Abstract: Aspect of the disclosure can provide a timer control method that can include receiving, at a first cell, a message of a physical downlink control channel (S1), and starting or restarting a bandwidth part inactivity timer for an activated downlink bandwidth part of the first cell, and starting or restarting a bandwidth part inactivity timer for an activated downlink bandwidth part of the second cell, if it is determined based on the message of the physical downlink control channel that a random access initiated at a second cell is successful (S2).