Data transmission method in wireless communication system and device therefor

An uplink (UL) multi-user (MU) transmission method of an STA in a wireless communication system, the method comprising:

• receiving a DL physical protocol data unit (PPDU), the DL PPDU comprising resource allocation information for an UL MU transmission of a station (STA);
• and
• sending an UL MU PPDU generated based on the DL PPDU,
• wherein the UL MU PPDU comprises a first part having a first inverse discrete Fourier transform (IDFT)/discrete Fourier transform (DFT) period and a second part having a second IDFT/DFT period which is four times the first IDFT/DFT period,
• wherein the first part is transmitted through at least one 20 MHz channel of a location corresponding to a frequency resource indicated by the resource allocation information, and
• wherein the second part is transmitted using the frequency resource indicated by the resource allocation information.

A station (STA) device of a wireless LAN (WLAN) system, comprising:

• an RF unit configured to send or receive a radio signal;
• and
• a processor configured to control the RF unit,
• wherein the processor is further configured to receive a DL physical protocol data unit (PPDU), the DL PPDU comprising resource allocation information for an uplink (UL) multi-user (MU) transmission of the STA, and send an UL MU PPDU generated based on the DL PPDU,
• wherein the UL MU PPDU comprises a first part having a first inverse discrete Fourier transform (IDFT)/discrete Fourier transform (DFT) period and a second part having a second IDFT/DFT period which is four times the first IDFT/DFT period,
• wherein the first part is received through at least one 20 MHz channel of a location corresponding to a frequency resource indicated by the resource allocation information, and
• wherein the second part is received using the frequency resource indicated by the resource allocation information.