Channel constrained code aware interleaver

• US 8,055,973 B2
• Filed: 06/05/2009
• Issued: 11/08/2011
• Est. Priority Date: 06/05/2009
• Status: Active Grant

• Current Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Inventors: Parthasarathy, Sivagnanam, Garani, Shayan Srinivasa, Hu, Xinde, Richardson, Nicholas J.
• Primary Examiner(s): KERVEROS, DEMETRIOS C
• Application Number:
  US12/479,652
• Publication Number:
  US 20100313083A1
• Time in Patent Office: 886 Days
• Field of Search: 714/702, 714/755
• US Class Current: 714/755
• CPC Class Codes: G11B 2020/10796 address data
• CPC Class Codes: G11B 2020/185 using an low density parity check [LDPC] code
• CPC Class Codes: H03M 13/27 using interleaving techniques

Abstract

An interleaver is constructed based on the joint constraints imposed in the channel and the code domains. A sequentially optimal algorithm is used for mapping bits in the inter-symbol interference (ISI) domain to the code domain by taking into account the ISI memory depth and the connectivity of the nodes within the parity check matrix. Primary design constraints are considered such as the parallelism factor so that the proposed system is hardware compliant in meeting high throughput requirements.

Claims

1. An interleaver comprising:

a first input path;

a second input path;

a multiplexer having a first input coupled to the first input path, a second input coupled to the second input path, a control input for receiving a control signal, and an output;

a memory having a write input coupled to the output of the multiplexer and a read output; and

a FIFO having a write input coupled to the output of the memory and a read output, wherein

the memory comprises a plurality of interleaved sub-word (ISW) chunks, wherein

the ISW chucks are mapped from de-interleaved sub-word (DSW) chunks, wherein

the DSW chunks each comprises bits that have information and parity bits chosen from a plurality of code memory chunks in such a way that a chunk of consecutive κ

bits is randomly chosen from each code memory chunk.

2. The interleaver of claim 1 wherein the first input path comprises a memory access interface coupled to a multiplexer and write mask block.

3. The interleaver of claim 1 wherein the multiplexer and write mask block is also coupled to the read output of the memory.

4. The interleaver of claim 1 wherein the first input path is coupled to a code memory.

5. The interleaver of claim 4 wherein the code memory is coupled to a de-multiplexer having an input for receiving serial data.

6. The interleaver of claim 5 wherein the de-multiplexer is coupled to first and second shift registers for providing sub-circulant addresses.

7. The interleaver of claim 1 wherein the second input path comprises a sequential address generator.

8. The interleaver of claim 1 wherein the memory comprises a first RAM bank and a second RAM bank.

9. The interleaver of claim 1 wherein the FIFO comprises a plurality of FIFO stages for providing interleaver addresses for write and read sides.

10. The interleaver of claim 1 further comprising a control block for receiving a mode control signal, and for controlling the memory and the FIFO.

11. The interleaver of claim 10 wherein the control block further receives signal as to which FIFO must be selected depending upon the de-interleaver or interleaver operation performed in the decoder or the encoder side.

12. The interleaver of claim 10 wherein the control block is coupled to an address count block for providing interleaver address count.

13. The interleaver of claim 1 further comprising a plurality of multiplexers between the memory and the FIFO for the purpose of sending data from the RAM to the appropriate FIFO.

14. An interleaver comprising:

an input section that can be configured for a first operating mode or a second operating mode;

a memory having an input coupled to the input section and an output; and

a FIFO having an input coupled to the memory and an output for providing the addresses and the end of interleaver sub word signal to the appropriate read/write side where the interleaving operations are needed, wherein

the memory comprises a plurality of interleaved sub-word (ISW) chunks, wherein

the ISW chucks are mapped from de-interleaved sub-word (DSW) chunks, wherein

the DSW chunks each comprises bits that have information and parity bits chosen from a plurality of code memory chunks in such a way that a chunk of consecutive κ

bits is randomly chosen from each code memory chunk.

15. The interleaver of claim 14 wherein the first operating mode comprises a fixed memory based operating mode where the addresses are generated algorithmically using code aware constraints along with bylane mapping rules.

16. The interleaver of claim 14 wherein the second operating mode is on-the-fly way for generating addresses in real time operating mode.

17. The interleaver of claim 14 wherein the input section comprises a multiplexer.

18. The interleaver of claim 14 wherein the input section is coupled to a code memory.

19. The interleaver of claim 14 further comprising a control block for receiving serial to parallel interface for feeding the addresses depending on the operating mode selected and for controlling the memory and the FIFO.

20. The interleaver of claim 19 wherein the control block is coupled to an address count block for providing starting and the ending addresses for the interleaver.

21. A method of code aware interleaving, comprising:

identifying parity locations and mapping parity bits in a de-interleaved sub-word (DSW) memory to an interleaved sub-word (ISW) memory;

identifying information indices within the ISW memory that are by-lane constrained;

identifying a set of indices in a ISW domain that satisfy code constraints according to equation