According to one embodiment, a method for maintaining a communication between a mobile terminal and a network in a mobile communication system includes: determining whether a state of the mobile terminal is in an unsynchronized state while maintaining a radio resource control (RRC) connected state with the network; performing a random access channel (RACH) procedure for a synchronized state if it is determined that the state of the mobile terminal is in the unsynchronized state while maintaining the RRC connected state with the network; and after performing the RACH procedure, transitioning from the synchronized state to the unsynchronized state with the network while maintaining the RRC connected state with the network when a timer expires.