Patent ID: 8611243

Claim:
A method for transmitting channel status information (CSI) of downlink transmission via uplink in a wireless communication system, the method comprising: transmitting a joint-coded rank indicator (RI) and a first wideband (WB) precoding matrix indicator (PMI) at a first subframe; and transmitting a wideband channel quality indicator (WB CQI) and a second WB PMI at a second subframe; wherein a user equipment (UE) preferred precoding matrix is indicated by a combination of the first WB PMI and the second WB PMI, and if an RI of the joint-coded RI and the first WB PMI is Rank-1 or Rank-2, the first WB PMI of the joint-coded RI and the first WB PMI indicates one index of a subset having 8 indexes from among 16 indexes of the first WB PMI of a precoding codebook.