Streaming Agent: A Network Proxy for Media Streaming in 3G Wireless Networks

Streaming media in 3G wireless networks means the streaming server must simultaneously adapt the media content to two mediums of drastically different characteristics: an often congested wired network and an unreliable wireless link. To improve the server’s media adaptiveness, we enhance a previously proposed network proxy, located at the junction of the wired network and wireless link, to provide timely feedbacks to the server. The enhanced proxy is called Streaming Agent (SA). SA timely feedbacks provide partial path information for the server to track the wired client state — which packets have arrived correctly and on-time at SA. Armed with knowledge of wired client state, the server can in real-time better adapt the streaming content accordingly. We demonstrate SA’s usefulness in the context of the format-adaptation problem: two video streams with the same bit rate but different I-frame frequencies are switched back and forth depending on SA and/or client timely feedbacks. We show that using a scheme that adapts to both SA and client feedbacks, visual quality can be improved up to 0.78dB at 230kbits/s over a scheme that adapts to client feedbacks only.