Method and apparatus for transmitting uplink frame in wireless LAN

A station (STA) for transmitting an uplink frame in wireless local network (WLAN), comprising:

• a radio frequency (RF) unit configured to transmit or receive a radio signal;
• and
• a processor operatively connected to the RF unit,
• wherein the processor is configured to perform:
• receiving a downlink physical layer protocol data unit (PPDU) from an access point (AP) through a downlink oriented channel;
• performing a first channel switching from the downlink oriented channel to a normal channel based on information on a transmission opportunity (TXOP) duration for transmitting the downlink PPDU, when indication information of a reception STA of the downlink PPDU does not indicate the STA and there is an uplink frame which is pending on the STA;
• performing a channel access for transmitting the uplink frame through the normal channel on a time resource that corresponds to the TXOP duration;
• and
• performing a second channel switching from the normal channel to the downlink oriented channel based on the information on the TXOP duration,
• wherein the downlink oriented channel is used for a transmission of the downlink PPDU based on non-contention by the AP and a transmission of a response frame in response to the downlink PPDU by the STA,
• wherein the downlink oriented channel is not used for a transmission of an independent uplink frame by the STA, and
• wherein the independent frame is an uplink frame which is not the response frame among uplink frames transmitted from the STA to the AP.