EURASIP Journal on Applied Signal Processing
Volume 2005 (2005), Issue 6, Pages 928-941
doi:10.1155/ASP.2005.928
Abstract
The error robustness of digital communication systems
using source and channel coding can be improved by iterative
source-channel decoding (ISCD). The turbo-like evaluation of
natural residual source redundancy and of artificial channel
coding redundancy makes step-wise quality gains possible by
several iterations. The maximum number of profitable iterations is
predictable by an EXIT chart analysis. In this contribution, we
exploit the EXIT chart representation to improve the error
correcting/concealing capabilities of ISCD schemes. We propose new
design guidelines to select appropriate bit mappings and to design
the channel coding component. A parametric source coding scheme
with some residual redundancy is assumed. Applying both
innovations, the new EXIT-optimized index assignment as
well as the appropriately designed recursive nonsystematic
convolutional (RNSC) code, allows to outperform known approaches
to ISCD by far in the most relevant channel conditions.