. Furthermore, the downlink (PDSCH) and uplink (PUSCH) resource assignments and data transmission support the following mechanisms: (1) the PDCCH on a component carrier assigns PDSCH resources on the same component carrier and PUSCH resources on a single-linked uplink component carrier, i.e., same coding, CCE-based resource mapping, and DCI formats, are used on each component carrier; (2) the PDCCH on a component carrier can assign PDSCH or PUSCH resources in one or multiple component carriers using the carrier indicator field, where 3GPP LTE Rel-8 DCI formats are extended with to 3-bit carrier indicator field, and PDCCH structure, i.e., modulation and coding and CCE-based resource mapping, is reused. The presence of a carrier indicator field is semi- statically configured. For downlink HARQ feedback, PHICH physical transmission aspects such as orthogonal code design, modulation, scrambling sequence, and mapping to resource elements are maintained the same. The PHICH is transmitted only on the downlink component carrier that was used to transmit the uplink grant. If the number of downlink component carriers are more than or equal to the number of uplink component carriers and no carrier indicator field is used, the 3GPP LTE Rel-8 PHICH resource mapping principle is reused [21]. In the uplink, the HARQ ACK/NACK, scheduling request, and channel state information on PUCCH will function according to the following rules: (1) the Rel-10 PUCCH design can support up to five component carriers in the downlink; (2) the HARQ ACK/NACK on PUCCH is associated with downlink transmission on PDSCH; (3) the HARQ feedback for a UE can be transmitted on PUCCH in the absence of PUSCH transmission. In general, transmission of one HARQ ACK/NACK for each downlink component carrier transport block and limited transmission of ACK/NACK for downlink component carrier transport blocks (when power is limited) are supported. The design of the ACK/ NACK resource allocation takes into consideration the performance and power control aspects witho