Patent ID: 8144808

Claim:
A communication apparatus for a communication between a transmitter having eight transmit antennas and a receiver having at least one receive antenna, the communication apparatus comprising: a codebook storage unit configured to store at least one matrix W i comprising eight rows, where i is a natural number; a precoder configured to precode a data stream desired to be transmitted based on one of the stored at least one matrix W i ; and an information receiver configured to receive information associated with a matrix selected by the receiver from the stored at least one matrix W i , wherein each diagonal block, among a plurality of blocks included in each of the at least one matrix W i , comprises a nonzero matrix, the nonzero matrix excluding a zero matrix, wherein each remaining block among the plurality of blocks, excluding the diagonal blocks, comprises the zero matrix, and wherein the precoder is further configured to precode the data stream based on a precoding matrix generated based on information associated with the selected matrix.