Error protection to IS-96 variable rate CELP speech coding

IS-96 describes a variable rate code-excited linear prediction (CELP) speech coder in code division multiple access (CDMA) digital cellular environment. In this work we focus on the study of the error protection methods in CDMA cellular environments. We find that although the error protection technique described in IS-96 can improve the speech quality in noisy channels considerably, the error concealment effect in IS-96 can be further improved by a better bit protection pattern without increasing the processing complexity