Patent ID: 8787275

Claim:
A base station apparatus comprising: an assigning section configured to assign a downlink control channel for a terminal, for which one or multiple component carriers (CC(s)) are configured, to a control channel element (CCE) in a first search space comprised of a plurality of CCEs, wherein the downlink control channel includes resource assignment information indicating a resource allocated to the terminal in a component carrier n (CC n ) out of the configured CC(s); and a transmitting section configured to transmit the downlink control channel to the terminal on the CCE, wherein the first search space, in which the downlink control channel including the resource assignment information indicating the resource allocated in the CC n is assigned, is comprised of the plurality of CCEs depending on the value of n, and wherein a CCE number that defines an end position of the first search space for the CC n and a CCE number that defines a start position of a second search space for a component carrier n+1(CC n+1 ) are consecutive, the second search space being different from the first search space.