A New Technique for Improving Quality of Speech in Voice over IP Using Time-Scale Modification

Packet arrival-delay variations and losses seriously affect the quality of voice delivered in VoIP. In this paper, using a time-scale modification algorithm, an integrated scheme is proposed to handle these impairments without introducing additional delays. This scheme provides flexible arrival-delay cut-offs to late arriving packets, reducing the packet loss-rate at the receiver. Further, the lost packets are concealed effectively. Extensive simulations have shown that the proposed scheme delivers high-quality speech across widely varying packet arrival-delays and loss-rates. The proposed scheme is fully receiver-based and with its low computational complexity and generic nature, is applicable to any VoIP system