Method and device for performing active scanning

A station (STA) for performing active scanning, the STA comprising:

• a radio frequency (RF) unit configured to transmits and receive radio signals;
• and
• a processor operatively coupled to the RF unit and configured to:
• transmit to an access point (AP), a probe request frame including channel monitoring type information in a scanning channel;
• determine whether the scanning channel is in a busy state until MinimumChannelTime,
• determine whether a PPDU including a valid physical layer convergence procedure (PLCP) header is received in the scanning channel until the MinimumChannelTime, and
• determine a time for monitoring a probe response frame transmitted by the AP in the scanning channel based on whether the PPDU is received until the MinimumChannelTime and the channel monitoring type information, when the scanning channel is in the busy state,
• wherein the channel monitoring type information includes information related to a type of the STA to monitor the probe response frame in the scanning channel,
• wherein the time for monitoring the probe response frame is determined as the MinimumChannelTime when the PPDU is not received in the scanning channel until the MinimumChannelTime and the channel monitoring type information indicates a first type, and
• wherein the time for monitoring the probe response frame is determined as a MaxChannelTime when the PPDU is not received in the scanning channel until the MinimumChannelTime and the channel monitoring type information indicates a second type.