HARQ process utilization in multiple carrier wireless communications
Methods and apparatus utilize hybrid automatic repeat request (HARQ) transmissions and retransmissions that are usable on multiple carriers, i.e. joint HARQ processes. For example, a downlink (DL) shared channel transmission of a joint HARQ process is received on one of the carriers. A first part of an identity of the joint HARQ process is determined by using HARQ process identity data received on a shared control channel. A second part of the joint HARQ process identity is determined using additional information. The joint HARQ process identity is then determined by combining the first part and the second part. A WTRU is provided that is configured to receive the DL shared channel and to make the aforementioned determinations. A variety of other methods and apparatus configurations are disclosed for utilizing joint HARQ processes, in particular in the context of DC-HSDPA.
1. A wireless transmit/receive unit (WTRU) comprising:
receiver configured to receive a first downlink control information (DCI) format that is legacy DCI format that does not include component carrier information;
the receiver further configured to receive a configuration message that indicates that the WTRU is to receive a second DCI format indicating a component carrier; and
the receiver is further configured to receive a HARQ transmission over the indicated component carrier of the second DCI format.
2. The WTRU of claim 1 wherein a physical downlink control channel (PDCCH) search space is associated with the second DCI format.
3. The WTRU of claim 2 wherein the PDCCH search space is a WTRU specific search space.
4. A method for receiving downlink control information at a wireless transmit/receive unit (WTRU), the method comprising:
receiving a first DCI format that is legacy DCI format that does not include component carrier information;
receiving a configuration message that indicates that the WTRU is to receive a second DCI format indicating a component carrier; and
receiving a HARQ transmission over the indicated component carrier of the second DCI format.
5. The method of claim 4 wherein a physical downlink control channel (PDCCH) search space is associated with the second DCI format.
6. The method of claim 5 wherein a PDCCH search space is associated with the at least one second DCI format.
7. The method of claim 5 wherein the PDCCH search space is a WTRU specific search space.
8. An evolved NodeB (eNB) comprising:
a transmitter configured to transmit a first downlink control information (DCI) format that is legacy DCI format that does not include component carrier information;
the transmitter further configured to transmit a configuration message that indicates that a wireless transmit/receive unit (WTRU) is to receive a second DCI format indicating a component carrier; and
the transmitter further configured to transmit a HARQ transmission over the indicated component carrier of the second DCI format.
9. The eNB of claim 8 wherein the at least one circuit transmits the DCI in a physical downlink control channel (PDCCH) search space associated with the at least one second DCI format.
10. The eNB of claim 8 wherein the PDCCH search space is a WTRU specific search space.