To assign a physical channel even if data modulation systems for respective channels to be selected based on the circuit quality are different.

An MCS (Modulation Coding Scheme) selection part 153 determines a communication terminal which transmits a packet based on a report value from each communication terminal, and selects a suitable modulation system and encoding rate out of an MCS selection table 154 based on the report value. At this time, if a destination device requests data of a plurality of service classes, the MCS selection part 153 selects a modulation system whose number of multi value is the lowest as a data modulation system for each service class. The MCS selection part 153 selects the encoding rate so as to maintain the transmission rate.

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