Patent ID: 8787281

Claim:
A base station apparatus comprising: a control information generation section configured to generate, per fundamental frequency block, a downlink control information piece for demodulating a data channel that is transmitted on each of a plurality of fundamental frequency blocks assigned to a user terminal; a determining section configured to determine, per fundamental frequency block, a search space which is a candidate area where the downlink control information piece is arranged; and a transmission section configured to transmit a downlink control channel in which the search space containing the downlink control information piece is arranged, wherein: the control information generation section arranges respective downlink control information pieces corresponding to the fundamental frequency blocks in the downlink control channel of a specific fundamental frequency block among the fundamental frequency blocks; and using at least a fundamental frequency block-specific offset value out of the fundamental frequency block-specific offset value and a user terminal-specific offset value, the determining section distributes positions of search spaces such that the search spaces are separate between the fundamental frequency blocks and between user terminals.