Provided are a base station, a terminal, a band allocation method, and a downlink data communication method in which a mapping method for synchronization signals and report signals is implemented with high resource usage efficiency when a first system in which an independent single communication is allocated to a unit band co-exists with a second system in which a plurality of unit bands can be allocated to a single communication. In a base station (200), an OFDM signal generation unit (225) maps primary synchronization channel (P-SCH), secondary synchronization channel (S-SCH), primary broadcast channel (P-BCH), and dynamic broadcast channel (D-BCH), which can be decoded by both an LTE terminal and an LTE+ terminal, to some of a plurality of unit bands available to the station itself. The OFDM signal generation unit (225) also maps D-BCH+, which can be decoded only by an LTE+ terminal, to all of the plurality of unit bands to produce a multiplexed transmission signal. When the terminal which has transmitted terminal capability information is an LTE+ terminal, a control unit (265) transmits a band movement indication which indicates changes in the reception band to that terminal.