Methods and apparatuses are provided for reducing power consumption by early decoding. It is determined whether a predetermined decoding condition is satisfied upon expiration of a time unit in a transmission time interval. Decoding is performed on a signal that has been received through the time unit in the transmission time interval, when the predetermined decoding condition is satisfied. A controller outputs an instruction signal to a RF processor to set to a low-power mode during a remaining time period of the transmission time interval after the time unit in the transmission time interval, when the decoding is successful. Decoding is performed on the signal that has been received through the RF processor upon expiration of a last time unit of the transmission time interval regardless of the predetermined decoding condition, when the time unit is the last time unit in the transmission time interval.