Control channel signaling and acquisition for carrier aggregation

A wireless transmit/receive unit (WTRU) configured, at least in part, to:

• receive a first radio resource control (RRC) message comprising information regarding carrier aggregation, wherein the information regarding carrier aggregation comprises an indication that downlink control information for a first component carrier will be received via a second component carrier;
• receive a physical downlink control channel (PDCCH) transmission on the second component carrier, wherein the PDDCH transmission comprises a downlink grant and an index indicating which component carrier is to be used for carrying a physical downlink shared channel (PDSCH) transmission associated with the downlink grant;
• determine the PDSCH transmission is to be received on a physical first component carrier based on the index included in the PDCCH transmission received on the second component carrier;
• and
• receive the PDSCH transmission on the first component carrier in accordance with the downlink grant included in the PDCCH transmission received on the second component carrier.

A base station configured, at least in part, to:

• determine that downlink control information for a first component carrier is to be transmitted to a wireless transmit receive unit (WTRU) using a physical downlink control channel (PDCCH) of a second component carrier;
• send a first radio resource control (RRC) message comprising information regarding carrier aggregation to the WTRU, wherein the information regarding carrier aggregation comprises an indication that the downlink control information for the first component carrier will be sent to the WTRU via the PDCCH of the second component carrier;
• send a PDCCH transmission to the WTRU on the second component carrier, the PDDCH transmission comprising a downlink grant and an index indicating which component carrier is to be used for carrying a physical downlink shared channel (PDSCH) transmission associated with the downlink grant, wherein the index included in the PDCCH transmission indicates that the first component carrier is to be used by the WTRU for receiving the PDSCH transmission associated with the downlink grant;
• and
• receive the PDSCH transmission on the first component carrier in accordance with the downlink grant included in the PDCCH transmission received on the second component carrier.