A new low bit rate low delay algebraic CELP (ACELP) coder

Abstract

The coders based upon ITU-T G.729 standard and its new version G.729A provide toll-quality speech for most operating conditions, and these coders are the prime candidates for the next generation of cellular systems. This paper presents new techniques for reducing the bit rate of these coders from 8 kbits/s to 7 kbits/s without introducing any bad effects into the coders' performance in clean or noisy environments, and without increasing the codec delay. The new coder is called algebraic CELP (ACELP) and has 7 kbits/s with 15 ms algorithmic delay.