A mobile terminal apparatus estimates downlink channel states using respective reference signals included in downlink signals from plural cells; selects PMIs (Precoding Matrix Indicators) using a codebook based on the channel states; estimates a phase difference between the cells based on the selected PMIs or the channel states; and transmits information of the phase difference and the selected PMIs to radio base station apparatuses of the respective cells. A radio base station apparatus receives an uplink signal including a PMI and the information of the phase difference between the cells; multiplies a transmission signal by a precoding weight corresponding to the PMI; adjusts the phase difference between the cells with use of the information of the phase difference between the cells; and transmits the transmission signal to a radio base station apparatus of another cell by coordinated multi-point transmission.