Method and apparatus for selecting a transport format combination

1. A method of selecting a transport format combination (TFC) for wireless transmission of data, the method comprising:

determining a recommended modulation and coding scheme (MCS) and a power ceiling for TFC recovery and elimination;

generating a transport format combination set (TFCS);

calculating a power requirement for each TFC in the TFCS based on the number of bits in each TFC and the MCS used in each TFC;

generating an allowed TFCS subset by eliminating any TFC whose power requirement exceeds the power ceiling, and whose MCS exceeds the recommended MCS;

generating a medium access control (MAC) protocol data unit (PDU) by multiplexing at least one higher layer PDU within a maximum supported MAC PDU size;

selecting a TFC for the MAC PDU from the allowed TFCS subset;

performing a padding to the MAC PDU so that the MAC PDU fits into the selected TFC;

allocating radio resources and parameters for an initial transmission of the MAC PDU; and

retransmitting the MAC PDU when the initial transmission of the MAC PDU fails, the retransmission being performed by using the same radio resources and parameters used for the initial transmission of the MAC PDU.

2. The method of claim 1 wherein the allowed TFCS subset is generated by eliminating any TFC whose required number of subcarrier blocks exceeds an allocated number of subcarrier blocks.

3. The method of claim 1 further comprising:

performing at least one of expanding the allowed TFCS subset and reducing the allowed TFCS subset based on data received from a base station.

4. The method of claim 1 wherein the same TFC used for the initial transmission is used for retransmission of the MAC PDU.

5. The method of claim 1 wherein a new TFC is selected for the retransmission of the MAC PDU.

6. The method of claim 1 wherein the MAC PDU is fragmented into multiple fragmented PDUs for retransmission, whereby each fragmented PDU is retransmitted separately.

7. The method of claim 6 wherein an overhead for fragmentation is considered for the maximum supported MAC PDU size.

8. The method of claim 6 wherein the same TFC used for the initial transmission of the MAC PDU is used for first retransmission of the fragmented PDUs.

9. The method of claim 6 wherein a TFC with a lower MCS compared to the one used for initial transmission of the MAC PDU is used for first retransmission of the fragmented PDUs.

10. The method of claim 6 wherein only fragments acknowledged with a negative acknowledgement (NACK) are subsequently retransmitted.

11. The method of claim 10 wherein a TFC with a lower MCS compared to a highest allowable MCS is used for the fragments acknowledged with a NACK.

12. The method of claim 1 further comprising:

allocating new radio resources and parameters when the retransmission of the MAC PDU fails; and

selecting a new TFC for a second retransmission of the MAC PDU.

13. The method of claim 12 wherein the MAC PDU is fragmented into multiple fragmented PDUs, whereby each fragmented PDU is retransmitted separately.

14. The method of claim 13 wherein an overhead for fragmentation is considered for the maximum supported MAC PDU size.

15. The method of claim 14 wherein the same TFC used for initial transmission of the MAC PDU is used for the second retransmission of the fragmented PDUs.

16. The method of claim 14 wherein a TFC with a lower MCS compared to the one used for initial transmission of the MAC PDU is used for the second retransmission of the fragmented PDUs.

17. The method of claim 13 wherein only fragmented PDUs acknowledged with a negative acknowledgement (NACK) are subsequently retransmitted.

18. The method of claim 17 wherein a TFC with a lower MCS compared to a highest allowable MCS is used for the fragmented PDUs acknowledged with a NACK.

19. An apparatus for selecting a transport format combination (TFC) for wireless transmission of data, the apparatus comprising:

a TFC recovery and elimination unit configured to calculate a power requirement for each TFC in a transport format combination set (TFCS) based on the number of bits in each TFC and a modulation and coding scheme (MCS) used in each TFC, and generate an allowed TFCS subset by eliminating any TFC whose power requirement exceeds a power ceiling, and whose MCS exceeds a recommended MCS;

a multiplexing and transmission sequence number (TSN) setting unit configured to generate a medium access control (MAC) protocol data unit (PDU) by multiplexing at least one higher layer PDU within a maximum supported MAC PDU size; and

a TFC selection and padding unit configured to select a TFC for the MAC PDU from the allowed TFCS subset and perform a padding to the MAC PDU so that the MAC PDU fits into the selected TFC, wherein radio resources and parameters are allocated for an initial transmission of the MAC PDU, the MAC PDU is retransmitted when the initial transmission of the MAC PDU fails, the retransmission being performed by using the same radio resources and parameters used for the initial transmission of the MAC PDU.

20. The apparatus of claim 19 wherein the allowed TFCS subset is generated by eliminating any TFC whose required number of subcarrier blocks exceeds an allocated number of subcarrier blocks.

21. The apparatus of claim 19 wherein the TFC recovery and elimination unit is further configured to perform at least one of expand the allowed TFCS subset and reduce the allowed TFCS subset based on data received from a base station.

22. The apparatus of claim 19 wherein the same TFC used for the initial transmission is used for retransmission of the MAC PDU.

23. The apparatus of claim 19 wherein a new TFC is selected for the retransmission of the MAC PDU.

24. The apparatus of claim 19 wherein the MAC PDU is fragmented into multiple fragmented PDUs for retransmission, whereby each fragmented PDU is retransmitted separately.

25. The apparatus of claim 24 wherein the multiplexing and TSN setting unit considers an overhead for fragmentation for the maximum supported MAC PDU size.

26. The apparatus of claim 24 wherein the same TFC used for the initial transmission of the MAC PDU is used for first retransmission of the fragmented PDUs.

27. The apparatus of claim 24 wherein a TFC with a lower MCS compared to the one used for initial transmission of the MAC PDU is used for first retransmission of the fragmented PDUs.

28. The apparatus of claim 24 wherein only fragments acknowledged with a negative acknowledgement (NACK) are subsequently retransmitted.

29. The apparatus of claim 28 wherein a TFC with a lower MCS compared to a highest allowable MCS is used for the fragments acknowledged with a NACK.

30. The apparatus of claim 19 wherein the TFC recovery and elimination unit generates a new allowed TFCS subset based on new radio resources and parameters when the retransmission of the MAC PDU fails, whereby the MAC PDU is retransmitted by using the new allowed TFCS subset.

31. The apparatus of claim 30 wherein the MAC PDU is fragmented into multiple fragmented PDUs, whereby each fragmented PDU is retransmitted separately.

32. The apparatus of claim 31 wherein the multiplexing and TSN setting unit considers an overhead for fragmentation for the maximum supported MAC PDU size.

33. The apparatus of claim 32 wherein the same TFC used for initial transmission of the MAC PDU is used for a second retransmission of the fragmented PDUs.

34. The apparatus of claim 32 wherein a TFC with a lower MCS compared to the one used for initial transmission of the MAC PDU is used for a second retransmission of the fragmented PDUs.

35. The apparatus of claim 31 wherein only fragmented PDUs acknowledged with a negative acknowledgement (NACK) are subsequently retransmitted.

36. The apparatus of claim 35 wherein a TFC with a lower MCS compared to a highest allowable MCS is used for the fragmented PDUs acknowledged with a NACK.