Combining FEC and optimal soft-input source decoding for the reliable transmission of correlated variable-length encoded signals

We utilize both the implicit residual source correlation and the explicit redundancy from a forward error correction (FEC) scheme for the error protection of packetized variable-length encoded source indices. The implicit source correlation is exploited in a novel symbol-based soft-input a-posteriori probability (APP) decoder, which leads to an optimal decoding process in combination with a mean-squares or maximum a-posteriori probability estimation of the reconstructed source signal. When, additionally, the variable-length encoded source data is protected by channel codes, an iterative source-channel decoder can be obtained in the same way as for serially concatenated codes, where the outer constituent decoder is replaced by the proposed APP source decoder. Simulation results show that, by additionally considering the correlations between the variable-length encoded source indices, the error-correction performance can be highly increased.

[1]  David J. Miller,et al.  Joint source-channel decoding for variable-length encoded data by exact and approximate MAP sequence estimation , 1999, 1999 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258).

[2]  Jörg Kliewer,et al.  Soft-input source decoding for robust transmission of compressed images using two-dimensional optimal estimation , 2001, 2001 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No.01CH37221).

[3]  John Cocke,et al.  Optimal decoding of linear codes for minimizing symbol error rate (Corresp.) , 1974, IEEE Trans. Inf. Theory.

[4]  N. Gortz On the iterative approximation of optimal joint source-channel decoding , 2001 .

[5]  John D. Villasenor,et al.  Utilizing soft information in decoding of variable length codes , 1999, Proceedings DCC'99 Data Compression Conference (Cat. No. PR00096).

[6]  Khalid Sayood,et al.  Joint source/channel coding for variable length codes , 2000, IEEE Trans. Commun..

[7]  Joachim Hagenauer,et al.  Iterative decoding of binary block and convolutional codes , 1996, IEEE Trans. Inf. Theory.

[8]  Dariush Divsalar,et al.  Turbo codes for PCS applications , 1995, Proceedings IEEE International Conference on Communications ICC '95.

[9]  Christine Guillemot,et al.  Joint source-channel turbo decoding of VLC-coded Markov sources , 2001, 2001 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No.01CH37221).

[10]  Joachim Hagenauer,et al.  Symbol-by-Symbol MAP Decoding of Variable Length Codes , 2000 .