Viterbi decoding method

• US 20080109710A1
• Filed: 10/31/2007
• Published: 05/08/2008
• Est. Priority Date: 11/02/2006
• Status: Abandoned Application

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Takanashi, Mitsunori
• Application Number:
  US11/980,658
• Publication Number:
  US 20080109710A1
• Time in Patent Office: Days
• US Class Current: 714/799
• CPC Class Codes: H03M 13/09 Error detection only, e.g. using cyclic redundancy check [CRC] codes or single parity bit
• CPC Class Codes: H03M 13/3738 with judging correct decoding
• CPC Class Codes: H03M 13/4115 list output Viterbi decoding

Abstract

A decoding method relative to this application improves an error correction performance without increasing a memory. The decoding method includes obtaining a first decoded result from a first decoding path being on a trellis diagram; determining whether the first decoded result is incorrect or not; creating a second decoding path when the first decoded result is incorrect; and obtaining a second decoded result from the second decoding path.

Claims

1. A decoding method comprising:

obtaining a first decoded result from a first decoding path being on a trellis diagram;

determining whether the first decoded result is incorrect or not;

creating a second decoding path when the first decoded result is incorrect; and

obtaining a second decoded result from the second decoding path.

2. The decoding method according to claim 1, wherein

the first decoding path includes a first branch connecting a first state and a second state, the second state being at a time point previous to the first state and

the second decoding path includes a second branch connecting the first state and a third state, the third state being different from the second state and at a time point equal to the second state.

3. The decoding method according to claim 2, further comprising:

determining whether the second decoded result is incorrect or not;

creating a third decoding path when the second decoded result is incorrect; and

obtaining a third decoded result from the third decoding path.

4. The decoding method according to claim 3, wherein

the first decoding path further includes a third branch connecting the second state and a fourth state, the fourth state being at a time point previous to the second and third states and

the third decoding path includes the first branch and a fourth branch connecting the second state and a fifth state, the fifth state being different from the fourth state and at a time point equal to the fourth state.

5. The decoding method according to claim 4, wherein creating a new decoding path and obtaining a new decoded result are repeated till a correct decoded result is obtained.

6. The decoding method according to claim 4, wherein creating a new decoding path and obtaining a new decoded result are repeated predetermined number of times.

7. The decoding method according to claim 1, wherein the first decoding path has the highest likelihood in decoding paths being on the trellis diagram.

8. The decoding method according to claim 1, wherein the second decoding path has the second highest likelihood in the decoding paths.

9. The decoding method according to claim 2, wherein the first state is a final state being at a final time point of the trellis diagram.

10. The decoding method according to claim 1, wherein the first decoded result is obtained by performing a trace back on the trellis diagram.