Data transmission method and device in wireless communication system

A station, STA, device in a wireless local area network, WLAN, system, the STA device comprising:

• a radio frequency, RF unit, transmitting and receiving a radio signal;
• and
• a processor controlling the RF unit,
• wherein the STA device is configured to receive an uplink, UL, frame from a first STA, to send a trigger frame for the uplink data frame, and to receives a UL multiuser, MU, frame,
• wherein the uplink data frame comprises first transmit, Tx, operating mode information indicating a Tx operating mode to be changed.
• wherein the trigger frame for the UL MU transmission, the trigger frame indicating resource allocation for the UL MU transmission based on the received Tx operating mode information, and
• wherein the first Tx operating mode information comprises Tx spatial stream number information and Tx channel bandwidth information.