According to an exemplary embodiment of the present invention, a master base station selects a target serving cell in which a state is changed, among the serving cells of at least one slave base station set in the terminal, generates a MAC control element which instructs a state change of the target serving cell, and then directly transmits the MAC control element to the terminal in the case of an uplink asynchronous state between the target slave base station managing the target serving cell and the terminal.