From heuristic to theoretical: a new design methodology for cross-layer optimized wireless multimedia streaming

Cross-layer design has been widely perceived as an effective and efficient method for QoS provisioning in wireless networks. Because of this, a lot research has been done in this area. However, most existing crosslayer schemes reported in literature are carried out by using piecemeal approach - only part of control knobs are considered in the cross-layer optimization under various application and network scenarios, where only local optimality can be achieved. Recently, it has been getting more and more research interests to develop a global cross-layer optimization framework. However, these efforts heavily rely on heuristic approaches, which is lack of sound engineering judgement and cannot provide much design insights in QoS provisioning in both current and future multimedia communication systems. In this paper, we propose a rigorous global cross-layer optimization method by using a topdown approach based on the delay-quality framework. Both theoretical analysis and experimental results show the effectiveness of the proposed framework. The top-down theoretical formulation for global cross-layer control and optimization also provides a common ground for evaluating and comparing various cross-layer designs. Moreover, the proposed theoretical framework resides in control plane and does not break syntax and semantics of the layered network architecture.