Communication signal decoding with iterative cooperation between inner and outer codes

• US 8,640,012 B2
• Filed: 04/27/2009
• Issued: 01/28/2014
• Est. Priority Date: 04/28/2008
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ling, Fuyun, Sun, Thomas, Tian, Tao, Krishnamoorthi, Raghuraman, Jiang, Jing
• Primary Examiner(s): LE, DIEU MINH T
• Application Number:
  US12/430,719
• Publication Number:
  US 20090271688A1
• Time in Patent Office: 1,737 Days
• Field of Search: 714/784, 714785-788, 714/791
• US Class Current: 714/784
• CPC Class Codes: H03M 13/1111 Soft-decision decoding, e.g. by means of message passing or belief propagation algorithms
• CPC Class Codes: H03M 13/1117 using approximations for check node processing, e.g. an outgoing message is depending on the signs and the minimum over the magnitudes of all incoming messages according to the min-sum rule
• CPC Class Codes: H03M 13/112 with correction functions for the min-sum rule, e.g. using an offset or a scaling factor
• CPC Class Codes: H03M 13/1191 Codes on graphs other than LDPC codes
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/152 Bose-Chaudhuri-Hocquenghem [BCH] codes
• CPC Class Codes: H03M 13/19 Single error correction without using particular properties of the cyclic codes, e.g. Hamming codes, extended or generalised Hamming codes
• CPC Class Codes: H03M 13/23 using convolutional codes, e.g. unit memory codes
• CPC Class Codes: H03M 13/2966 Turbo codes concatenated with another code, e.g. an outer block code
• CPC Class Codes: H03M 13/658 Scaling by multiplication or division
• CPC Class Codes: H04L 1/005 Iterative decoding, including iteration between signal detection and decoding operation
• CPC Class Codes: H04L 1/0064 Concatenated codes

Abstract

Received communication signals may be decoded according to a combined, iterative inner code—outer code decoding technique. The inner code decoding is based on information produced by the outer code decoding.

Claims

1. An apparatus for processing data signals transmitted on a communication link, comprising:

an input for receiving the data signals including systematic log likelihood ratios (LLRs);

a turbo decoder coupled to said input and configured to perform turbo decoding;

a Reed-Solomon (RS) decoder coupled to said turbo decoder and configured to perform RS decoding;

wherein said turbo decoding is based on RS decoding information produced by said RS decoding;

a first summing element for receiving first extrinsic LLRs from a first maximum of a first decoder in the turbo decoder and deinterleaved second extrinsic LLRs from a second decoder in the turbo decoder, wherein an input to the RS decoder includes a result obtained by subtracting an output of the RS decoder from an output of the first summing element; and

a second summing element for receiving a first input and the systematic LLRs and providing an output to the first decoder, wherein the first input includes the output of the RS decoder.

2. The apparatus of claim 1, wherein said RS decoding information includes extrinsic information produced by said RS decoding.

3. The apparatus of claim 2, wherein said RS decoding is based on extrinsic information produced by said turbo decoding.

4. The apparatus of claim 1, wherein said RS decoding is based on extrinsic information produced by said turbo decoding.

5. The apparatus of claim 1, wherein said RS decoder is a soft input-soft output (SISO) decoder.

6. The apparatus of claim 1, including a belief propagation updating link coupled between said turbo decoder and said RS decoder, and configured to apply belief propagation to one of extrinsic information produced by said RS decoding and extrinsic information produced by said turbo decoding.

7. The apparatus of claim 6, including a further belief propagation updating link coupled between said turbo decoder and said RS decoder, and configured to apply belief propagation to the other of said extrinsic information produced by said RS decoding and said extrinsic information produced by said turbo decoding.

8. The apparatus of claim 1, including a belief accumulation updating link coupled between said turbo decoder and said RS decoder, and configured to apply belief accumulation to one of extrinsic information produced by said RS decoding and extrinsic information produced by said turbo decoding.

9. The apparatus of claim 8, including a belief propagation updating rule link between said turbo decoder and said RS decoder, and configured to apply belief propagation to the other of said extrinsic information produced by said RS decoding and said extrinsic information produced by said turbo decoding.

10. The apparatus of claim 1, wherein said RS decoding implements one of belief propagation decoding and belief accumulation decoding at the variable node for RS SISO decoding.

11. The apparatus of claim 1, wherein said RS decoding implements a min sum algorithm at the check node for RS SISO decoding.

12. The apparatus of claim 1, wherein the communication link is a wireless communication link.

13. A method of processing data signals transmitted on a communication link, comprising:

receiving the data signals including systematic log likelihood ratios (LLRs); and

performing turbo decoding on the data signals;

performing RS decoding, wherein said turbo decoding is based on RS decoding information produced by said RS decoding; and

summing first extrinsic LLRs from a first maximum a first decoding process in the turbo decoding and deinterleaved second extrinsic LLRs from a second decoding process in the turbo decoding to obtain a first summing result, and providing to the RS decoding a result obtained by subtracting an output of the RS decoding from the first summing result; and

summing a first input and the systematic LLRs to obtain a second summing result and providing the second summing result to the first decoding process, wherein the first input includes the output of the RS decoding.

14. The method of claim 13, wherein said RS decoding information includes extrinsic information produced by said RS decoding.

15. The method of claim 14, wherein said RS decoding is based on extrinsic information produced by said turbo decoding.

16. The method of claim 13, wherein said RS decoding is based on extrinsic information produced by said turbo decoding.

17. The method of claim 13, including applying belief propagation to one of extrinsic information produced by said RS decoding and extrinsic information produced by said turbo decoding, and using a result of said belief propagation to produce the other of said extrinsic information.

18. The method of claim 17, including applying further belief propagation to the other of said extrinsic information, and using a result of said further belief propagation to produce said one of said extrinsic information.

19. The method of claim 13, including applying belief accumulation to one of extrinsic information produced by said RS decoding and extrinsic information produced by said turbo decoding, and using a result of said belief accumulation to produce the other of said extrinsic information.

20. The method of claim 19, including applying belief propagation to the other of said extrinsic information, and using a result of said belief propagation decoding to produce said one of said extrinsic information.

21. The method of claim 13, wherein said RS decoding includes RS SISO decoding.

22. The method of claim 13, wherein said RS decoding implements one of belief propagation decoding and belief accumulation decoding at the variable node for RS SISO decoding.

23. The method of claim 13, wherein said RS decoding implements a min sum algorithm at the check node for RS SISO decoding.

24. The method of claim 13, wherein the communication link is a wireless communication link.

25. An apparatus for processing data signals transmitted on a communication link, comprising:

means for receiving the data signals including systematic log likelihood ratios (LLRs); and

means for performing turbo decoding on the data signals;

means for performing RS decoding, wherein said turbo decoding is based on RS decoding information produced by said RS decoding;

means for summing first extrinsic LLRs from a first maximum a first decoding process in the turbo decoding and deinterleaved second extrinsic LLRs from a second decoding process in the turbo decoding to obtain a first summing result, and providing to the RS decoding a result obtained by subtracting an output of the RS decoding from the first summing result; and

means for summing a first input and the systematic LLRs to obtain a second summing result and providing the second summing result to the first decoding process, wherein the first input includes the output of the RS decoding.

26. The apparatus of claim 25, wherein said RS decoding information includes extrinsic information produced by said means for performing RS decoding.

27. The apparatus of claim 26, wherein said RS decoding is based on extrinsic information produced by said means for performing turbo decoding.

28. The apparatus of claim 25, wherein said RS decoding is based on extrinsic information produced by said means for performing turbo decoding.

29. The apparatus of claim 25, wherein said means for performing RS decoding is a means for performing soft input-soft output (SISO) decoding.

30. The apparatus of claim 25, including a means for updating belief propagation coupled between said means for performing turbo decoding and said means for performing RS decoding, and configured to apply belief propagation to one of extrinsic information produced by said RS decoding and extrinsic information produced by said turbo decoding.

31. The apparatus of claim 30, including a further means for updating belief propagation coupled between said means for performing turbo decoding and said means for performing RS decoding, and configured to apply belief propagation to the other of said extrinsic information produced by said RS decoding and said extrinsic information produced by said turbo decoding.

32. The apparatus of claim 25, including a means for updating belief accumulation coupled between said means for performing turbo decoding and said means for performing RS decoding, and configured to apply belief accumulation to one of extrinsic information produced by said RS decoding and extrinsic information produced by said turbo decoding.

33. The apparatus of claim 32, including a further means for updating belief propagation between said means for performing turbo decoding and said means for performing RS decoding, and configured to apply belief propagation to the other of said extrinsic information produced by said RS decoding and said extrinsic information produced by said turbo decoding.

34. The apparatus of claim 25, wherein said means for performing RS decoding implements one of belief propagation decoding and belief accumulation decoding at the variable node for RS SISO decoding.

35. The apparatus of claim 25, wherein said means for performing RS decoding implements a min sum algorithm at the check node for RS SISO decoding.

36. The apparatus of claim 25, wherein the communication link is a wireless communication link.

37. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing the at least one data processor to receive at least systematic log likelihood ratios (LLRs);

code for causing at least one data processor to perform turbo decoding;

code for causing the at least one data processor to perform RS decoding;

code for causing the at least one data processor to use said turbo decoding and said RS decoding in combination to decode data signals received via a communication link,

wherein said turbo decoding is based on RS decoding information produced by said RS decoding;

code for causing the at least one data processor to sum first extrinsic LLRs from a first maximum from a first decoding process in the turbo decoding and deinterleaved second extrinsic LLRs from a second decoding process in the turbo decoding to obtain a first summing result, and providing to the RS decoding a result obtained by subtracting an output of the RS decoding from the first summing result; and

code for causing the at least one data processor to sum a first input and the systematic LLRs to obtain a second summing result and providing the second summing result to the first decoding process, wherein the first input includes the output of the RS decoding.

38. The computer program product of claim 37, wherein said RS decoding information includes extrinsic information produced by said RS decoding.

39. The computer program product of claim 38, wherein said RS decoding is based on extrinsic information produced by said turbo decoding.

40. The computer program product of claim 37, wherein said RS decoding is based on extrinsic information produced by said turbo decoding.

41. The computer program product of claim 37, wherein said code for causing the at least one data processor to perform RS decoding is code for causing the at least one data processor to perform soft input-soft output (SISO) decoding.

42. The computer program product of claim 37, including code for causing the at least one data processor to apply belief propagation to one of extrinsic information produced by said RS decoding and extrinsic information produced by said turbo decoding.

43. The computer program product of claim 42, including code for causing the at least one data processor to apply belief propagation to the other of said extrinsic information produced by said RS decoding and said extrinsic information produced by said turbo decoding.

44. The computer program product of claim 37, including code for causing the at least one data processor to apply belief accumulation to one of extrinsic information produced by said RS decoding and extrinsic information produced by said turbo decoding.

45. The computer program product of claim 44, including code for causing the at least one data processor to apply belief propagation to the other of said extrinsic information produced by said RS decoding and said extrinsic information produced by said turbo decoding.

46. The computer program product of claim 37, wherein said RS decoding implements one of belief propagation decoding and belief accumulation decoding at the variable node for RS SISO decoding.

47. The computer program product of claim 37, wherein said RS decoding implements a min sum algorithm at the check node for RS SISO decoding.

48. The computer program product of claim 37, wherein the communication link is a wireless communication link.

49. An apparatus for processing data signals transmitted on a communication link, comprising:

an input for receiving the data signals including systematic log likelihood ratios (LLRs);

an inner decoder coupled to said input and configured to perform inner decoding;

an outer decoder coupled to said inner decoder and configured to perform outer decoding,

wherein said inner decoding is based on outer decoding information produced by said outer decoding;

a first summing element for receiving first extrinsic LLRs from a first maximum a first decoder in the turbo decoder and deinterleaved second extrinsic LLRs from a second decoder in the inner decoder, wherein an input to the outer decoder includes a result obtained by subtracting an output of the outer decoder from an output of the first summing element; and

a second summing element for receiving a first input and the systematic LLRs and providing an output to the first decoder, wherein the first input includes the output of the outer decoder.

50. The apparatus of claim 49, wherein said inner decoding includes one of convolutional decoding and LDPC decoding, and said outer decoding includes one of BCH decoding and Hamming decoding.

51. The apparatus of claim 49, wherein said communication link includes a data storage system.

52. A method of processing data signals transmitted on a communication link, comprising:

receiving the data signals including systematic log likelihood ratios (LLRs);

decoding the data signals, including performing inner decoding and performing outer decoding,

wherein said inner decoding is based on outer decoding information produced by said outer decoding;

summing first extrinsic LLRs from a first maximum a first decoding process in the inner decoding and deinterleaved second extrinsic LLRs from a second decoding process in the inner decoding to obtain a first summing result, and providing to the outer decoding a result obtained by subtracting an output of the outer decoding from the first summing result; and

summing a first input and the systematic LLRs to obtain a second summing result and providing the second summing result to the first decoding process, wherein the first input includes the output of the outer decoding.

53. The method of claim 52, wherein said inner decoding includes one of convolutional decoding and LDPC decoding, and said outer decoding includes one of BCH decoding and Hamming decoding.

54. The method of claim 52, wherein said communication link includes a data storage system.

55. An apparatus for processing data signals transmitted on a communication link, comprising:

means for receiving the data signals including systematic log likelihood ratios (LLRs);

means for decoding the data signals, including means for performing inner decoding and means for performing outer decoding,

wherein said inner decoding is based on outer decoding information produced by said outer decoding;

means for summing first extrinsic LLRs from a first maximum a first decoding process in the inner decoding and deinterleaved second extrinsic LLRs from a second decoding process in the inner decoding to obtain a first summing result, and providing to the outer decoding a result obtained by subtracting an output of the outer decoding from the first summing result; and

means for summing a first input and the systematic LLRs to obtain a second summing result and providing the second summing result to the first decoding process, wherein the first input includes the output of the outer decoding.

56. The apparatus of claim 55, wherein said means for performing inner decoding includes one of means for performing convolutional decoding and means for performing LDPC decoding, and said means for performing outer decoding includes one of means for performing BCH decoding and means for performing Hamming decoding.

57. The apparatus of claim 55, wherein said communication link includes means for data storage.

58. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing at least one data processor to receive at least systematic log likelihood ratios (LLRs);

code for causing at least one data processor to perform outer decoding;

code for causing the at least one data processor to perform inner decoding;

code for causing the at least one data processor to use said inner decoding and said outer decoding in combination to decode data signals received via a communication link,

wherein said inner decoding is based on outer decoding information produced by said outer decoding;

code for causing the at least one data processor to sum first extrinsic LLRs from a first maximum from a first decoding process in the inner decoding and deinterleaved second extrinsic LLRs from a second decoding process in the inner decoding to obtain a first summing result, and providing to the outer decoding a result obtained by subtracting an output of the outer decoding from the first summing result; and

code for causing the at least one data processor to sum a first input and the systematic LLRs to obtain a second summing result and providing the second summing result to the first decoding process, wherein the first input includes the output of the outer decoding.

59. The computer program product of claim 58, wherein said inner decoding includes one of convolutional decoding and LDPC decoding, and said outer decoding includes one of BCH decoding and Hamming decoding.

60. The computer program product of claim 58, wherein said communication link includes a data storage system.