The invention is directed to a radio unit contained within a housing of a wireless communication device or system, the radio unit including: a signal processing unit for performing one or more wireless protocol processing functions; a radio-frequency (RF) front end unit coupled to the signal processing unit; and a power unit coupled to the RF front end unit, wherein the power unit completely powers down the RF front end unit when the signal processing unit is in a sleep mode, and powers up the RF front end unit at a predetermined time before an anticipated reception of a RF signal transmitted by an external device.