This paper describes the basic performance requirements for a new enhanced GSM codec and a proposal for this application based on the ITU 8 kb/s coder standard. A powerful channel wding scheme using more than half the gross bit rate is designed and the performance of the codec ir formally evaluatedusing MOS testing. The overall system is found to provide toll qudity speech with only a graceful degradation at increasing bit error rates, and it meets the preliminary quality requirements for the new standard.