To reduce the power consumption while enhancing the utilizing efficiency of a transmission frequency band of an OFDM signal by using number of sub carriers for transmission of information through an outgoing channel more than number of sub carriers for transmission of information through an incoming channel in the radio communication system where information is sent by orthogonal frequency division multiplex(OFDM) signals.

In the radio communication system with a non-symmetry characteristic where OFDM signals are used for transmission, number of sub carriers for transmission of information through an outgoing channel 5 is more than number of sub carriers for transmission of information through an incoming channel 4. In the case of employing a same modulation system for the outgoing channel 5 and the incoming channel 4, a ratio of number of sub carriers of both the channels for transmission of information is selected to be a ratio of transmission rates. The low power consumption and miniaturization of radio terminals 1 and improvement of communication quality of the incoming channel or the like are expected by realizing the radio communication system where the transmission rate of the incoming channel 4 is lower than the transmission rate of the outgoing channel 5 in this way.