p o th subframe in step 419 since these operations are not associated with the interaction between the ue and enb it is not necessary for the ue to stop the operations at a predetermined time point the operations include stop monitoring phcch physical downlink control channel in scell stop transmitting srs sounding reference symbol the ue executes third operations to be performed at the second time point i e p o th subframe in step 421 these operations include stopping a reporting of csi since this operation is associated with the interaction between the ue and enb the ue should stop the operations at a predetermined time point to avoid performance degradation of the enb caused by not stopping the corresponding operations for example if the enb is not aware that the ue has stopped reporting channel state information the enb may fail scheduling due to the misjudgment on the ue 39 s channel state all of the operations may be performed by following the above described procedure fig5 is a flowchart illustrating ue procedure for performing first operations in a secondary carrier activation deactivation method according to an exemplary embodiment of the present invention referring to fig5 the ue receives activation deactivation mac ce having an 8 bit bitmap in n th subframe in step 501 each bit of the bitmap of mac ce indicates whether to activate or.