Error Concealment of EVRC Speech Decoder Using Residual Redundancy

In digital mobile communication systems, speech coding is very important to increase the bandwidth efficiency. Usually, speech coding algorithms determine speech parameters, which are highly sensitive to transmission errors. In this paper, we use the residual redundancy remaining after using the Enhanced Variable Rate Codec (EVRC) algorithm for error concealment. Average residual redundancies of the quantized parameters are exploited in the error concealment process as a priori knowledge of the source. The simulation results show that the use of error concealment improves the parameter SNRs of these parameters, especially for Pitch delay, Delta delay and Fixed Codebook (FCB) gain. The results also show that the more redundancy exists in the encoded parameter, the more improvement we could obtain by using the error concealment scheme.