Repeater System having anti-oscillation function and auto shutdown function when no user exist and control method therefor

PURPOSE: A repeater system having an oscillation preventing function and a reverse output automatic intercepting function is provided to intercept a reverse output, in a time zone when subscriber exist in a repeater service area or when a reverse oscillation is sensed, so as to prevent capacity reduction of a base station transceiver system and to protect a receiving path. CONSTITUTION: A duplexer(400) transmits data transceived from an external base station transceiver system to a corresponding path. A transmitter(100) amplifies a signal received from the duplexer(400), and outputs the amplified signal as a service frequency. A duplexer(600) transmits an output signal of the transmitter(100) to a mobile station of a corresponding service area, and receives a signal transmitted from the mobile station. A receiver(500) amplifies the signal received in the duplexer(600), and outputs the amplified signal. A controller(200) is coupled with the output signal of the receiver(500) to sense a power level of the receiver(500). If the power level is over the first reference value for the first time or if the power level is under the second reference value for the second time, the controller(200) does not transmit the output signal of the receiver(500) to the duplexer(400).