Error protection and packet loss concealment based on a signal matched sinusoidal vocoder

We propose an error protection and packet loss concealment system, based on a modified sinusoidal vocoder. By means of a few additional phase parameters, the vocoder is able to partially track the original signal during voiced segments. This signal tracking allows us to switch seamlessly between the vocoded signal and a primary encoded signal. A packetized speech transmission system, using PCM data as primary encoding, and the modified vocoder as a sub-coder, is simulated and evaluated using subjective preference testing. Packet loss concealment based on extrapolation of the vocoder parameters is found to perform well, especially at high error rates.