Efficient multicast video streaming over heterogeneous networks

Sammanfattning: The demand for real-time video streaming over Internet is ever growing. The aggregated bandwidth of the video flows can be substantial, which motivates the use of bandwidth-preserving techniques such as multicast transmission and powerful source coding algorithms. With powerful video source coding follow an increased sensitivity to lost or corrupted data. Error-correcting codes may be applied to deal with this side effect. Another topic, which arises when multicast is introduced, is its effect on the notion of fairness. It is debatable if a unicast flow with a single receiver should be entitled to the same amount of bandwidth as a multicast flow with hundreds of receivers. This licentiate thesis aims at exploiting and combining existing techniques and developing new ones, all with the common goal of creating higher satisfaction and fairness for the end users of video streaming services. One of the techniques that are being evaluated is priority dropping, where less important packets are the first to be dropped in the routers in case of congestion. Then a scheme where multicast end users can deal with varying packet-loss rates by individually choosing the amount of error-correcting data they want to receive, is proposed. Further, the area of fairness in multicast environments is addressed, and a new definition of multicast fairness is presented.