Method and device for transmitting and receiving traffic stream in wireless lan system

A wireless device for transmitting and receiving a traffic stream in a wireless local area network (WLAN) system, the wireless device comprising:

• a radio frequency (RF) unit to transmit and receive a radio signal;
• and
• a processor operatively connected to the RF unit,
• wherein the processor broadcasts a beacon frame comprising allocation information on a contention-free period (CFP) and allocation information on a contention period (CP) to a station (STA) and transmits a downlink traffic stream to the STA or receiving an uplink traffic stream from the STA, based on the allocation information on the CFP, and
• the allocation information on the CFP indicates that the downlink traffic stream is transmitted without performing a clear channel assessment (CCA) during the CFP and indicates that the uplink traffic stream is received with performing a CCA during the CFP.