A mobile communication apparatus configured to communicate with an opposite communication device is provided. The mobile communication apparatus includes a transceiver configured to receive an incoming signal sent from the opposite communication device. The transceiver is configured to produce an interrupt signal upon receiving the incoming signal. The mobile communication apparatus includes a first memory device and a non-volatile second memory device. The mobile communication apparatus includes a controller connected to the transceiver, the first memory device and the second memory device. The controller is configured to perform garbage collection of the second memory device, to load data stored in one of the first memory device and the second memory device into another of the first memory device and the second memory device, to access the first memory device if the transceiver produces the interrupt signal.