1. A decoding method by a user equipment (UE), the method comprising:receiving a downlink control channel;
receiving a reference signal in respective physical resource block (PRB) pairs;
performing a correlation operation between a first sequence for the reference signal and a second sequence for a predetermined reference signal for decoding the downlink control channel;
comparing a correlation value in accordance with the correlation operation with a first threshold value; and
performing blind decoding of a search space for the downlink control channel in a PRB pair among the PRB pairs based on the correlation value corresponding to the PRB pair being greater than the first threshold value,
wherein the first threshold value is adjusted based on a comparison result of the correlation value and the first threshold value.