Sixth European Conference on Speech Communication and Technology
(EUROSPEECH'99)

Budapest, Hungary
September 5-9, 1999

Joint Source-Channel Decoding by Channel-Coded Optimal Estimation (CCOE) for a CELP Speech Codec

Norbert Görtz

Institute for Circuits and Systems Theory, University of Kiel, Germany

A new algorithm called Channel-Coded Optimal Estimation (CCOE) is adapted to a CELP speech codec. The CCOE-algorithm performs joint source-channel decodingby optimal estimation using bit-reliability informations(soft-bits) and source statistics. The basic algorithm fora simple transmission scenario with a single scalar quantizer has been recently stated by the author. In this paper the basic idea is extended for the use in a CELPspeech-codec that was developed for enhanced speechtransmission in the GSM mobile radio channel. Simulation results based on informal listening tests are givenwhich show that the new algorithm achieves substantialgains over separate error correction with hard decisionsprior to source decoding and classical techniques for error detection and bad frame handling as widely used in the present mobile-radio systems.


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Bibliographic reference.  Görtz, Norbert (1999): "Joint source-channel decoding by channel-coded optimal estimation (CCOE) for a CELP speech codec", In EUROSPEECH'99, 1447-1450.