New ARQ protocol for interactive video over data networks

In this paper we introduce a new ARQ protocol for resilient multicast interactive video applications over error-prone LANs and MANs. Our proposal maximizes overall video quality and channel capacity in a session by means of coding and transmission policies based on communication statistics feedback. Transmitters prioritize session members with best reception statistics to take advantage of the high compression rates and quality available through predictive video coding. Missing or corrupted frames at the receivers are notified through a novel multicast repair-request protocol, with new ARQ-suppression algorithms, that allows fast resynchronization with the transmitters. Our scheme does not depend on intra-coded information to catch up on incomplete video sequences at the receivers. It provides maximum video quality, optimum resource utilization, and a very efficient error-propagation control mechanism at a negligible cost in bandwidth for the stations requesting repair information. We demonstrate, through quantitative results from videoconferencing experiments in wireless LANs, that the proposed ARQ strategy is an efficient solution for such applications. Experimental results report negligible video degradation and fast error-correction times for high frame error rate values.