ISCA Archive Eurospeech 1993
ISCA Archive Eurospeech 1993

Enhancing robustness of coded LPC-spectra to channel errors by use of residual redundancy

Stefan Feldes

In this paper a method is presented to enhance the performance of the error control scheme in speech transmission in a mobile radio system by the use of residual redundancy in the coded speech parameters. In particular the LPC spectral coefficients are considered here. The proposed scheme is located on the receiver side and consists of a combination of two estimators, a MLSE channel error correction unit with reliability output and a parameter estimator based on 'a-priori knowledge' about source statistic. The results in terms of objective measures and informal listening show that especially for very bad channel conditions significant improvements can be achieved and that computationally less complex variants yielded the best results.

Keywords: Residual redundancy, LPC spectrum, Channel error correction, Softdecision Viterbi, Maximum Likelihood / MMSE - Estimation