Data transmission method in wireless communication system and device therefor

A Station (STA) device in a wireless local area network (WLAN) system, the STA device comprising:

• a transceiver configured to transmit and receive a wireless signal;
• and
• a processor configured to control the transceiver,
• wherein the processor is further configured to:
• generate a downlink (DL) multi-user (MU) physical protocol data unit (PPDU) including a physical preamble and a data field and transmits the DL MU PPDU,
• wherein the data field includes at least one medium access control (MAC) protocol data unit (MPDU), the at least one MPDU includes a MAC header and a MAC frame body,
• wherein the MAC header includes acknowledge (ACK) indication information,
• wherein the ACK indication information includes frequency resource allocation information for an uplink (UL) MU orthogonal frequency division multiple access (OFDMA) transmission of ACK frames and modulation and coding scheme (MCS) level information, and
• wherein the frequency resource allocation information includes an index value indicating a resource unit allocated for the UL MU OFDMA transmission of the ACK frames, and the resource unit corresponds to a 26-tone resource unit, a 52-tone resource unit, a 106-tone resource unit, a 242-tone resource unit, a 484-tone resource unit, or a 996-tone resource unit,
• transmits the DL MU PPDU to a plurality of recipient STAs, and
• receive the ACK frames from the plurality of recipient STAs simultaneously as a response to the DL MU PPDU.