Robust GSM Speech Decoding Using the Channel Decoder's Soft Output

Authors:

Fingscheidt, T. ,  Scheufen, O.

Book Title:

Proceedings of European Conference on Speech Communication and Technology (EUROSPEECH)

Organization:

ESCA

Pages:

p.p. 1315-1318

Address:

Rhodes, Greece

Date:

Sep. 1997

Language:

English

Abstract

In the digital mobile radio system GSM (Global System for Mobile Communications) there is a need for reducing the subjective effects of residual bit errors by error concealment techniques. Due to the fact that the standard does not specify these algorithms bit exactly, there is room for new solutions to improve the decoding process. This contribution presents a new approach for optimum estimation of speech codec parameters applied to the GSM system. It requires a soft-output channel decoder (e.g. soft-output Viterbi algorithm - SOVA) providing a bit reliability information for the proposed parameter estimation process. Additionally, a priori knowledge about the residual redundancy in the sequence of codec parameters is exploited. The new method includes an inherent muting mechanism leading to a graceful degradation of speech quality in case of adverse transmission conditions. If the channel is error free, bit exactness as required by the GSM standard is preserved.

Download

BibTeX

Copyright © by IKS
fingscheidt97c.pdf

This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.

---