The provided is a method and apparatus for adding a WLAN carrier to an E-UTRAN carrier at a radio access network (RAN) level to transmit and receive data. The method may include: receiving, from a base station, additional configuration indication information for additionally configuring a WLAN carrier; additionally configuring the WLAN carrier on the basis of the additional configuration indicating information; and attempting WLAN associating through the WLAN carrier using UE identification information, wherein a WLAN end transmits confirmation information for the WLAN association of the UE to the base station.