A communications system for exchange of information between communications apparatuses by a multicarrier transmission mode using a plurality of subcarriers, includes a transmission data generator configured to generate frequency band information indicating which frequency band is to be used for transmission of data information between said communication apparatuses; a transmitter configured to transmit the frequency band information by using a specific frequency band which is set from among a plurality of frequency band assigned to the communications system, and to transmit data information by using at least one frequency band set from among said plurality of frequency bands; a receiver configured to receive the frequency band information by using the specific frequency band, whereby the specific frequency band among said plurality of frequency bands and at least one frequency band set among the plurality of frequency bands, other than the specific frequency band, are made variable to avoid overlap.