Received baseband signals from a plurality of antennas 11 1 to 11 Q are linearly combined through multiplication by weighting coefficients, then a decision signal is delayed for one symbol duration, and the delayed signal is multiplied by a feedback filter coefficient w b * to generate intersymbol interference, which is subtracted from the linearly combined output y(i). The subtracted output is subjected to a signal decision to obtain a decision signal, then the difference between the input into a decision unit 17 and the decision signal is obtained as an error signal e(i), and weighting coefficients w 1 * to w Q * and the feedback filter coefficient w b * are estimated in a parameter estimation part 71 so that the square of the error signal e(i) is minimized. At the transmitting side a transmitted signal is delayed for 1T and is then multiplied by the feedback filter coefficient w b *, then intersymbol interference is subtracted from the transmitted signal to distort it, and the distorted signal is multiplied by the weighting coefficients w 1 * to w Q *, respectively, thereby creating transmitted baseband signals for application to the antennas 11 1 to 11 Q .