ENHANCED CHANNEL CODING USING SOURCE CRITERIA IN SPEECH CODERS

Spectral efficiency in digital voice communications in personal commun ications networks is primarily provided for by advanced speech coding techniques. A threat to the quality and low bit rate requirements of t hese speech coders is imposed by the transmission channel. Channel cod ing is thus considered mandatory, but its performance is limited to sp ecific channel conditions and system constraints like bandwidth and tr ansmission power. The authors describe a technique for exploiting sour ce redundancy in speech coders for further improving the performance o f the channel coding scheme without the obligatory increased redundanc y.