A wireless device includes a radio-frequency module, a modem module, and a control unit. The radio-frequency module and the modem module operate either in a first operation mode or in a second operation mode. The control unit, coupled to the RF and the modem module, generates a control signal to indicate to the RF and the modem module to operate in the first operation mode or to operate in the second operation mode. A first set of signal formats corresponding to the first operation mode is a superset of a second set of signal formats corresponding to the second operation mode, and a first power consumption corresponding to the first operation mode is higher than a second power consumption corresponding to the second operation mode.