A communication apparatus and method include: selecting, as a precoding matrix, one of pre-stored at least one matrix Wi, where i is a natural number, and precoding a data stream desired to be transmitted based on the precoding matrix, wherein each diagonal block, among a plurality of blocks included in each of the at least one matrix Wi, includes a nonzero matrix, the nonzero matrix excluding a zero matrix, and wherein each remaining block among the plurality of blocks, excluding the diagonal blocks, includes the zero matrix