Base station, terminal apparatus, radio communication system, and communication method

The base station performs radio communication of a time-division-duplex scheme with a terminal apparatus, using any of a plurality of channels included in each of a plurality of frequency bands, and includes: a channel selector that selects a plurality of use channels to be used for the radio communication; a transmitter that transmits a downlink signal to the terminal apparatus; and a receiver that receives an uplink signal from the terminal apparatus. The transmitter transmits, using at least one of the plurality of use channels, the downlink signal in a transmission interval of the downlink signal, and the receiver receives the uplink signal in the transmission interval of the downlink signal, using another one of the plurality of use channels that is not adjacent to the at least one of the use channels.