Scalable MPEG-4 Streaming over the Mobile Networks Environment

Abstract

When a mobile client is moving from subnet to subnet and connects to the same proxy all the way, the transmission quality can not be guaranteed. Thus, the mobile client must switch to a new proxy when it moves to a new subnet. In this paer, we define the procedure of switching the served proxies dynamically as ”proxy handoff”. In order to solve proxy handoff, a Layered Video Handoff Mechanism (LVHM) based on the scalable MPEG-4 streaming technique is proposed and implemented. LVHM analyzes the situation of cached data in the original proxy and the new proxy, and then decide whether the original server needs to forward the cached data to the new proxy or not. Once the forwarding procedure is required, LVHM can forward the cached video frames according to priority. Two experiments are designed and presented that LVHM can cost less time than receiving data from the corresponding server even if the network is congested.