Patent ID: 8861463

Claim:
A method of performing an uplink hybrid automatic repeat request (HARQ) in a wireless communication system, the method comprising: receiving, by a user equipment, an uplink grant including an uplink resource allocation and a carrier indicator field, through a downlink component carrier; transmitting, by the user equipment, at least one transport block on a physical uplink shared channel (PUSCH) through an uplink component carrier indicated by the carrier indicator field among a plurality of uplink component carriers by using the uplink resource allocation; and receiving, by the user equipment, a ACK/NACK signal for the transport block through a physical hybrid-ARQ indicator channel (PHICH), wherein a resource of the PHICH is determined according to the carrier indicator field which is used to determine the uplink component carrier for transmitting the transport block among the plurality of uplink component carriers, wherein the resource of the PHICH is identified by a PHICH group and an orthogonal sequence index in a PHICH group, and wherein resources of the PUSCH are mapped to the PHICH group in a forward direction.