power of the up control instruction from the base station having small propagation loss to the mobile station is greater than the reception power of the up control instruction from the base station having large propagation loss to the mobile station. When a difference of the propagation losses is large, probability of reception failure of the up control instruction from the base station having large propagation loss becomes high. In such case, the transmission power in the uplink is mainly controlled by up control instruction from the base station having small propagation loss. Therefore, no significant problem will be arisen. On the other hand, when the difference of the propagation losses is small, it is important to control the up transmission power according to both base stations. Inminimum power Pmin (steps S211, S212). Then, the process is repeated from the step S202.
In this method, upon timing of initiation of the soft hand-over, since the initial values of the down transmission power of the primary base station and the auxiliary base station are different, there is a difference |P1−P2| between the down transmission power P1 of the primary base station and the down transmission power P2 of the auxiliary base station. On the other hand, upon failure of reception of the down control instruction in one or more base stations, the difference |P1−P2| of these transmission powers P1 and P2 can be increased. However, in a portion of control through steps S203 to S206, namely a portion for increasing and decreasing the down transmission power by