AMR Codec Mode Selection in TD-SCDMA

Adaptive multi-rate (AMR) codec was standardized for TD-SCDMA by 3GPP (3rd Generation Partnership Project) in 1999. Comparing with previous GSM speech codec, one of AMR code´s characteristics is offering adaptive code rates. To AMR codec mode, how to switch from one rate to another according to the radio network condition is a research hotspot in recent years. This paper gives a description about the process of AMR codec mode selection. Applying the MCD (Mel-cepstral distance) measure to the analysis of performances of AMR´s eight rates, this paper gives a division to the eight rates. And then, by doing experiments, an ACS with better performance is concluded.