The present invention relates to a method and a device for selecting a
cell in a mobile communication
system and, more particularly, to a method and a device for selecting a
cell for transmitting data, by a
base station, not only in a licensed
frequency band but in an unlicensed
frequency band. In order to achieve the described task, a method for configuring a
cell of a
base station in a mobile communication
system according to an embodiment of the present invention comprises the steps of: connecting with a terminal through a first cell of a licensed band; transmitting, to the terminal, a message for configuring multiple second cells in an
unlicensed band through the first cell; and monitoring the configured multiple second cells in the
unlicensed band, wherein the number of the multiple second cells exceeds the number of cells, a Carrier Aggregation (CA) of which the terminal can support. The present disclosure relates to a 5G or a pre-5G communication
system to be provided in order to support a higher
data transmission rate after a 4G communication system such as an LTE.