determined as the maximum power per antenna in h i is all 0 therefore both w i u2212 1 and w i become the zf precoding matrices regardless of the constant u03b1 i according to the lemma of equation 1 also since the rows in t i whose elements are all 0 and the rows in w i u2212 1 whose rows corresponding to the index of the transmission antenna using the maximum power per antenna are located at the same position the elements of the rows in w i u2212 1 corresponding to the index of transmission antennas using the maximum power per antenna are the same as the elements of the rows in w i corresponding to the index of transmission antennas using the per antenna maximum power also the transmit power of the transmission antenna which has already been determined to transmit with the maximum power per antenna is not affected by the constant u03b1 i the transmit power of a transmission antenna can be represented as the square of 2 norm of the row vector of w i and assuming that the transmit power is the same as the maximum power per antenna p n t the constant u03b1 i can be calculated equation 4 represents the equation for obtaining the constant u03b1 i in equation 4 a represents the row vector of w i u2212 1 and b the row vector of t i the transmit power of another transmission antenna can be determined as the maximum power per antenna by calculating the constant u03b1 i by using equation 4 the steps s 110 through s 130 are repeated until the condition i n t u2212 k 1 is satisfied in step s 140 the condition.