Turbo interleaving apparatus and method

• US 6,598,202 B1
• Filed: 05/19/2000
• Issued: 07/22/2003
• Est. Priority Date: 05/19/1999
• Status: Expired

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Min-Goo, Lee, Young-Hwan, Choi, Soon-Jae, Kim, Beong-Jo
• Primary Examiner(s): Ton, David
• Application Number:
  US09/575,084
• Time in Patent Office: 1,159 Days
• Field of Search: 714/702, 714/701, 714/786, 714/788, 714/787, 714/761, 714/759, 714/752, 711/109
• US Class Current: 714/786
• CPC Class Codes: G11B 2220/2562 DVDs [digital versatile discs]; Digital video discs; MMCDs; HDCDs
• CPC Class Codes: H03M 13/27 using interleaving techniques
• CPC Class Codes: H03M 13/271 Row-column interleaver with permutations, e.g. block interleaving with inter-row, inter-column, intra-row or intra-column permutations
• CPC Class Codes: H03M 13/2714 Turbo interleaver for 3rd generation partnership project [3GPP] universal mobile telecommunications systems [UMTS], e.g. as defined in technical specification TS 25.212
• CPC Class Codes: H03M 13/276 Interleaving address generation
• CPC Class Codes: H03M 13/2764 Circuits therefore
• CPC Class Codes: H03M 13/2771 Internal interleaver for turbo codes H03M13/2714 and H03M13/2725 take precedence
• CPC Class Codes: H03M 13/2957 Turbo codes and decoding

Abstract

A 2-dimensional interleaving method is disclosed. The method comprises dividing a frame of input information bits into a plurality of groups and sequentially storing the divided groups in a memory; permuting the information bits of the groups according to a given rule and shifting an information bit existing at the last position of the last group to a position preceding the last position; and selecting the groups according to a predetermined order, and selecting one of the information bits in the selected group.

Claims

1. A turbo encoder comprising:

a first encoder for encoding a frame of input information bits to generate first coded symbols;

an interleaver for receiving the information bits and interleaving the information bits position such that an information bit existing at the last position of the frame is shifted to a position preceding the last position for not generating Critical Information Sequence Pattern (CISP); and

a second encoder for encoding the interleaved information bits to generate second coded symbols.

2. The turbo encoder as claimed in claim 1, wherein the interleaver comprises:

a controller for writing the information bits sequentially in memory and dividing the information bits into R groups each having the C information bits;

permuting the address of the information bit written in a jth row (where, j=0,1,2, . . . , R−

1) to positions C_j(i) in the row in accordance with an algorithm given by

i) C(i)=[g0×

C(i−

1)] mod p, i=1,2, . . . , (p−

2) and C(0)=1

ii) C_j(i)=C([i×

p_j] mod (p−

1)),

j=0,1,2, . . . , (R−

1), i=0,1,2, . . . , (p−

1), C_j(p−

1)=0, and C_j(p)=p

iii) exchange C<sub>R−

1</sub>(p) with C<sub>R−

1</sub>(0)

where p (prime number) indicates a prime number which is closest to K/R, g0 (primitive root) indicates a predetermined number corresponding to p, and p_j indicates a primitive number set.

3. The turbo encoder as claimed in claim 2, wherein the interleaver comprises:

a memory for storing the information bit frame sequentially;

a randomizer for permuting the address of the stored informnation bits according as shifting the address of an informnation bit existing at the last position to a position preceding the last position in the last group.

4. The turbo encoder as claimed in claim 3, wherein the randomizer exchanges an information bit address existing at the last position of the last group with an information bit address existing at a first position of the last group.

5. A device for permuting information bit addresses of an input frame which have R groups each having C information bits in a prime interleaver (PIL) used as an internal interleaver for a turbo encoder, the device comprising:

a memory for storing the information bit frame sequentially;

a randomizer for permuting the addresses of the information bit and changing the address of an last information bit to a position preceding the position in the last group.

6. The device as claimed in claim 5, wherein the randomizer exchanges an information bit position existing at the last position of the last group with an information bit position existing at a first position of the last group.

7. A device for interleaving a frame of K information bits which have R groups each having C information bits in a PIL interleaver used as an internal interleaver for a turbo encoder, the device comprising:

a controller for writing input information bits of a frame in a memory sequentially and permuting the position of the information bits written in a jth row (where, j can be 0,1,2, . . . , or R−

1) to position C_j(i) in the row in accordance with an algorithm given by

i) permute a base sequence C(i)=[g0×

C(i−

1)] mod p, i=1,2, . . . , (p−

2) and C(0)=1

ii) perform row permutation C_j(i)=C([i×

p_j] mod (p−

1)), j=0,1,2, . . . , (R−

1), i=0,1,2, . . . , (p−

1), C_j(p−

1)=0, and C_j(p)=p

iii) exchange C<sub>R−

1</sub>(p) with C<sub>R−

1</sub>(0)

where p (prime number) indicates a prime number which is closest to K/R, g0 (primitive root) indicates a predetermined number corresponding to p, and p_j indicates a primitive number set.

8. A 2-dimensional interleaving method comprising the steps of:

storing a frame of K input information bits into a memory sequentially and dividing an information bits into R groups each having C information bits;

permuting the information bits addresses of the each group according to a given rule; and

changing an information bit address existing at the last position of the last group to a address preceding the last position.

9. A 2-dimensional interleaving method as claimed in claim 8, wherein the permuting,

determining a minimum prime number p which is closest to K/R, sequentially writing input sequences of information bits of a frame in a memory;

selecting a primitive root g0 corresponding to the minimum prime number p, and generating a base sequence C(i) for intra-row permuting the input sequences written in the rows in accordance with

10. The 2-dimensional interleaving method as claimed in claim 8, wherein an information bit address existing at the last position of the last group is exchanged with an information bit address existing at a first position of the last group.

11. A 2-dimensional interleaving method comprising the steps of:

writing input sequences of a frame of input information bits which have R groups each having C information bits in a memory;

permuting the address of the information bits written in memory according to a given rule;

shifting an address of an information bit written in the last position of the last group to a position preceding the last group.

12. The 2-dimensioinal interleaving method as claimed in claim 11, wherein the input sequence written in the last position of the last group is exchanged with an input sequence written in a first position of the last group.

13. A method for interleaving a frame of input information bits which have R groups each having C information bits in a PIL interleaver used as an internal interleaver for a turbo encoder, the method comprising the steps of:

a) permuting the information bits position of the groups according to predetermined PIL interleaving rule;

b) changing an information bit existing at the last position of the frame to a position preceding the last position.

14. The method as claimed in claim 13, wherein an information bit position existing at the last position of the last group is exchanged with an information bit existing at a first position of the last group.

15. The method as claimed in claim 13, wherein in the step a and b), the information bits position of the frame written in an jth row (where j=0,1,2, . . . , R−

1) are permuted to positions C_j(i) in the row in accordance with the steps of an algorithm given by the steps of

i) calculating C(i)=[g0×

c(i−

1)] mod p, i=1,2, . . . , (p−

2) and C(0)=1

ii) calculating C_j(i)=C([i×

p_j] mod(p−

1)), where j=0,1,2, . . . , (R−

1), i=0,1,2, . . . , (p−

1), C_j(p−

1)=0, and C_j(p)=p

iii) exchanging C<sub>R−

1</sub>(p) with C<sub>R−

1</sub>(0)

where p (prime number) indicates a prime number which is closest to K/R, g0 (primitive root) indicates a predetermined number corresponding to p, p_j indicates a primitive number set, and c_j(i) is the input bit position of an ith output after the permutation of a jth row.

16. A 2-dimensional interleaving method comprising the steps of:

sequentially writing input sequences of information bits of the frame in an R×

C rectangular matrix;

selecting a primitive root g0 corresponding to the minimum prime number p, and generating a base sequence c(i) for intra-row permuting the input sequences written in the rows in accordance with