Patent ID: 8797977

Claim:
A mobile communication system comprising: a base station apparatus and a mobile station apparatus, wherein the base station apparatus is configured to transmit, to the mobile station apparatus, downlink data on a plurality of Physical Downlink Shared Channels (PDSCHs) in a plurality of downlink component carriers in a subframe, the base station apparatus is configured to transmit, to the mobile station apparatus, control information which is used for assigning a Physical Uplink Shared Channel (PUSCH) in an uplink component carrier, the control information being transmitted on a Physical Downlink Control Channel (PDCCH) in a downlink component carrier among the plurality of downlink component carriers, the mobile station apparatus is configured to transmit, to the base station apparatus, uplink data on the Physical Uplink Shared Channel (PUSCH) in the uplink component carrier assigned by using the control information received on the Physical Downlink Control Channel (PDCCH) in the downlink component carrier, and the base station apparatus is configured to transmit, to the mobile station apparatus, a positive acknowledgment or a negative acknowledgment for the uplink data, the positive acknowledgment or the negative acknowledgment being transmitted on a Physical Hybrid ARQ Indicator Channel (PHICH) in a same downlink component carrier as the downlink component carrier in which the control information which is used for assigning the Physical Uplink Shared Channel (PUSCH) in the uplink component carrier is transmitted on the Physical Downlink Control Channel (PDCCH).