Disclosed is a relay. The relay includes: a reception unit configured to receive signals from a transmitter; a processor configured to estimate a channel with respect to the transmitter based on a pilot signal of the transmitter among receiving signals, remove the pilot signal from among the received signals, amplify the signals without the pilot signal according to the estimated channel, and insert a pilot signal of the relay into the amplified signals; and a transmitter transmitting the signals including the pilot signal of the relay under the control of the processor.