A mobile station includes a reception quality generating unit that generates the reception quality based on a reception quality measured for data transmitted after transmission of a preamble signal. The mobile station is in a mobile communication system in which, a radio base station transmits the data after transmission of the preamble signal and, after transmission of a signal and before transmission of a subsequent preamble signal from the radio base station, the mobile station transmits to the radio base station, reception quality of the signal transmitted from the radio base station, whereby a transmission parameter for data transmitted to the mobile station after transmission of the subsequent preamble signal can be changed.