Playout scheduling and lossconcealments in VoIP for optimizing conversational voice communication quality

In this paper, we present new adaptive playout scheduling (POS) and loss-concealment (LC) schemes for delivering high and consistent conversational voice communication quality (CVCQ) perceived by users in real-time VoIP systems. We first characterize the delay and loss conditions of an IP network and a human conversation in a VoIP system. We then identify the attributes that affect the human perception of CVCQ, which include listening-only speech quality (LOSQ), conversational interactivity (CI), and conversational efficiency (CE). We investigate their trade-offs with respect to system-controllable mouth-to-ear delays (MEDs) and the amount of redundant piggybacking. Finally, we evaluate our adaptive POS and redundancy-based LC schemes by packet traces collected in the PlanetLab. Categories and Subject Descriptors H.4.3 [Information Systems Applications]: Communication