A Theoretical Framework for Interaction Measure and Sensitivity Analysis in Cross-Layer Design

Cross-layer design has become one of the most effective and efficient methods to provide Quality of Service (QoS) over various communication networks, especially over wireless multimedia networks. However, current research on cross-layer design has been carried out in various piecemeal approaches, and lacks a methodological foundation to gain in-depth understanding of complex cross-layer behaviors such as multiscale temporal-spatial behavior, leading to a design paradox and/or unmanageable design problems. In this article, we propose a theoretical framework for quantitative interaction measures, which is further extended to sensitivity analysis by quantifying the contribution made by each design variable and by the interactions among them on the design objective. Thus, the proposed framework can significantly enhance our capability for cross-layer behavior characterization and provide design insights for future design. Furthermore, a case study on cross-layer optimized wireless multimedia communications has been adopted to illustrate major cross-layer design trade-offs and validate the proposed framework. Both analytical and experimental results show the correctness and effectiveness of the proposed framework.