Method and apparatus for efficiently utilizing HARQ processes for semi-persistent and dynamic data transmissions

1. A method of controlling an allocation of hybrid automatic repeat request (HARQ) resources during a semi-persistent scheduling session for a wireless transmit/receive unit (WTRU), the method comprising:

reserving a subset of a plurality of HARQ process identifications (IDs) for semi-persistent scheduling;

determining a first HARQ process ID from the subset of the plurality of HARQ process IDs for a first downlink (DL) transmission associated with an allocation of a semi-persistent resource, the first HARQ process ID being based on at least a system frame number (SFN);

receiving first semi-persistently scheduled data associated with the first HARQ process ID via the allocated semi-persistent resource;

receiving a dynamic allocation associated with the first HARQ process ID via a physical downlink control channel (PDCCH) after the first semi-persistently scheduled data has been successfully received;

attempting to receive dynamically allocated data associated with the first HARQ process ID in accordance with the dynamic allocation;

suspending HARQ processing of the dynamically allocated data upon reaching a subsequent transmission opportunity associated with the semi-persistent resource that utilizes the first HARQ process ID; and

receiving second semi-persistently scheduled data associated with the first HARQ process ID via the allocated semi-persistent resource.

2. The method of claim 1 , further comprising receiving an activation message for the allocation of the semi-persistent resource via the PDCCH.

3. The method of claim 2 , wherein the activation message does not include the first HARQ process ID.

4. The method of claim 1 , further comprising:

sending an acknowledgment indicating receipt of at least one of the first and second semi-persistently scheduled data.

5. The method of claim 1 , wherein the first HARQ process ID is based on at least a plurality of SFNs.

6. The method of claim 1 , further comprising determining a second HARQ process ID for a second DL transmission associated with an allocation of a non-semi-persistent resource based on the second HARQ process ID being received in the allocation of the non-semi-persistent resource.

7. The method of claim 6 , wherein the allocation of the non-semi-persistent resource is received via the PDCCH.

8. The method of claim 1 , further comprising receiving a radio resource control (RRC) message, the RRC message including a configuration for the subset of the plurality of HARQ process IDs.

9. The method of claim 1 , wherein the first HARQ process ID is used after all unreserved HARQ process IDs have been used.

10. The method of claim 1 , wherein the subset of the plurality of HARQ process IDs are used by high priority services.

11. A wireless transmit/receive unit (WTRU), the WTRU comprising:

a processor configured at least to:

reserve a subset of a plurality of hybrid automatic repeat request (HARQ) process identifications (IDs) for semi-persistent scheduling;

determine a first HARQ process ID from the subset of the plurality of HARQ process IDs for a first downlink (DL) transmission associated with an allocation of a semi-persistent resource, the first HARQ process ID being based on at least a system frame number (SFN);

receive first semi-persistently scheduled data associated with the first HARQ process ID via the allocated semi-persistent resource;

receive a dynamic allocation associated with the first HARQ process ID via a physical downlink control channel (PDCCH) after the first semi-persistently scheduled data has been successfully received;

attempt to receive dynamically allocated data associated with the first HARQ process ID in accordance with the dynamic allocation;

suspend HARQ processing of the dynamically allocated data upon reaching a subsequent transmission opportunity associated with the semi-persistent resource that utilizes the first HARQ process ID; and

receive second semi-persistently scheduled data associated with the first HARQ process ID via the allocated semi-persistent resource.

12. The WTRU of claim 11 , wherein the processor is further configured to receive an activation message for the allocation of the semi-persistent resource via the PDCCH.

13. The WTRU of claim 12 , wherein the activation message does not include the first HARQ process ID.

14. The WTRU of claim 11 , wherein the processor is further configured to send an acknowledgment indicating receipt of at least one of the first and second semi-persistently scheduled data.

15. The WTRU of claim 11 , wherein the first HARQ process ID is based on at least a plurality of SFNs.

16. The WTRU of claim 11 , wherein the processor is further configured to determine a second HARQ process ID for a second DL transmission associated with an allocation of a non-semi-persistent resource based on the second HARQ process ID being received in the allocation of the non-semi-persistent resource.

17. The WTRU of claim 16 , wherein the processor is further configured to receive the allocation of the non-semi-persistent resource via the PDCCH.

18. The WTRU of claim 11 , wherein the processor is further configured to receive a radio resource control (RRC) message, the RRC message including a configuration for the subset of the plurality of HARQ process IDs.

19. The WTRU of claim 11 , wherein the processor is further configured such that the first HARQ process ID is used after all unreserved HARQ process IDs have been used.

20. The WTRU of claim 11 , wherein the processor is further configured such that the subset of the plurality of HARQ process IDs are used by high priority services.