When a downlink
communication channel quality is informed of in the downlink
packet communication using a shared channel, the
communication channel quality for each RB that is obtained by dividing a downlink into a plurality of small bands (RBs) is informed of via the uplink. As the downlink band is getting wider, the number of RBs increases and the bands required to inform via the uplink also increases. Then, in the
mobile station, RBs whose the
communication channel quality is at a predetermined threshold or more are selected as a selected group, with the others considered as in the non-selected group, the information indicating which groups do they belong to is generated as a
bitmap, and then the average value, the minimum value and the maximum value of the communication channel quality of the RBs are also obtained. Then the minimum or the maximum value is transmitted as a represented value of the selected group, the average value is transmitted as a representative value of the non-selected group, and also the
bitmap is transmitted to the
base station. At the
base station, the communication channel quality for each RB is restored by replacing the communication channel quality belonging to the selected group by the minimum or the maximum value, and the communication channel quality belonging to the non-selected group by the average value.