An electronic device and a method for operating the electronic device. The electronic device includes: a communication processor configured to support a C-DRX; and a communication circuit configured to switch a first on-duration period to a sleep duration according to expiration of a predetermined time corresponding to an inactivity timer, wherein the communication processor is configured to determine whether to change a length of the sleep duration of the C-DRX, based on a state of the electronic device, control the communication circuit to transmit UE assistance information for changing the length of the sleep duration of the C-DRX, based on the determination, to a network, and control an operation related to the C-DRX of the communication circuit, based on the inactivity timer having a changed predetermined time included in an RRC reconfiguration message received according to an RRC connection with the network. Various other embodiments are possible.