Serial concatenation of interleaved convolutional codes forming turbo-like codes

• US 7,916,781 B2
• Filed: 06/30/2008
• Issued: 03/29/2011
• Est. Priority Date: 05/18/2000
• Status: Expired due to Fees
• 

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Jin, Hui, Khandekar, Aamod, McEliece, Robert J.
• Primary Examiner(s): Ha, Dac V
• Application Number:
  US12/165,606
• Publication Number:
  US 20080294964A1
• Time in Patent Office: 1,002 Days
• Field of Search: 375/240, 375/240.24, 375/254, 375/285, 375/295, 375/296, 375/260, 714/755, 714/758, 714/800, 714/801, 714/804, 714/805
• US Class Current: 375/240
• CPC Class Codes: H03M 13/1102 Codes on graphs and decoding on graphs, e.g. low-density parity check [LDPC] codes
• CPC Class Codes: H03M 13/1197 Irregular repeat-accumulate [IRA] codes
• CPC Class Codes: H03M 13/2939 using convolutional codes H03M13/2957 takes precedence
• CPC Class Codes: H03M 13/2972 Serial concatenation using convolutional component codes

Abstract

A serial concatenated coder includes an outer coder and an inner coder. The outer coder irregularly repeats bits in a data block according to a degree profile and scrambles the repeated bits. The scrambled and repeated bits are input to an inner coder, which has a rate substantially close to one.

Claims

1. A method of encoding a signal, comprising:

receiving a block of data in the signal to be encoded, the block of data including information bits;

performing a first encoding operation on at least some of the information bits, the first encoding operation being a linear transform operation that generates L transformed bits; and

performing a second encoding operation using the L transformed bits as an input, the second encoding operation including an accumulation operation in which the L transformed bits generated by the first encoding operation are accumulated, said second encoding operation producing at least a portion of a codeword, wherein L is two or more.

2. The method of claim 1, further comprising:

outputting the codeword, wherein the codeword comprises parity bits.

3. The method of claim 2, wherein outputting the codeword comprises:

outputting the parity bits; and

outputting at least some of the information bits.

4. The method of claim 3, wherein outputting the codeword comprises:

outputting the parity bits following the information bits.

5. The method of claim 2, wherein performing the first encoding operation comprises transforming the at least some of the information bits via a low density generator matrix transformation.

6. The method of claim 5, wherein generating each of the L transformed bits comprises mod-2 or exclusive-OR summing of bits in a subset of the information bits.

7. The method of claim 6, wherein each of the subsets of the information bits includes a same number of the information bits.

8. The method of claim 6, wherein at least two of the information bits appear in three subsets of the information bits.

9. The method of claim 6, wherein the information bits appear in a variable number of subsets.

10. The method of claim 2, wherein performing the second encoding operation comprises using a first of the parity bits in the accumulation operation to produce a second of the parity bits.

11. The method of claim 10, wherein outputting the codeword comprises outputting the second of the parity bits immediately following the first of the parity bits.

12. The method of claim 2, wherein performing the second encoding operation comprises performing one of a mod-2 addition and an exclusive-OR operation.

13. A method of encoding a signal, comprising:

receiving a block of data in the signal to be encoded, the block of data including information bits; and

performing an encoding operation using the information bits as an input, the encoding operation including an accumulation of mod-2 or exclusive-OR sums of bits in subsets of the information bits, the encoding operation generating at least a portion of a codeword,

wherein the information bits appear in a variable number of subsets.

14. The method of claim 13, further comprising:

outputting the codeword, wherein the codeword comprises parity bits.

15. The method of claim 14, wherein outputting the codeword comprises:

outputting the parity bits; and

outputting at least some of the information bits.

16. The method of claim 15, wherein the parity bits follow the information bits in the codeword.

17. The method of claim 13, wherein each of the subsets of the information bits includes a constant number of the information bits.

18. The method of claim 13, wherein performing the encoding operation further comprises:

performing one of the mod-2 addition and the exclusive-OR summing of the bits in the subsets.

19. A method of encoding a signal, comprising:

receiving a block of data in the signal to be encoded, the block of data including information bits; and

performing an encoding operation using the information bits as an input, the encoding operation including an accumulation of mod-2 or exclusive-OR sums of bits in subsets of the information bits, the encoding operation generating at least a portion of a codeword, wherein at least two of the information bits appear in three subsets of the information bits.

20. A method of encoding a signal, comprising:

receiving a block of data in the signal to be encoded, the block of data including information bits; and

performing an encoding operation using the information bits as an input, the encoding operation including an accumulation of mod-2 or exclusive-OR sums of bits in subsets of the information bits, the encoding operation generating at least a portion of a codeword, wherein performing the encoding operation comprises;

mod-2 or exclusive-OR adding a first subset of information bits in the collection to yield a first sum;

mod-2 or exclusive-OR adding a second subset of information bits in the collection and the first sum to yield a second sum.

21. A method comprising:

receiving a collection of information bits;

mod-2 or exclusive-OR adding a first subset of information bits in the collection to yield a first parity bit;

mod-2 or exclusive-OR adding a second subset of information bits in the collection and the first parity bit to yield a second parity bit; and

outputting a codeword that includes the first parity bit and the second parity bit.

22. The method of claim 21, wherein:

the method further comprises mod-2 or exclusive-OR adding additional subsets of information bits in the collection and parity bits to yield additional parity bits; and

the information bits in the collection appear in a variable number of subsets.