Method for transmitting uplink frame in wireless local area network and wireless device using the same

A wireless terminal using a method for transmitting an uplink frame in a wireless local area network (WLAN), the wireless terminal comprising:

• a transceiver for transmitting and receiving a radio signal;
• and
• a processor operatively coupled to the transceiver, wherein the processor is configured for:
• receiving from an access point (AP) a trigger frame including association identifier information for orthogonal frequency division multiple access (OFDMA)-based random access and resource allocation information indicating a resource unit corresponding to the association identifier information, wherein the association identifier information indicates any one of a first value for a first STA group associated with the AP and a second value for a second STA group un-associated with the AP;
• and
• performing a countdown operation according to the association identifier information based on a backoff value which is set in a backoff counter for the OFDMA-based random access in order to transmit the uplink frame.