8th International Conference on Spoken Language Processing

Jeju Island, Korea
October 4-8, 2004

Soft Features for Improved Distributed Speech Recognition over Wireless Networks

Reinhold Haeb-Umbach, Valentin Ion

University of Paderborn, Germany

A major drawback of distributed versus terminal-based speech recognition is the fact that transmission errors can lead to degraded recognition performance. In this paper we employ "soft features" to mitigate the effect of bit errors on wireless transmission links: At the receiver a posteriori probabilities of the transmitted feature vectors are computed by combining bit reliability information provided by the channel decoder and a priori knowledge about residual redundancy in the feature vectors. While the first-order moment of the a posteriori probability function is the MMSE estimate, the second-order moment is a measure of the uncertainty in the reconstructed features. We conducted realistic simulations of GSM transmission and achieved significant improvements in word accuracy compared to the error mitigation strategy described in the ETSI standard.

Full Paper

Bibliographic reference.  Haeb-Umbach, Reinhold / Ion, Valentin (2004): "Soft features for improved distributed speech recognition over wireless networks", In INTERSPEECH-2004, 2125-2128.