A base station comprising: a data control circuitry configured to process a transmission signal to be simultaneously transmitted to a plurality of mobile terminals; a modulator circuitry (102A...102Nv) configured to modulate the transmission signal processed by the data control circuitry; a radio frequency modulator circuitry (103A...103Nv) configured to modulate the transmission signal modulated by the modulator circuitry into a radio frequency transmission signal; and a plurality of antennas (111A...111Nb) configured to wirelessly transmit the radio frequency transmission signal to the plurality of mobile terminals, wherein when a number of the plurality of mobile terminals to which the transmission signal is to be transmitted is Nv and a number of the plurality of antennas is Nb, the data control circuitry is configured to multiply the transmission signal by a precoding matrix, wherein multiplying the transmission signal by the precoding matrix comprises: generating a channel matrix H which is equal to Nv × Nb; triangular-factorizing a channel correlation matrix H × H*, wherein * represents a complex conjugate transpose, whereby a lower triangular matrix L is obtained; obtaining a new lower triangular matrix L new by multiplying each element l ij of the lower triangular matrix L by 1/gi, wherein i is a row index and j is a column index, and wherein gi is a reception gain associated with the ith mobile terminal of the Nv mobile terminals and setting the the inverse matrix L new -1 of the new lower triangular matrix L new as the precoding matrix. a data control circuitry configured to process a transmission signal to be simultaneously transmitted to a plurality of mobile terminals; a modulator circuitry (102A...102Nv) configured to modulate the transmission signal processed by the data control circuitry; a radio frequency modulator circuitry (103A...103Nv) configured to modulate the transmission signal modulated by the modulator circuitry into a radio frequency transmission signal; and a plurality of antennas (111A...111Nb) configured to wirelessly transmit the radio frequency transmission signal to the plurality of mobile terminals, wherein when a number of the plurality of mobile terminals to which the transmission signal is to be transmitted is Nv and a number of the plurality of antennas is Nb, the data control circuitry is configured to multiply the transmission signal by a precoding matrix, wherein multiplying the transmission signal by the precoding matrix comprises: generating a channel matrix H which is equal to Nv × Nb; triangular-factorizing a channel correlation matrix H × H*, wherein * represents a complex conjugate transpose, whereby a lower triangular matrix L is obtained; obtaining a new lower triangular matrix L new by multiplying each element l ij of the lower triangular matrix L by 1/gi, wherein i is a row index and j is a column index, and wherein gi is a reception gain associated with the ith mobile terminal of the Nv mobile terminals and setting the the inverse matrix L new -1 of the new lower triangular matrix L new as the precoding matrix. generating a channel matrix H which is equal to Nv × Nb; triangular-factorizing a channel correlation matrix H × H*, wherein * represents a complex conjugate transpose, whereby a lower triangular matrix L is obtained; obtaining a new lower triangular matrix L new by multiplying each element l ij of the lower triangular matrix L by 1/gi, wherein i is a row index and j is a column index, and wherein gi is a reception gain associated with the ith mobile terminal of the Nv mobile terminals and setting the the inverse matrix L new -1 of the new lower triangular matrix L new as the precoding matrix.