Disclosed is a method for determining precoding matrix based on an open-loop MIMO scheme, which can enhance a diversity gain at a static communication environment or a low-mobility communication environment. The method for determining precoding matrix applies a first precoding matrix to downstream data to transmit the downstream data through a plurality of antennas, the first precoding matrix being selected from a codebook which comprises a plurality of precoding matrixes, and changes the first precoding matrix to a second precoding matrix per predetermined period, and applying the second precoding matrix to the downstream data to transmit the downstream data through the antennas. The second precoding matrix is a precoding matrix corresponding to an index which has been shifted by a certain value from an index of the first precoding matrix in a direction where an index of a precoding matrix increases, in the codebook.