US Patent 11917684 Channel access procedure by apparatus in unlicensed band

Provided are a method of performing a channel access procedure by an apparatus in an unlicensed band, and an apparatus using same method. The apparatus determines a contention window size (CWS) and performs a channel access procedure with respect to a first channel on the basis of the determined contention window size. The contention window size may be adjusted on the basis of feedback information relating to a second channel. When a transmission history of the second channel, which is to be reflected in determining the contention window size, does not exist, the contention window size may be determined to be a minimum CWS value in a specific channel access priority class.