Patent ID: 8774037

Claim:
A method of a user equipment feeding back channel state information in a wireless communication system, the method comprising: receiving a reference signal from a base station; generating first channel state information by measuring the reference signal; generating second channel state information based on the first channel state information; and transmitting the first channel state information and the second channel state information to the base station, wherein the first channel state information is channel state information of a single user single cell Multi-input Multi-Output (MIMO) mode, and the second channel state information is channel state information of a multi-user MIMO (MU-MIMO) mode or a Cooperative Multiple Points Transmission and Reception (COMP) mode, wherein each of the first channel state information and the second channel state information includes a Channel Quality Indication (CQI), a Precoding Matrix Index (PMI), and a Rank Indicator (RI), and wherein the first channel state information includes a first PMI indicative of a first precoding matrix, the second channel state information includes a second PMI indicative of a second precoding matrix, and the second precoding matrix includes some of or all column vectors of the first precoding matrix.