Title :
A 6.1 to 13.3-kb/s variable rate CELP codec (VR-CELP) for AMR speech coding
Author :
Heinen, S. ; Adrat, M. ; Steil, O. ; Vary, P. ; Xu, W.
Author_Institution :
Inst. of Commun. Syst. & Data Process, Aachen Univ. of Technol., Germany
Abstract :
We propose a new 6.1 to 13.3-kb/s speech codec called variable rate code-excited linear prediction (VR-CELP) for adaptive multi-rate (AMR) transmission over mobile radio channels such as GSM or UMTS. The AMR concept allows to operate with almost wireline speech quality for poor channel conditions and better quality for good channel conditions. This is achieved by dynamically splitting the gross bit rate of the transmission system between source and channel coding according to the current channel conditions. Thus the source coding scheme must be designed for seamless switching between rates without annoying artifacts. To enhance the transmission quality under very poor channel conditions, a new powerful error concealment strategy based on estimation theory is applied
Keywords :
adaptive codes; channel coding; estimation theory; linear predictive coding; mobile radio; source coding; speech codecs; speech coding; variable rate codes; 6.1 to 13.3 kbit/s; AMR transmission; GSM; UMTS; VR-CELP; adaptive multi-rate transmission; channel coding; error concealment strategy; estimation theory; good channel conditions; gross bit rate splitting; mobile radio channels; poor channel conditions; source coding; speech coding; variable rate CELP codec; variable rate code-excited linear prediction; wireline speech quality; Bit rate; Decoding; Encoding; Iterative algorithms; Linear predictive coding; Speech analysis; Speech codecs; Speech coding; Testing; Vector quantization;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1999. Proceedings., 1999 IEEE International Conference on
Conference_Location :
Phoenix, AZ
Print_ISBN :
0-7803-5041-3
DOI :
10.1109/ICASSP.1999.758049
