Source: Acoustics, Speech and Signal Processing, 1998. Proceedings of the 1998 IEEE International Conference on, Nokia Research Center, Volume 1, p.141 -144 vol.1 (1998)
Publication Type: Article
Abstract: This paper describes a multi-rate codec family developed as a
potential candidate for the GSM adaptive multi-rate (AMR) codec
standard. The codec family consists of the GSM enhanced full rate (EFR)
codec and lower bit-rate extensions thereof. The codec family consists
of several codecs, i.e., modes that have different bit-rate
partitionings between source coding and error protection. All the source
codecs use the same ACELP-method (algebraic code excited linear
predictive coding) used also in the GSM EFR codec. The codec operates at
gross bit-rates of 22.8 kbit/s in the GSM full rate (FR) channel and
11.4 kbit/s in the GSM half rate (HR) channel. In the full rate channel,
the codec provides improved error robustness over the GSM enhanced full
rate (EFR) codec. It extends wireline quality (equal to or better than
G.726-32 ADPCM) to poor channel error conditions with low C/I-ratios of
7 dB or even below. When operated in the half rate channel, the codec
provides improved channel capacity while still providing wireline
quality at high C/I-ratios above 16-19 dB
Links:
