A base station in a carrier aggregation communication network, comprising: a secondary component carrier updating unit configured to update a secondary component carrier for a terminal, comprising a reconfiguration information transmission unit configured to transmit to the terminal "Radio Resource Control" reconfiguration information comprising radio resource configuration information of an updated secondary component carrier for configuring the updated secondary component carrier, wherein mobility control information is not included in the "Radio Resource Control" reconfiguration information, the updated secondary component carrier being configured without reconfiguring of MAC or updating of security key, the secondary component carrier updating unit is further configured to update a secondary component carrier for a terminal by adding a new secondary component carrier or replacing an old secondary component carrier with a new secondary component carrier for the terminal, the component carrier to be used by the terminal is determined at least according to a rule that is decided by a distribution mode in the case that a distribution of coverage range of different available carriers corresponding to the position of the terminal accords with the predetermined distribution mode, wherein the predetermined distribution mode and corresponding rule is one of: the predetermined distribution mode is that the coverage ranges of different available carriers are substantially the same, and the rule comprises taking each available carrier as a candidate component carrier; the predetermined distribution mode is that there exists at least one available carrier the coverage range of which is substantially contained within the coverage range of at least one other available carrier, and the rule comprises determining a candidate component carrier at least according to the size of the coverage range of each available carrier; and the predetermined distribution mode is that there exist at least two available carriers the coverage ranges of which are substantially not coincident with each other nor contained one in the other but overlapped with each other, and the rule comprises determining a candidate component carrier at least according to a position where the terminal is located and a moving direction and moving speed of the terminal. a secondary component carrier updating unit configured to update a secondary component carrier for a terminal, comprising a reconfiguration information transmission unit configured to transmit to the terminal "Radio Resource Control" reconfiguration information comprising radio resource configuration information of an updated secondary component carrier for configuring the updated secondary component carrier, wherein mobility control information is not included in the "Radio Resource Control" reconfiguration information, the updated secondary component carrier being configured without reconfiguring of MAC or updating of security key, the secondary component carrier updating unit is further configured to update a secondary component carrier for a terminal by adding a new secondary component carrier or replacing an old secondary component carrier with a new secondary component carrier for the terminal, the component carrier to be used by the terminal is determined at least according to a rule that is decided by a distribution mode in the case that a distribution of coverage range of different available carriers corresponding to the position of the terminal accords with the predetermined distribution mode, wherein the predetermined distribution mode and corresponding rule is one of: the predetermined distribution mode is that the coverage ranges of different available carriers are substantially the same, and the rule comprises taking each available carrier as a candidate component carrier; the predetermined distribution mode is that there exists at least one available carrier the coverage range of which is substantially contained within the coverage range of at least one other available carrier, and the rule comprises determining a candidate component carrier at least according to the size of the coverage range of each available carrier; and the predetermined distribution mode is that there exist at least two available carriers the coverage ranges of which are substantially not coincident with each other nor contained one in the other but overlapped with each other, and the rule comprises determining a candidate component carrier at least according to a position where the terminal is located and a moving direction and moving speed of the terminal. the predetermined distribution mode is that the coverage ranges of different available carriers are substantially the same, and the rule comprises taking each available carrier as a candidate component carrier; the predetermined distribution mode is that there exists at least one available carrier the coverage range of which is substantially contained within the coverage range of at least one other available carrier, and the rule comprises determining a candidate component carrier at least according to the size of the coverage range of each available carrier; and the predetermined distribution mode is that there exist at least two available carriers the coverage ranges of which are substantially not coincident with each other nor contained one in the other but overlapped with each other, and the rule comprises determining a candidate component carrier at least according to a position where the terminal is located and a moving direction and moving speed of the terminal.