This paper presents a forward error correction (FEC) technique based on a multipulse representation of the excitation for code-excited linear prediction (CELP) speech transmission under packet loss conditions. In this approach, the encoder sends the position of a pulse that it is used for the resynchronization of the adaptive codebook, so that propagation errors can be prevented. At the decoder, the amplitude of the resynchronization pulse is estimated by means of minimum mean square error (MMSE) estimation based on Gaussian mixture models (GMMs) of the received parameters and the pulse amplitude. The proposal is tested employing PESQ scores and AMR 12.2 kbps, a well-known CELP codec. The results show that, with a very small additional information (350 bps), this technique achieves a noticeable improvement over the results obtained by the packet loss concealment included in the legacy codec.
Bibliographic reference. Carmona, José L. / Gómez, Angel M. / Peinado, Antonio M. / Pérez-Córdoba, José L. / González, José A. (2010): "A multipulse FEC scheme based on amplitude estimation for CELP codecs over packet networks", In INTERSPEECH-2010, 2386-2389.