An improved packet loss concealment technique for speech transmission in VOIP

Packet loss is a major source of voice distortion in VoIP (Voice over IP). Packet loss may be due to several reasons: routing problems, transmission errors, and network congestion in VoIP communications. To mitigate the effect of these losses on voice quality, PLC (Packet Loss Concealment) mechanisms are introduced in the decoders to reconstruct the lost frames. Many decoders have PLC algorithms as G729.A and G723.1. This decoders generally have bad correcting losses when there are many consecutive lost packets. For reinforce the PLC algorithm performance of decoders, several PLC techniques used both at the receiver level such as PLC technique based on ITU-T G711 Appendix I, then is longer used in VoIP. In this paper, we proposed the method of polynomial interpolation integrate at PLC technique based on ITU-T G711 Appendix I, for finding the synthetic signal approximation as an original signal by interpolating samples of pitch. Evaluation results of subjective PESQ confirmed that method proposed can effectively evaluate the speech quality in the IP environment.