A base station (BS) operated in an unlicensed band configures a first energy detection threshold for a discovery signal and a second energy detection threshold for data, and performs energy detection. The BS transmits the discovery signal to a user equipment in the unlicensed band if a detected energy based on the energy detection is less than the first energy detection threshold. Further, the BS transmits the data to the user equipment in the unlicensed band if the detected energy based on the energy detection is less than the second energy detection threshold. The first energy detection threshold for the discovery signal is higher than the second energy detection threshold for the data.