Packet Loss Concealment Using Time Scale Modification for CELP Based Coders in Packet Network

In this paper, we propose a method for packet loss concealment (PLC) based on time scale modification for code excited linear prediction (CELP) based coders in packet network. We perform a time scale modification (TSM) using a waveform similarity overlap-add (WSOLA) technique which is an interpolation-based method operating entirely in the time domain, to reconstruct the excitation signal of the lost frame. We applied the proposed scheme to the standard ITU-T G729 standard speech coder to evaluate the proposed method. The perceptual evaluation of speech quality (PESQ) and enhanced modified bark spectral distortion (EMBSD) tests under various packet loss conditions confirm that the proposed algorithm is superior to the concealment algorithm embedded in the G729.