Method and apparatus for transmitting PPDU on basis of S-TDMA in wireless LAN system

A wireless device being an access point (AP) for transmitting/receiving a Physical layer Protocol Data Unit (PPDU) based on Scheduled-Time Division Multiple Access (S-TDMA) in a wireless LAN system, the wireless device comprising:

• a memory;
• a transceiver;
• and a processor being operatively coupled with the memory and the transceiver, wherein the processor:
• transmits a trigger frame to a first station (STA) and a second STA, and receives a first trigger-based frame from the first STA and receives a second trigger-based frame from the second STA, wherein the trigger frame includes a common information field and a user information field, wherein the common information field includes S-TDMA indication information on that the S-TDMA can be performed, wherein the user information field includes allocation information for a first resource unit (RU) to which the first trigger-based frame and the second trigger-based frame are to be transmitted, a first symbol offset information for the first trigger-based frame, and a second symbol offset information for the second trigger-based frame, wherein the first trigger-based frame is transmitted in the first RU based on the first symbol offset information, wherein the second trigger-based frame is transmitted in the first RU based on the second symbol offset information, wherein a guard time exists between the first trigger-based frame and the second trigger-based frame, wherein the guard time is configured as an SIFS, wherein, in case the guard time is shorter than a CS duration performing channel sensing (CS), if a channel is Busy during the CS duration, the second trigger-based frame is transmitted, and if the channel is Idle during the CS duration, the second trigger-based frame is not transmitted.

A method for receiving a Physical layer Protocol Data Unit (PPDU) based on Scheduled-Time Division Multiple Access (S-TDMA) in a wireless LAN system, the method comprising:

• receiving, by a first station (STA), a trigger frame to an access point (AP);
• and transmitting, by the first STA, a first trigger-based frame based on the trigger frame, wherein the trigger frame includes a common information field and a user information field, wherein the common information field includes S-TDMA indication information on that the S-TDMA can be performed, wherein the user information field includes allocation information for a first resource unit (RU) to which the first trigger-based frame and the second trigger-based frame are to be transmitted, a first symbol offset information for the first trigger-based frame, and a second symbol offset information for the second trigger-based frame, wherein the first trigger-based frame is transmitted in the first RU based on the first symbol offset information, wherein the second trigger-based frame is transmitted in the first RU based on the second symbol offset information, wherein a guard time exists between the first trigger-based frame and the second trigger-based frame, wherein the guard time is configured as an SIFS, wherein, in case the guard time is shorter than a CS duration performing channel sensing (CS), if a channel is Busy during the CS duration, the second trigger-based frame is transmitted, and if the channel is Idle during the CS duration, the second trigger-based frame is not transmitted.