Method for transmitting data in wireless communication system and device therefor

1. An operation method for a station (STA) in a wireless LAN (WLAN) system, the operation method comprising:

receiving a first physical protocol data unit (PPDU); and

transmitting a second PPDU as a response to the first PPDU;

wherein the first or second PPDU includes at least one MAC protocol data unit (MPDU) and a MAC header of the MPDU includes a high-efficiency (HE) control field,

wherein the HE control field is a high throughput (HT) control field in which values of a very high throughput (VHT) subfield indicating a VHT format and an HE subfield indicating an HE format are set to “1”, and includes one or more control subfields,

wherein the one or more control subfields are fixed to preset lengths and included in the HE control field by being aggregated,

wherein the one or more control subfields respectively includes a control content field including control information and a control identifier (ID) field including a type of the control information,

wherein the control ID corresponds to a buffer status response type or an uplink (UL) trigger type,

wherein, based on the control ID field including the control ID corresponding to the buffer status response type, the control content field corresponding to the control ID field includes buffer status response information,

wherein the buffer status response information includes an access category (AC) field and a scaling factor field,

wherein the scaling factor field indicates a common scaling factor for all ACs indicated by the AC field,

wherein the first PPDU and the second PPDU are comprised a physical preamble and a data field sequentially,

wherein the physical preamble includes sequentially a L(legacy)-preamble and a High Efficiency (HE)-preamble,

wherein the HE-preamble includes sequentially an HE-Signal (SIG) A field, an HE-Short Training Field (STF) field, and an HE-Long Training Field (LTF) field,

wherein a first Inverse Discrete Fourier Transform (IDFT)/Discrete Fourier Transform (DFT) period is applied from the L-preamble to the HE-SIG A field and a second IDFT/DFT period is applied from the HE-STF field to the data field, and

wherein the second IDFT/DFT period is 4 times of the first IDFT/DFT period.

2. The operation method according to claim 1 , wherein the control ID further corresponds to an acknowledgement (ACK) or block ACK (BA) request type, an ACK or BA response type, a buffer status response type, a channel state information (CSI) feedback request type, or a CSI feedback response type.

3. The operation method according to claim 2 , wherein, based on the control ID field including the control ID corresponding to the ACK or BA request type, a control content field corresponding to the control ID field includes trigger information about transmission of an ACK or BA response to the ACK or BA request.

4. The operation method according to claim 1 , wherein the buffer status response information further includes a scaling factor field, a queue size field or a transmission opportunity (TXOP) duration field.

5. The operation method according to claim 4 , wherein the AC field includes an AC corresponding to the buffer status response information in the form of a bitmap.

6. The operation method according to claim 2 , wherein, based on the control ID field including the control ID corresponding to the CSI feedback request type, a control content field corresponding to the control ID field includes trigger information about transmission of a CSI feedback in response to the CSI feedback request and feedback request information.

7. The operation method according to claim 6 , wherein the feedback request information includes MRQ sequence identifier (MSI) information, MCS feedback (MFB) information, space-time block coding (STBC) information, coding type information and/or feedback (FB) type information.

8. The operation method according to claim 2 , wherein, based on the control ID field including the control ID corresponding to the CSI feedback response type, a control content field corresponding to the control ID field includes CSI feedback response information.

9. The operation method according to claim 8 , wherein the CSI feedback response information includes unsolicited MFB indication information, MAC feedback sequence identifier (MFSI) information, MFB information, STBC information, coding type information and/or FB type information.

10. The operation method according to claim 1 , wherein, based on the control ID field including the control ID corresponding to the UL trigger type, a control content field corresponding to the control ID field includes trigger information for triggering UL multi-user (MU) transmission.

11. The operation method according to claim 10 , wherein the trigger information includes UL PPDU length information, resource unit allocation information, modulation and coding scheme (MCS) information, coding type information, information on the number of streams, beamforming information, STBC information and/or guard interval (GI) type information.

12. A station (STA) device in a wireless LAN (WLAN) system, comprising:

a radio frequency (RF) unit configured to transmit and receive RF signals; and

a processor configured to control the RF unit,

wherein the STA device is configured to:

receive a first physical protocol data unit (PPDU) and transmit a second PPDU as a response to the first PPDU,

wherein the first or second PPDU includes at least one MAC protocol data unit (MPDU) and a MAC header of the MPDU includes a high-efficiency (HE) control field,

wherein the HE control field is a high throughput (HT) control field in which values of a very high throughput (VHT) subfield indicating a VHT format and an HE subfield indicating an HE format are set to “1” and one or more control subfields,

wherein the one or more control subfields are fixed to preset lengths and included in the HE control field by being aggregated,

wherein the one or more control subfields respectively includes a control content field including control information and a control identifier (ID) field including a type of the control information,

wherein the control ID corresponds to a buffer status response type or an uplink (UL) trigger type,

wherein, based on the control ID field including the control ID corresponding to the buffer status response type, the control content field corresponding to the control ID field includes buffer status response information,

wherein the buffer status response information includes an access category (AC) field and a scaling factor field,

wherein the scaling factor field indicates a common scaling factor for all ACs indicated by the AC field,

wherein the first PPDU and the second PPDU are comprised a physical preamble and a data field sequentially,

wherein the physical preamble includes sequentially a L(legacy)-preamble and a High Efficiency (HE)-preamble,

wherein the HE-preamble includes sequentially an HE-Signal (SIG) A field, an HE-Short Training Field (STF) field, and an HE-Long Training Field (LTF) field,

wherein a first Inverse Discrete Fourier Transform (IDFT)/Discrete Fourier Transform (DFT) period is applied from the L-preamble to the HE-SIG A field and a second IDFT/DFT period is applied from the HE-STF field to the data field, and

wherein the second IDFT/DFT period is 4 times of the first IDFT/DFT period.