Quasi error free (QEF) communication using turbo codes

• US 7,421,044 B2
• Filed: 09/05/2001
• Issued: 09/02/2008
• Est. Priority Date: 09/05/2000
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Jones, Christopher R., Cameron, Kelly B.
• Primary Examiner(s): Ghayour; Mohammad
• Assistant Examiner(s): Torres; Juan A
• Application Number:
  US09/947,414
• Publication Number:
  US 20020051499A1
• Time in Patent Office: 2,554 Days
• Field of Search: 375/222, 714/756
• US Class Current: 375/340
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/256 with trellis coding, e.g. with convolutional codes and TCM
• CPC Class Codes: H03M 13/258 with turbo codes, e.g. Turbo Trellis Coded Modulation [TTCM]
• CPC Class Codes: H03M 13/2732 Convolutional interleaver; Interleavers using shift-registers or delay lines like, e.g. Ramsey type interleaver
• CPC Class Codes: H03M 13/275 Interleaver wherein the permutation pattern is obtained using a congruential operation of the type y=ax+b modulo c
• CPC Class Codes: H03M 13/2789 Interleaver providing variable interleaving, e.g. variable block sizes
• CPC Class Codes: H03M 13/29 combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes
• CPC Class Codes: H03M 13/2945 using at least three error correction codes H03M13/2957 takes precedence
• CPC Class Codes: H03M 13/2966 Turbo codes concatenated with another code, e.g. an outer block code
• CPC Class Codes: H03M 13/3988 for rate k/n convolutional codes, with k>1, obtained by convolutional encoders with k inputs and n outputs
• CPC Class Codes: H03M 13/45 Soft decoding, i.e. using symbol reliability information H03M13/41 takes precedence
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/0066 Parallel concatenated codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27

Abstract

Quasi error free method and system are presented for encoding and decoding information using turbo codes as an inner code in conjunction with an algebraic outer code linked by an interleaver. This combination of outer algebraic code and turbo inner code linked by an interleaver, which has a guaranteed minimum Depth between symbols output from the interleaver, can produce a quasi error free performance in systems utilizing Turbo-Codes without an increase in bandwidth.

Claims

1. A method for encoding data for correction of burst errors with a predetermined length, the method comprising:

algebraically encoding the data for producing algebraically encoded data;

determining a guaranteed depth for an interleaver to guarantee that the burst errors with the predetermined length are repaired, the guaranteed depth corresponding to the predetermined length of the burst errors and a depth of separation of input symbols;

performing interleaving of the algebraic encoded data in the interleaver having the guaranteed depth for producing interleaved data;

turbo encoding the interleaved data for producing turbo encoded data;

mapping a first symbol of the turbo encoded data to a first constellation having a corresponding first mapping;

mapping a second symbol of uncoded data, that has bypassed the turbo encoding, to a second constellation having a corresponding second mapping; and

mapping a third symbol of uncoded data, that includes at least one bit that has undergone interleaving using an interleaving employed in accordance with the turbo encoding, to the second constellation having the corresponding second mapping.

2. The method of claim 1 wherein algebraically encoding the data comprises Reed-Solomon encoding the data.

3. The method of claim 1 wherein interleaving the algebraic encoded data comprises using a Ramsey interleaver to interleave the algebraic encoded data.

4. The method of claim 1 wherein turbo encoding the interleaved data comprises modulo-N turbo encoding of the interleaved data.

5. The method of claim 4 wherein N>

2.

6. The method of claim 1 wherein turbo encoding the interleaved data further comprises providing at least one nonsystematic component encoding.

7. The method of claim 1 wherein the guaranteed depth is at least 201.

8. A method for decoding quasi error free encoded data the method comprising:

accepting data to be decoded which has been encoded according to the method of claim 1;

turbo decoding the data;

deinterleaving the turbo decoded data, after the turbo decoding is completed, using a deinterleaver having a guaranteed depth to produce deinterleaved data; and

algebraically decoding the deinterleaved data to produce decoded data.

9. The method of claim 8 wherein algebraically decoding the deinterleaved data comprises Reed-Solomon decoding the deinterleaved data.

10. The method of claim 8 wherein deinterleaving the data to be decoded comprises using a Ramsey deinterleaver to deinterleave the algebraic encoded data.

11. The method of claim 8 wherein turbo decoding the interleaved data comprises modulo-N turbo decoding of the interleaved data.

12. The method of claim 8 wherein N>

2.

13. The method of claim 11 wherein modulo-N turbo decoding further comprises parallel map decoding.

14. The method of claim 11 wherein the modulo-N turbo decoder is a parallel map decoder.

15. A decoder apparatus comprising:

a turbo decoder that accepts data to be decoded, which has been encoded according to the method of claim 1, to produce turbo decoded data;

a deinterleaver that accepts the turbo decoded data and produce deinterleaved data; and

an algebraic decoder that decodes the deinterleaved data to produce decoded data.

16. The apparatus of claim 15 wherein the algebraic decoder comprises a Reed-Solomon decoder.

17. The apparatus of claim 15 wherein the deinterleaver comprises a Ramsey deinterleaver.

18. The apparatus of claim 15 wherein the turbo decoder comprises a modulo-N turbo decoder.

19. The apparatus of claim 18 wherein N>

2.

20. An encoding apparatus for correcting burst errors with a predetermined length comprising:

an input for accepting data;

an algebraic encoder for receiving the data and algebraically encoding the data for producing algebraically encoded data;

an interleaver for interleaving the algebraically encoded data, said interleaver having a guaranteed depth to guarantee that the burst errors with the predetermined length are repaired,

the guaranteed depth corresponding to said predetermined length of the burst errors and a depth of separation of input symbols, for producing interleaved data;

a turbo encoder for encoding the interleaved data for producing turbo encoded data; and

a mapper that is operable to;

map a first symbol of the turbo encoded data to a first constellation having a corresponding first mapping;

map a second symbol of uncoded data, that has bypassed turbo encoding within the turbo encoder, to a second constellation having a corresponding second mapping; and

map a third symbol of uncoded data, that includes at least one bit that has undergone interleaving using an interleaving employed in accordance with the turbo encoding of the turbo encoder, to the second constellation having the corresponding second mapping.

21. The apparatus of claim 20 wherein the algebraic encoder comprises a Reed-Solomon encoder.

22. The apparatus of claim 20 wherein the interleaver comprises a Ramsey interleaver.

23. The apparatus of claim 20 wherein the turbo encoder comprises a modulo-N turbo encoder.

24. The apparatus of claim 20 wherein N>

2.