Wireless communication terminal and wireless communication method for multi-user uplink transmission

A wireless station (STA), the STA comprising:

• a transceiver;
• and
• a processor,
• wherein the processor is configured to:
• receive, through the transceiver, a trigger frame from access point (AP),
• wherein the trigger frame includes an AID (association identifier) field for setting a temporary AID of one or more STAs including the STA,
• wherein the one or more STAs are not associated with the AP, and
• wherein the temporary AID is used for a random access procedure of the one or more STAs not associated with the AP, and indicates at least one resource unit for the random access procedure of each of the one or more STAs,
• transmit an uplink data for the random access procedure to the AP through the at least one resource unit, and
• receive a ACK (acknowledgment) frame in response to the uplink data from the AP,
• wherein the Ack frame includes Ack information for some or all of the one or more STAs,
• wherein the Ack information is identified from the Ack frame based on the temporary AID,
• wherein an OFDMA backoff (OBO) counter is used for uplink orthogonal frequency division multiple access (UL-OFDMA) based random access,
• wherein the OBO counter is decremented based on the number of resource units indicated by the temporary AID, and
• wherein the one or more STAs, whose OBO counter is smaller than or equal to the number of resource units, perform the random access procedure.