Error concealment schemes for speech packet transmission over IP network

The transmission of voice over packet switched networks, such as an Internet Protocol (IP), is an area of active research. The speech packets when transmitted over unreliable IP networks, such as the internet, may encounter losses due to dropped packets or late arrivals. This packet loss may change the meaning of senders message as well degrades the quality of speech at the receiving end of a voice transmission system over network. Since the voice transmission is a real-time process, request of retransmission of the missing packets is unpredictable. concealment of packet loss algorithms, either transmitter or receiver based, are used to replace these lost packets. This paper is to study (reviews) the error-concealment schemes for speech packet transmission over the Internet. The existing techniques can be classified into source coder-dependent schemes that exploit coder-specific characteristics to perform reconstruction and source coder-independent schemes .These techniques are use to solve the problem of loss of speech packets over IP to improve the perceived speech quality.