Abstract: A method for generating a codebook based on a discrete cosine transform, suitable for an electronic device with a plurality of antennas is provided, including: generating an identity matrix, and the size of the identity matrix is related to the number of antennas of the electronic device; inputting a plurality of column vectors of the identity matrix into a discrete cosine transform formula to calculate a plurality of codeword elements corresponding to the column vectors; generating a plurality of codewords corresponding to the column vectors, the codewords corresponding to the column vectors comprise the codeword elements corresponding to the column vectors; multiplying the codewords by a coefficient related to the number of antennas; determining whether the calculation of all the codewords has been completed; and completing the codebook.