Cross-Layer Rate Allocation for Multimedia Applications in Pervasive Computing Environment

An important issue for supporting multimedia applications in multiple heterogeneous networks, a typical pervasive computing environment, is how to optimize the rate allocation by intelligently utilizing the available network resources while, at the same time, to meet each application´s QoS (Quality of Service) requirement. In this work, we develop and evaluate a rate allocation scheme in terms of audio and video applications based on a cross-layer design framework. At first, we construct a general distortion model according to the observed parameters in each network, as well as each application´s rate-distortion characteristic. Then, the rate allocation is formulated as a convex optimization problem that minimizes the sum of the expected distortion of all applications. Furthermore, the realization of the distributed rate allocation algorithm for achieving an optimal or close-to-optimal end-to-end QoS under the overall limited resource budget is the highlight of this paper. Simulation results are provided which demonstrate the effectiveness of our proposed distributed rate allocation scheme.