Techniques for sending hybrid automatic repeat request (HARQ) feedback for transmissions received via a plurality of aggregated component carriers are disclosed. A wireless transmit/receive unit (WTRU) receive a plurality of codewords via a plurality of component carriers and decodes the codewords. The component carriers are grouped into a plurality of groups, and the WTRU may generate a bundled positive/negative acknowledgement (ACK/NACK) for each group of component carriers. The WTRU may be assigned a plurality of uplink control channel resources and may implement a channel selection scheme for indicating the ACK/NACKs. The WTRU selects one of the uplink control channel resources, and sets the HARQ feedback based the ACK/NACKs or bundled ACK/NACKs in a way that a different uplink control channel resource is selected and HARQ feedback bits are set differently based on the ACK/NACKs or bundled ACK/NACKs. Each physical uplink control channel (PUCCHs) may be mapped to a particular antenna.