Method and apparatus for accessing channel

A STA performing a channel access, the STA comprising:

• a radio frequency (RF) unit configured to transmit or receive radio signal;
• a processor operatively connected to the RF unit and configured to:
• switch an operation in a power saving mode, to an awake state from a doze state during a beacon interval;
• transmit an uplink frame requesting enhanced distributed channel access (EDCA) set determination information through a first channel access to an access point (AP), if the STA is switched to the awake state,
• wherein the first channel access is performed based on a previously stored EDCA parameter set;
• monitor a channel access parameter frame including the EDCA set determination information for a changed EDCA parameter set,
• wherein the changed EDCA parameter set is changed by the AP, and wherein the channel access parameter frame is transmitted during the beacon interval;
• receive the channel access parameter frame from the AP;
• and
• perform a second channel access by using the changed EDCA parameter set determined based on the EDCA set determination information.