On improving voice quality degraded by packet loss in data networks

In voice over data networks, packet loss can have a major impact on perceived voice quality. The impact of packet loss on perceived voice quality depends on several factors, including loss pattern, codec type and packet size. Many techniques have been developed to recover lost packets. A newly developed recovery technique, "switched recovery technique" (SRT), employs a suitable recovery technique from known techniques to estimate the lost packet content (silence/voiced/unvoiced), depending on the preceding and following packets that were received correctly. The proposed technique was tested with different codecs, such as LD-CELP, LPC-10, and variable rate coders. Two loss models, random model and burst model, have been used to simulate the packet loss