Base station and control method thereof

A base station in a mobile communication system, comprising:

• a controller including at least one processor, the controller configured to cause the base station to:
• communicate with a radio terminal wirelessly connected to the base station;
• receive, from the radio terminal, a capability message indicating a communication capability of the radio terminal, wherein the capability message includes support band information of a range of frequencies at which the radio terminal is capable of using for radio communications;
• receive, from the radio terminal, a measurement message including measurement information indicating downlink measurement results performed by the radio terminal, wherein the measurement message is different message from the capability message;
• transfer the support band information and the measurement information by a single message to another base station via a network interface, wherein the support band information and the measurement information are used for determining, by the another base station, at least one cell to be added among plural cells of the another base station;
• receive message on a result of determination related to the at least one cell to be added in the another base station, from the another base station via the network interface, wherein the result of determination is based on the support band information and the measurement information;
• and
• after receiving the message on the result of the determination from the another base station, continue communication between the base station and the radio terminal even when the at least one cell of the another base station is added.