Method for transmitting uplink frame in wireless LAN system, and wireless terminal using same

1. A method for transmitting an uplink frame in a wireless LAN system, comprising:

after a first trigger frame for uplink transmission of multi-users is received from an access point (AP), configuring, by a user station (STA), a backoff counter for a contention-based channel access based on first parameter information for the multi-users;

performing, by the user STA, a countdown operation based on the backoff counter configured based on the first parameter information;

after a second trigger frame is received, suspending, by the user STA, the countdown operation to transmit a trigger-based uplink frame as a response to the second trigger frame; and

if an acknowledgement (ACK) frame for the trigger-based uplink frame is not received, resuming, by the user STA, the suspended countdown operation.

2. The method of claim 1 , further comprising:

performing, by the user STA, the countdown operation based on the backoff counter configured based on second parameter information for a single user, until the first trigger frame is received after a reception of a beacon frame being periodically transmitted from the AP.

3. The method of claim 2 , further comprising:

after the first trigger frame is received, initiating, by the user STA, a timer operation based on timer information related to a valid interval that the first parameter information is validly to be used.

4. The method of claim 3 , wherein the first parameter information, the second parameter information, and the timer information are included in the beacon frame.

5. The method of claim 4 , wherein the first parameter information includes a first arbitration interframe space (AIFS) value set for the multi-users, a first contention window (CW) minimum value set, and a first CW maximum value set, and

wherein the second parameter information includes a second AIFS value set for operations of a Quality of Service (QoS) facility, a second CW minimum value set, and a second CW maximum value set.

6. The method of claim 5 , wherein the first AIFS value set includes a first value used for a first access category of the access category background (AC_BK) type, a second value used for a second access category of the access category best effort (AC_BE) type, a third value used for a third access category of the access category video (AC_VI) type, and a fourth value used for a fourth access category of the access category voice (AC_VO) type,

wherein the first CW minimum value set includes a fifth value used for the first access category, a sixth value used for the second access category, a seventh value used for the third access category, and an eighth value used for the fourth access category, and

wherein the first CW maximum value set includes a ninth value used for the first access category, a tenth value used for the second access category, an eleventh value used for the third access category, and a twelfth value used for the fourth access category.

7. The method of claim 6 , wherein the second AIFS value set includes a thirteenth value used for the first access category, a fourteenth value used for the second access category, a fifteenth value used for the third access category, and a sixteenth value used for the fourth access category,

wherein the second CW minimum value set includes a seventeenth value used for the first access category, an eighteenth value used for the second access category, a nineteenth value used for the third access category, and a twentieth value used for the fourth access category, and

wherein the second CW maximum value set includes a twenty-first value used for the first access category, a twenty-second value used for the second access category, a twenty-third value used for the third access category, and a twenty-fourth value used for the fourth access category.

8. The method of claim 7 , wherein each of the first to fourth values is configured to be greater than each of the thirteenth to sixteenth values configured in the corresponding access category,

wherein each of the fifth to eighth values is configured to be greater than each of the seventeenth to twentieth values configured in the corresponding access category, and

wherein each of the ninth to twelfth values is configured to be greater than each of the twenty-first to twenty-fourth values configured in the corresponding access category.

9. A wireless device using a method for transmitting an uplink frame in a wireless LAN system, the wireless device comprising:

a transceiver transceiving radio signals; and

a processor being operatively connected to the transceiver,

wherein the processor is configured:

to configure a backoff counter for a contention-based channel access based on first parameter information for the multi-users, after a first trigger frame for uplink transmission of multi-users is received from an access point (AP),

to perform a countdown operation based on the backoff counter configured based on the first parameter information;

to suspend the countdown operation for transmitting a trigger-based uplink frame as a response to a second trigger frame, after the second trigger frame is received, and

to resume the suspended countdown operation, if an acknowledgement (ACK) frame used for the trigger-based uplink frame is not received.