above, the present invention relates to a terminal / STA that supports FDR, but the application of FDR does not assume that signals are simultaneously transmitted and received through subbands in the same channel. That is, although UL and DL communication can be performed simultaneously in one channel, it is assumed that UL and DL communicate through different subbands.

For example, it is assumed that a subband in which the AP of FIG. 11 transmits data to an STA supporting FDR and a subband in which the STA supporting FDR transmits data to the AP are different.

On the other hand, it is assumed that the AP according to the present embodiment supports not only the terminal / STA supporting the FDR but also the terminal / STA not supporting the conventional FDR, as shown in FIG.

12 and 13 are diagrams for explaining a method for a terminal to transmit data to an AP according to an embodiment of the present invention.

In the description of FIGS. 12-13 and the following embodiments, the "subband" may be a 20 MHz channel in 802.11, or may be a resource unit smaller than a 20 MHz channel when 0FDMA is applied. have. The part marked "AP->STA" indicates the DL PPDU that the AP is transmitting, including PLCP preamble and header Can be configured. The portion marked "STA->AP" indicates the PPDU being transmitted by the STA.

First, the AP may start transmitting on a specific subband. The PLCP header of the PPDU transmitted by the AP may include the address or BSS color information of the AP currently being transmitted. Through this information, UEs can know that their AP is currently transmitting data.

BSS color information transmitted through the PLCP header is specified in the IEEE 802.11ah standard as information for controlling the reception operation by distinguishing the BSS for transmitting data by the receiving terminal.

At this time, if the terminal also has a frame to transmit to the AP, it can transmit data using the empty subband. However, since its AP is currently transmitting data, it is proposed to transmit with a constant guard band (or guard subband) because UL / DL interference occurs between adjacent channels when transmitting in the immediate subband.

On the other hand, when the AP currently transmitting data through the information of the PLCP header is not its AP, the terminal may transmit as shown in FIG. 13 without having a guard band. This is because the AP does not need to consider UL / DL interference between adjacent channels since it is not transmitting.

[0083] The following information may be added to the PLCP header information described in the embodiment of the present invention as described above.

Whether to use the guardband: the terminal may inform whether or not to use the guard band when transmitting to the FDR in the remaining subband. If the decoding performance of the AP In good cases, you may not need a guardband.

Guardband size: when the terminal needs to transmit the guardband to adjust the size. This may depend on the performance of the AP and the subband size of the PPDU being transmitted.

As described above, the terminal / STA may determine whether to apply the guard band in the FDR operation through the information of the PLCP header. To this end, as shown in FIG. 12 and FIG. 13, it is preferable that the terminal / STA does not start data transmission to the AP until the reception / decoding of PLCP header information of the PPDU of the AP is completed. After completing the reception of the PLCP header information, the terminal / STA may initiate data transmission to the AP through a contention step in the corresponding subband as indicated by "backof f".

In the case of not using the guard band as shown in Figure 14, because the DL / UL interference between adjacent channels there is a more robust MCS (ie, lower MCS) when the UE transmits data to the AP It is preferable to use. Alternatively, to transmit data without guard band, it is possible to lower the data transmission power.

In summary, when the transmission power when the guard band is not used, PI, MCS level is called MCS 1, and the transmission power when using the gait band is P2, MCS level is MCS 2, (1) PI <P2, or

(2) MCS 1 <MCS2

It is desirable to satisfy.

And before the UE transmits the data frame to the AP transmits the RTS framing first and then the AP responds to the CTS is also possible to determine the appropriate MCS after measuring the interference by the RTS. In addition, the size of the guard band can also be known through the CTS.

12 to 14 described above describe only the situation of performing UL transmission during DL transmission, but vice versa. That is, while a specific STA is transmitting data to a specific AP, the AP may determine whether to use a guard band based on header information of data transmitted by the STA.

15 is a diagram for explaining an apparatus for performing data transmission by applying the FDR as described above.

The wireless device 800 of FIG. 15 may correspond to a particular STA ᅳ of the above description and the wireless device 850 may correspond to the AP of the above description.

The STA may include a processor 810, a memory 820, a transceiver 830, and the AP 850 may include a processor 860, a memory 870, and a transceiver 880. have. The transceivers 830 and 880 may transmit / receive radio signals and may be executed in a physical layer such as IEEE 802.11 / 3GPP. The processors 810 and 860 are executed at the physical layer and / or MAC layer, and are connected to the transceivers 830 and 880. Processors 810 and 860 may perform the interference control procedure mentioned above. [0098] Processors 810 and 860 and / or transceivers 830 and 880 may include a specific integrated circuit (appl icat ion—spec i c ic integrated ci rcui t, ASIC), other chipset, logic circuit and / or data processor. It may include. The memory 820 and 870 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage unit. When an embodiment is executed by software, the method described above can be executed as a module (eg, a process, a function) that performs the functions described above. The modules may be stored in memory 820, 870 and executed by processor 810, 860. The memories 820 and 870 may be disposed inside or outside the processes 810 and 860 and may be connected to the processes 810 and 860 by well-known means.

Detailed description of the preferred embodiment of the present invention disclosed as described above is provided to enable those skilled in the art to implement and practice the present invention. Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will understand that the present invention can be variously modified and changed from the above description. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Industrial Applicability

The present invention as described above has been described assuming that it is applied to the IEEE 802.11-based wireless LAN system, but is not limited thereto. Invention wireless The same applies to various wireless systems that require interference control between devices.

Claims

[Claim]

[Claim 1]

In a method for transmitting data to a first A (Access Point) by a first station (STA) in a wireless LAN system,

Determine that a specific AP is transmitting first data to a specific STA through a first subband in one radio channel,

Transmitting second data to the first AP through a second subband in the one wireless channel of the first data transmission of the specific AP,

And according to the preamble information of the first data, the first STA determines whether to select the second subband as a subband spaced apart from the first subband by a predetermined guard band.

[Claim 2]

The method of claim 1,

When the preamble information of the first data indicates that the specific AP is the first AP, the first STA selects the second subband as a subband spaced apart from the first subband by a predetermined guard band. Transmission method.

[Claim 3]

The method of claim 1,

When the preamble information of the first data indicates that the specific AP is a second AP instead of the first AP, the first STA selects the second subband as a subband adjacent to the first subband. Data transfer method.

[Claim 4]

9Λ The method of claim 1,

And when the preamble information of the first data indicates that the predetermined guard band is not necessary, the first STA selects the second subband as a subband adjacent to the first subband.

[Claim 5]

The method of claim 1,

When the first STA selects the second subband as a subband adjacent to the first subband, the first transmission power and the first MCS (Modulat ion and Coding Scheme) level for the second data transmission are

When the first STA selects the second subband as a subband separated from the first subband by a predetermined guard band, compared with a second transmit power and a second MCS level for the second data transmission,

(1) first transmit power <second transmit power, or

(2) First MCS Level <Second MCS Level

To satisfy the data transmission method.

[Claim 6]

The method of claim 1,

The preamble information of the first data includes information on whether the predetermined guardband is used and information on the size of the predetermined guardband.

[Claim 7]

According to claim 1,

The transmission of the second data to the first AP is the first of the specific AP. A data transmission method performed during data transmission and started after receiving preamble information of the first data.

[Claim 8]

In paragraph 1

The first data is a PLCP (Physical Layer Convergence Procedure) preamble, PPDlKPLCP Protocol Data Unit (MPD) including header ψ MPDU (MAP Protocol).

[Claim 9]

In a method for transmitting data to a first station (STA) by a first A Access Point in a WLAN system,

Through a first subband in one radio channel, a specific STA confirms that the first data is transmitted to a specific AP.

Transmitting second data to the first STA through a second subband in the one wireless channel of the first data transmission of the specific STA,

The first AP determines whether to select the second subband as a subband spaced from the first subband by a guard band according to the preamble information of the first data.

[Claim 10]

In a first station (STA) apparatus for transmitting data to a first A Access Point in a WLAN system,

A transceiver configured to simultaneously transmit and receive signals through one wireless channel; And A processor connected to the transceiver to control an operation of the transceiver;

When the processor determines that a specific AP is transmitting first data to a specific STA through a first subband in the one radio channel, a second in the one radio channel of the first data transmission of the specific AP Control the transceiver to transmit second data to the first AP via a subband,

And the processor determines whether to select the second subband as a subband apart from the first subband by a predetermined guard band according to the preamble information of the first data.

[Claim 11]

In a first AP device for transmitting data to a first station (STA) in a WLAN system

A transceiver configured to be capable of transmitting and receiving signals simultaneously through one wireless channel; And

A processor connected to the transceiver to control an operation of the transceiver;

When the processor determines that a specific STA is transmitting first data to a specific AP through a first subband in the one radio channel, a second in the one radio channel of the first data transmission of the specific STA Control the transceiver to transmit the second data to the first STA through a subband,

The processor is configured to separate the second subband from the first subband by a predetermined guard band according to the preamble information of the first data. An AP device that determines whether to select as a subband