Patent ID: 8687555

Claim:
A method for transmitting channel status information (CSI) of downlink (DL) multi-carrier transmission, the method comprising: generating the CSI including at least one of a rank indicator (RI), a first precoding matrix index (PMI), a second PMI and a channel quality indicator (CQI) for one or more DL carriers, wherein the CQI is calculated based on precoding information determined by a combination of the first and second PMIs; determining, when two or more CSIs collide with one another in one uplink (UL) subframe of one UL carrier, a CSI to be transmitted on the basis of priority; and transmitting the determined CSI over a UL channel, wherein the CSI is classified into a first group including an RI, a second group including a wideband (WB) first PMI, a third group including a WB CQI, and a fourth group including an SB CQI, and wherein the priority is defined that, if a CSI of the first group or a CSI of the second group collides with a CSI of the third group or a CSI of the fourth group, the CSI of the third or fourth group has low priority and is dropped.