Adaptive media streaming in heterogeneous wireless networks

In this paper we present a system for IP based networks which adapts media streams to the respective characteristics of different (wireless) access networks. Inside the mobile node, an interface selection subsystem monitors characteristics of network interfaces and triggers vertical handovers based on policies supplied by the operator. A service subsystem initiates media stream adaptation to match network resource availability and provider constraints. A media subsystem on mobile and correspondent node transmits the media streams and applies appropriate error correction mechanisms (like FEC, ARQ) depending on network characteristics. We evaluate vertical handover behaviour of our system in a combined GPRS - WLAN testbed and analyze the impact of several error correction mechanisms on the perceived video quality.