A High Performance Serially Mixed SOVA Decoder for Turbo Code

Sang-Sic YOON
Hyung-Chul PARK
Kwyro LEE

IEICE TRANSACTIONS on Communications   Vol.E85-B    No.1    pp.332-335
Publication Date: 2002/01/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Fundamental Theories
turbo,  SOVA,  decoder,  backward,  bidirectional,  

Full Text: PDF>>
Buy this Article

The backward direction Soft Output Viterbi Algorithm (a backward SOVA) is compared with the conventional SOVA (a forward SOVA) in turbo code decoding. We find noticeable performance improvement for the backward SOVA when it is not terminated, which turns out to be due to a smaller reliability value, indicating that the termination conditions of the turbo encoder strongly affect the performance of the backward SOVA decoder. We also propose a hardware efficient serially mixed SOVA decoder composed of a forward SOVA decoder and a backward SOVA decoder. Simulation results show that the proposed serially mixed SOVA decoder has a 0.2 dB coding gain at 2.0 dB Eb/No over the forward SOVA for a typical turbo code example.