A method for a base station to transmit a channel-state-information reference signal for up to 8 antenna ports includes mapping, in accordance with a predetermined pattern, the channel-state-information reference signal for up to 8 antenna ports onto a data region of a downlink subframe having an extended cyclic prefix (CP) structure, and transmitting the downlink subframe onto which the channel-state-information reference signal for up to 8 antenna ports has been mapped; and, in the predetermined pattern, the channel-state-information reference signal for up to 8 antenna ports in mapped onto 2 OFDM symbols on the data region of the downlink subframe, with a definition for mapping onto at least one of 4 subcarrier wave positions in each of the 2 OFDM symbols, and the 4 subcarrier wave positions defined in the predetermined pattern can be disposed at 3 subcarrier wave intervals.