Methods and apparatus for conditional offload of one or more log-likelihood ratios (LLRs) or decoded bits

• US 9,204,437 B2
• Filed: 02/21/2014
• Issued: 12/01/2015
• Est. Priority Date: 02/27/2013
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Smee, John Edward, McCloud, Michael Lee, Black, Peter John, Gorokhov, Alexei Yurievitch, Tran, Jean-Marie Quoc Danh
• Primary Examiner(s): HAN, CLEMENCE S
• Application Number:
  US14/186,953
• Publication Number:
  US 20140241269A1
• Time in Patent Office: 648 Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 1/1835 Buffer management
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

Techniques and apparatus are provided for conditional offload of one or more LLRs or decoded bits. An exemplary electronic device (ED) method includes receiving a transmission of a physical downlink shared channel (PDSCH) having a transport block (TB) comprising at least one code block (CB), performing a cyclic redundancy check (CRC) of the at least one CB, in a memory external to a modem core of the ED, storing a subset of log-likelihood ratios (LLRs) associated with the at least one CB if the at least one CB failed the CRC or decoded bits associated with the at least one CB if the at least one CB passed the CRC, wherein the subset is based on an LLR range of the transmission relative to an LLR range of one or more previous transmissions, and using the stored subset of LLRs or decoded bits to process a re-transmission of the PDSCH.

Claims

1. A method of wireless communications by an electronic device, comprising:

receiving a transmission of a physical downlink shared channel (PDSCH) having a transport block (TB) comprising at least one code block (CB);

performing a cyclic redundancy check (CRC) of the at least one CB;

in a memory external to a modem core of the electronic device, storing a subset of log-likelihood ratios (LLRs) associated with the at least one CB if the at least one CB failed the CRC or decoded bits associated with the at least one CB if the at least one CB passed the CRC, wherein the subset is based on an LLR range of the transmission relative to an LLR range of one or more previous transmissions; and

using the stored subset of LLRs or decoded bits to process a re-transmission of the PDSCH.

2. The method of claim 1, further comprising:

performing a CRC of the TB.

3. The method of claim 2, further comprising:

storing LLRs for all CBs of the TB only if the CRC of the TB fails.

4. The method of claim 1, wherein the TB comprises at least two CBs.

5. The method of claim 1, wherein the subset comprises LLRs outside the LLR range of the one or more previous transmissions.

6. The method of claim 1, wherein the subset is further based on a size of memory local to the modem core.

7. The method of claim 1, wherein the TB comprises at least two CBs, and further comprising:

forming TB bits based on CB bits that were decoded and stored in the memory on a previous transmission and CB bits that were decoded successfully on the re-transmission.

8. The method of claim 7, further comprising:

performing a CRC on a TB of the re-transmission to verify correctness of CB bits that were decoded on the previous transmission and CB bits that were decoded on the re-transmission.

9. The method of claim 1, further comprising:

in the memory, storing based at least in part on an LLR range of the re-transmission, LLRs associated with the re-transmission including the at least one CB if the at least one CB failed the CRC or decoded bits associated with the re-transmission including the at least one CB if the at least one CB passed the CRC.

10. The method of claim 9, further comprising:

in the memory, storing based on LLR ranges of previous transmissions, LLRs associated with a second re-transmission including the at least one CB if the at least one CB failed the CRC or decoded bits associated with the second re-transmission including the at least one CB if the at least one CB passed the CRC.

11. The method of claim 1, wherein the LLRs or decoded bits are stored in a memory local to the modem core prior to storing in the memory.

12. The method of claim 1, wherein using the stored subset of LLRs or decoded bits to process a re-transmission includes reading the stored LLRs or decoded bits from the memory.

13. An apparatus for wireless communications by an electronic device, comprising:

means for receiving a transmission of a physical downlink shared channel (PDSCH) having a transport block (TB) comprising at least one code block (CB);

means for performing a cyclic redundancy check (CRC) of the at least one CB;

means for, in a memory external to a modem core of the electronic device, storing a subset of log-likelihood ratios (LLRs) associated with the at least one CB if the at least one CB failed the CRC or decoded bits associated with the at least one CB if the at least one CB passed the CRC, wherein the subset is based on an LLR range of the transmission relative to an LLR range of one or more previous transmissions; and

means for using the stored subset of LLRs or decoded bits to process a re-transmission of the PDSCH.

14. The apparatus of claim 13, further comprising:

means for performing a CRC of the TB.

15. The apparatus of claim 14, further comprising:

means for storing LLRs for all CBs of the TB only if the CRC of the TB fails.

16. The apparatus of claim 13, wherein the TB comprises at least two CBs.

17. The apparatus of claim 13, wherein the subset comprises LLRs outside the LLR range of the one or more previous transmissions.

18. The apparatus of claim 13, wherein the subset is further based on a size of memory local to the modem core.

19. The apparatus of claim 13, wherein the TB comprises at least two CBs, and further comprising:

means for forming TB bits based on CB bits that were decoded and stored in the memory on a previous transmission and CB bits that were decoded successfully on the re-transmission.

20. The apparatus of claim 19, further comprising:

means for performing a CRC on a TB of the re-transmission to verify correctness of CB bits that were decoded on the previous transmission and CB bits that were decoded on the re-transmission.

21. The apparatus of claim 13, further comprising:

means for, in the memory, storing based at least in part on an LLR range of the re-transmission, LLRs associated with the re-transmission including the at least one CB if the at least one CB failed the CRC or decoded bits associated with the re-transmission including the at least one CB if the at least one CB passed the CRC.

22. The apparatus of claim 21, further comprising:

means for, in the memory, storing based on LLR ranges of previous transmissions, LLRs associated with a second re-transmission including the at least one CB if the at least one CB failed the CRC or decoded bits associated with the second re-transmission including the at least one CB if the at least one CB passed the CRC.

23. The apparatus of claim 13, wherein the LLRs or decoded bits are stored in a memory local to the modem core prior to storing in the memory.

24. The apparatus of claim 13, wherein using the stored subset of LLRs or decoded bits to process a re-transmission includes reading the stored LLRs or decoded bits from the memory.

25. An apparatus for wireless communications by an electronic device, comprising:

at least one processor configured to;

receive a transmission of a physical downlink shared channel (PDSCH) having a transport block (TB) comprising at least one code block (CB);

perform a cyclic redundancy check (CRC) of the at least one CB;

in a memory external to a modem core of the electronic device, store a subset of log-likelihood ratios (LLRs) associated with the at least one CB if the at least one CB failed the CRC or decoded bits associated with the at least one CB if the at least one CB passed the CRC, wherein the subset is based on an LLR range of the transmission relative to an LLR range of one or more previous transmissions; and

use the stored subset of LLRs or decoded bits to process a re-transmission of the PDSCH; and

a memory coupled with the at least one processor.

26. The apparatus of claim 25, further comprising:

means for, in the memory, storing based at least in part on a LLR range of the re-transmission, LLRs associated with the re-transmission including the at least one CB if the at least one CB failed the CRC or decoded bits associated with the re-transmission including the at least one CB if the at least one CB passed the CRC.

27. The apparatus of claim 26, further comprising:

means for, in the memory, storing based on LLR ranges of previous transmissions, LLRs associated with a second re-transmission including the at least one CB if the at least one CB failed the CRC or decoded bits associated with the second re-transmission including the at least one CB if the at least one CB passed the CRC.

28. A non-transitory computer-readable medium having instructions stored thereon, the instructions executable by an apparatus for:

receiving a transmission of a physical downlink shared channel (PDSCH) having a transport block (TB) comprising at least one code block (CB);

performing a cyclic redundancy check (CRC) of the at least one CB;

in a memory external to a modem core of the electronic device, storing a subset of log-likelihood ratios (LLRs) associated with the at least one CB if the at least one CB failed the CRC or decoded bits associated with the at least one CB if the at least one CB passed the CRC, wherein the subset is based on an LLR range of the transmission relative to an LLR range of one or more previous transmissions; and

using the stored subset of LLRs or decoded bits to process a re-transmission of the PDSCH.

29. The computer-readable medium of claim 28, the instructions further executable by an apparatus for:

in the memory, storing based at least in part on a LLR range of the re-transmission, LLRs associated with the re-transmission including the at least one CB if the at least one CB failed the CRC or decoded bits associated with the re-transmission including the at least one CB if the at least one CB passed the CRC.

30. The computer-readable medium of claim 29, the instructions further executable by an apparatus for:

in the memory, storing based on LLR ranges of previous transmissions, LLRs associated with a second re-transmission including the at least one CB if the at least one CB failed the CRC or decoded bits associated with the second re-transmission including the at least one CB if the at least one CB passed the CRC.