Transmission power control method, mobile communications system and mobile station

A mobile station (11) in a mobile communications system directs a base station (12) to raise a transmission power using identification data, when a reception quality measured by the mobile station (11) is lower than a desired reception quality. The mobile station (11) also directs the base station (12) to lower the transmission power using identification data, when the reception quality measured by the mobile station (11) is higher than the desired reception quality.