To provide a communication system for using a dedicated channel together with spread code selection data of a parallel combination spread spectrum system so as to meticulously control a physical layer.

A downlink transmission rate control decision section 4 of a mobile station adopting the communication system confirms a downlink SIR 3a and transmits first downlink transmission rate control information 4a corresponding to the quality to a modulation section 5 of the dedicated channel, then the modulation section 5 transmits the information 4a to a base station from an antenna 1 via a wireless section 2. Then the downlink transmission rate control decision section 4 confirms the downlink SIR 3a in an interval timing of a transmission timing of the first downlink transmission rate control information 4a and transmits second downlink transmission rate control information 4b corresponding to the quality as spread code selection data 6b to a parallel combination spread spectral section 6. Then the spread section 6 transmits the spread code selection data 6b to the base station from the antenna 1 via the wireless section 2.