A feedback method of a terminal in a mobile communication system, the method comprising: receiving configuration information for two classes of reference signals, RSs; receiving feedback configuration information; identifying reference antenna port information for the two classes of RSs; receiving RSs of each of the two classes of RSs from a base station; estimating a channel between a plurality of antennas of the base station and a plurality of antennas of the terminal based on channels of the received RSs and a relationship between the channels of the received RSs based on at least one reference antenna port (1000, 1010, 1020) for transmitting received RSs of each of the two classes of RSs with the same antenna configuration which is indicated by the reference antenna port information; and transmitting feedback information on the estimated channel based on the feedback configuration information to the base station, wherein the two classes of RS comprise horizontal direction RSs, CSI-RS-1, and vertical direction RSs, CSI-RS-2, for the plurality of antennas of the base station being arranged 2-dimensionally, wherein a horizontal channel state information reference signal, H-CSI-RS, of the received RSs is used for estimating a horizontal angle between the plurality of antennas of the terminal and the plurality of antennas of the base station and a vertical channel state information reference signal, V-CSI-RS, of the received RSs is used for estimating a vertical angle between the plurality of antennas of the terminal and the plurality of antennas of the base station, wherein the at least one reference antenna port is an overlapped antenna port between at least one antenna port of a horizontal direction RS, CSI-RS-1, and at least one antenna port of a vertical direction RS, CSI-RS-2, and wherein the feedback configuration information instruct the terminal to report a rank indicator, RI, two PMIs i1 and i2 defining precoding matrices and CQI to the eNB, wherein i1 indicates beamforming vector candidates selectable for the estimated channel and i2 selects a beamforming vector for the estimated channel. receiving configuration information for two classes of reference signals, RSs; receiving feedback configuration information; identifying reference antenna port information for the two classes of RSs; receiving RSs of each of the two classes of RSs from a base station; estimating a channel between a plurality of antennas of the base station and a plurality of antennas of the terminal based on channels of the received RSs and a relationship between the channels of the received RSs based on at least one reference antenna port (1000, 1010, 1020) for transmitting received RSs of each of the two classes of RSs with the same antenna configuration which is indicated by the reference antenna port information; and transmitting feedback information on the estimated channel based on the feedback configuration information to the base station, wherein the two classes of RS comprise horizontal direction RSs, CSI-RS-1, and vertical direction RSs, CSI-RS-2, for the plurality of antennas of the base station being arranged 2-dimensionally, wherein a horizontal channel state information reference signal, H-CSI-RS, of the received RSs is used for estimating a horizontal angle between the plurality of antennas of the terminal and the plurality of antennas of the base station and a vertical channel state information reference signal, V-CSI-RS, of the received RSs is used for estimating a vertical angle between the plurality of antennas of the terminal and the plurality of antennas of the base station, wherein the at least one reference antenna port is an overlapped antenna port between at least one antenna port of a horizontal direction RS, CSI-RS-1, and at least one antenna port of a vertical direction RS, CSI-RS-2, and wherein the feedback configuration information instruct the terminal to report a rank indicator, RI, two PMIs i1 and i2 defining precoding matrices and CQI to the eNB, wherein i1 indicates beamforming vector candidates selectable for the estimated channel and i2 selects a beamforming vector for the estimated channel.