Base station for controlling downlink transmission power during soft hand over

摘要

In soft hand over in a code division multi access mobile radio communication system, interference in a down link caused by transmission from a plurality of base stations for one mobile station, can be restricted. Control of transmission power is performed according to command from the mobile station only in the base station serving as a primary base station which has minimum propagation loss with the mobile station during soft hand over, and the base stations other than the primary base station perform transmission with restricting output. In comparison with the transmission power control performed by the conventional plural base station transmission, interference for the peripheral mobile station can be reduced to achieve higher down link capacity. Also, upon restricting transmission power of the base station other than the base stations having small propagation loss with the mobile station among base station group in soft hand over, by moderately attenuating the transmission power instead of restricting abruptly, degradation of the reception quality can be prevented when error is caused in selection of the base station.