A reference signal (RS) transmission system to transmit a channel state information (CSI) RS for extraction of CSI to a relay and a macro terminal is disclosed. The base station transmits information on a sub frame containing the CSI RS to the relay or the macro terminal. The macro terminal and the relay receive the CSI RS using the information on the sub frame. The macro terminal and the relay extract the CSI using the CSI RS and transmit the extracted CSI to the base station.