Proceedings ArticleDOI
Vector quantization over a noisy channel using soft decision decoding
Mikael Skoglund,Per Hedelin +1 more
- pp 605-608
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TLDR
The interesting case, for applications, of using an ordinary VQ codebook as encoder, together with the soft decision decoder, gives comparable performance to channel optimized VQ with hard decisions.Abstract:
A soft decision decoder is presented. The soft decision decoder is optimal in the mean square sense, if the encoder entropy is full. A source vector estimate is obtained as a linear mapping of a soft Hadamard column. The soft Hadamard column is formed as a generally nonlinear mapping of soft information bits. It is shown that the best index assignment, on the encoder, is obtained in the special case of a linear mapping from the soft information bits. Simulations indicate that the jointly trained system performs better than channel optimized VQ with hard decisions. The interesting case, for applications, of using an ordinary VQ codebook as encoder, together with our soft decision decoder, is also investigated. In our examples this approach gives comparable performance to channel optimized VQ with hard decisions. >read more
Citations
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Journal ArticleDOI
Softbit speech decoding: a new approach to error concealment
Tim Fingscheidt,Peter Vary +1 more
TL;DR: A new and generalizing approach to error concealment is described as part of a modified robust speech decoder that can be applied to any speech codec standard and preserves bit exactness in the case of an error free channel.
Journal ArticleDOI
Soft decoding for vector quantization over noisy channels with memory
TL;DR: A recursive implementation of optimal soft decoding for vector quantization over noisy channels with finite memory and an approach to suboptimal decoding, of lower complexity, being based on a generalization of the Viterbi algorithm are considered.
Journal ArticleDOI
Hadamard-based soft decoding for vector quantization over noisy channels
Mikael Skoglund,Per Hedelin +1 more
TL;DR: Through numerical simulations, soft decoding is demonstrated to outperform hard decoding in several aspects and an efficient algorithm for optimal decoding is derived.
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HMM-based channel error mitigation and its application to distributed speech recognition
TL;DR: A hidden Markov model (HMM) framework from which different mitigation techniques oriented to wireless channels can be derived is proposed, showing that the HMM-based techniques can effectively mitigate channel errors, even in very poor channel conditions.
Journal ArticleDOI
Transactions Papers source-optimized channel coding for digital transmission channels
S. Heinen,Peter Vary +1 more
TL;DR: A new class of nonlinear block codes called source-optimized channel codes (SOCCs), which are particularly designed for parametric source encoding of speech, audio, and video, which are not optimized for minimizing residual bit-error rate, but maximizing the signal-to-noise ratio of transmitted source codec parameters.
References
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Journal ArticleDOI
On the performance and complexity of channel-optimized vector quantizers
TL;DR: It is demonstrated that for very noisy channels and a heavily correlated source, when the code book size is large, the number of encoding regions is considerably smaller than the codebook size-implying a reduction in encoding complexity.
Journal ArticleDOI
Joint design of block source codes and modulation signal sets
TL;DR: It is demonstrated that the MSE of a bandwidth and energy constrained digital system is bounded from below by that of a block pulse amplitude modulation system, and significant performance improvements over the standard VQ-based system are demonstrated when the channel is noisy.
Proceedings ArticleDOI
How good is your index assignment
TL;DR: Two fast and reliable methods of evaluating the inherent structure of a robust VQ without explicit knowledge about the training or the source are presented and the validity of the linearity measurement for encoders without full entropy is discussed.
Proceedings ArticleDOI
Robust Vector Quantization by Linear Mappings of Block-codes
R. Hagen,Per Hedelin +1 more
Proceedings ArticleDOI
Soft Decision Vector Quantization for Noisy Channels
V. Cuperman,Feng-Hua Liu,P. Ho +2 more
TL;DR: It is shown that SDVQ achieves a significant performance improvement over both the source optimized VQ and the channel optimize VQ.