Proxy-based error tracking for H.264 based real-time video transmission in mobile environments

Error tracking (ET) is an error resilience technique for real-time video transmission over error-prone communication channels. In this paper we propose proxy-based ET for communication scenarios where the sender is in the wired Internet and the receiver is connected via a wireless link. Our main assumptions in this work are that there is a strong imbalance between the transmission rates available in the wired and the wireless Internet and that the round-trip delay is mainly caused by the wired part of the connection. We also assume that the majority of the packet loss is caused by the wireless link. In order to allow the proxy server to perform error tracking, an additional update stream is sent through the wired network. This additional information is used by the proxy to improve the performance on the wireless link We show that under these assumptions proxy-based error tracking leads to significantly improved performance for H.264 based real-time video communication in comparison to traditional end-to-end error tracking