  An optimal frame transmission scheme is presented for streaming scalable
video over a link with limited capacity. The objective is to select a
transmission sequence of frames and their transmission schedule such that the
overall video quality is maximized. The problem is solved for two general
classes of hierarchical prediction structures, which include as a special case
the popular dyadic structure. Based on a new characterization of the
interdependence among frames in terms of trees, structural properties of an
optimal transmission schedule are derived. These properties lead to the
development of a jointly optimal frame selection and scheduling algorithm,
which has computational complexity that is quadratic in the number of frames.
Simulation results show that the optimal scheme substantially outperforms three
existing alternatives.
