The present disclosure provides channel sensing in an efficient manner in a cognitive radio MAC protocol and improves channel utilization. Proposed is an Adaptive Channel Sensing (ACS) for variably sensing a channel in accordance with a Fixed Channel Sensing (FCS) and a channel state so as to perform the channel sensing in an efficient manner while reducing the power consumption of a terminal Further proposed is a self-scheduling mechanism which enables multiple terminals to simultaneously transceive data by means of a slot-based contention on the basis of the results of the FCS and ACS, which are proposed by the present disclosure.