A terminal device of a radio communication system configured to communicate with a base station device using carrier aggregation, the terminal device comprising: a transmission unit configured to transmit a periodic channel state information reporting for a second secondary cell, using a physical uplink control channel in a first secondary cell, transmit the periodic channel state information reporting for the second secondary cell, using a physical uplink shared channel in a third secondary cell, wherein the first secondary cell, the second secondary cell, and the third secondary cell form a Physical Uplink Control Channel, PUCCH, cell group; a receiving unit configured to receive a MAC control element; and a MAC layer processing unit configured to, in a case that the MAC control element indicating activation of the second secondary cell is received in a subframe n, activate the second secondary cell, the MAC layer processing unit configured to activate the second secondary cell corresponds to applying a secondary cell operation including a first action related to the periodic channel state information reporting for the second secondary cell using the physical uplink control channel in the first secondary cell and a second action related to the periodic channel state information reporting for the second secondary cell using the physical uplink shared channel in the third secondary cell, wherein, in a case that the MAC control element indicating activation of the second secondary cell is received in the subframe n, and the first secondary cell is not activating in the subframe n+8, the MAC layer processing unit is configured to apply the first action in the earliest subframe in which the first secondary cell is activated, the earliest subframe being after the subframe n+8, in a case the MAC control element indicating activation of the second secondary cell is received in the subframe n, and the third secondary cell is activated in the subframe n+8, the MAC layer processing unit is configured to apply the second action in the subframe n+8. a transmission unit configured to transmit a periodic channel state information reporting for a second secondary cell, using a physical uplink control channel in a first secondary cell, transmit the periodic channel state information reporting for the second secondary cell, using a physical uplink shared channel in a third secondary cell, transmit a periodic channel state information reporting for a second secondary cell, using a physical uplink control channel in a first secondary cell, transmit the periodic channel state information reporting for the second secondary cell, using a physical uplink shared channel in a third secondary cell, wherein the first secondary cell, the second secondary cell, and the third secondary cell form a Physical Uplink Control Channel, PUCCH, cell group; a receiving unit configured to receive a MAC control element; and a MAC layer processing unit configured to, in a case that the MAC control element indicating activation of the second secondary cell is received in a subframe n, activate the second secondary cell, the MAC layer processing unit configured to activate the second secondary cell corresponds to applying a secondary cell operation including a first action related to the periodic channel state information reporting for the second secondary cell using the physical uplink control channel in the first secondary cell and a second action related to the periodic channel state information reporting for the second secondary cell using the physical uplink shared channel in the third secondary cell, wherein, in a case that the MAC control element indicating activation of the second secondary cell is received in the subframe n, and the first secondary cell is not activating in the subframe n+8, the MAC layer processing unit is configured to apply the first action in the earliest subframe in which the first secondary cell is activated, the earliest subframe being after the subframe n+8, in a case the MAC control element indicating activation of the second secondary cell is received in the subframe n, and the third secondary cell is activated in the subframe n+8, the MAC layer processing unit is configured to apply the second action in the subframe n+8.