This paper describes recent approaches to speech coding at low bit rates with an emphasis on existing and upcoming standards and with a preference given to those coders where subjective quality scores were available. Speech coders for mobile radio are covered in some detail. A good to excellent speech coding quality can be achieved with bit rates of 1 b/sample (8 kb/s), expectations are that the rates can be reduced to less than 0.5 b/sample (4 kb/s) within the next decade. Not covered are important issues of complete speech communications links, such as sensitivity to and protection against bit errors or cell losses, adaptive noise suppression, and others.
Keywords: Speech Coding, Source Coding, Digital Networks, Mobile Radio, Cordless Telephony.
Bibliographic reference. Noll, Peter (1993): "Speech coding for communications", In EUROSPEECH'93, 479-488.