A method is provided for transmitting data performed by a station (STA) device in a Wireless Local Area Network (WLAN) system. The STA device generates a Physical Protocol Data Unit (PPDU) including a physical preamble and a data field sequentially, and transmits the PPDU. The physical preamble includes sequentially a Legacy (L)-preamble and a High Efficiency (HE)-preamble. The HE-preamble includes sequentially an HE-Signal (SIG) A field, an HE-SIG B field, an HE-Short Training Field (STF) field, and an HE-Long Training Field (LTF) field, A first Inverse Discrete Fourier Transform (IDFT)/Discrete Fourier Transform (DFT) period is applied from the L-preamble to the HE-SIG B field and a second IDFT/DFT period is applied from the HE-STF field to the data field. The second IDFT/DFT period is 4 times of the first IDFT/DFT period. The HE SIG A field includes common control information and the HE-SIG B field includes user-specific information.