Speech Packet Concealment Techniques Based on Time-Scale Modification for VoIP

With the availability of large bandwidth and high data rates the transmission of data, voice and video over the Internet is gaining popularity. Voice-over-IP (VoIP) uses packetized transmission of speech over the Internet (IP network). However, at the receiving end; packets are missing due to network delay, network congestion (jitter) and network errors. This packet loss degrades the quality of speech at the receiving end of a voice transmission system in an IP network. Since the voice transmission is a real-time process, the receiver cannot request for retransmission of the missing packets. This causes a need for reconstruction of the lost packet. Concealment algorithms, either transmitter or receiver based, are used to replace these lost packets. The goal of this paper is to review the different PLC algorithm on the receiver side.