A method of transmitting data signals comprising a shortened downlink shared channel (sPDSCH) by a base station in a wireless access system supporting an unlicensed band, the method includes performing a carrier sensing to check whether the unlicensed band is in an idle state or not; and transmitting, to a user equipment (UE), the data signals comprising the sPDSCH based on the carrier sensing via the unlicensed band during a channel occupancy time; wherein the sPDSCH is transmitted in a first time interval or a second time interval following the first time interval, wherein the first time interval starts from a starting point of the transmission of the data signal, and wherein the second time interval ends at a subframe boundary of a licensed band.