Abstract-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.

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International audienceAs multimedia is expected to be a major traffic source in the next-generation wireless networks, there have been increasing concerns about the security issues of wireless transmission of multimedia in recent years. Wireless networks, by their natures, are more vulnerable to external intrusions than wired ones. Therefore, many applications demand authenticating the integrity of multimedia content delivered wirelessly. In this work, we propose a framework for jointly authenticating and coding multimedia to be transmitted over heterogeneous wireless networks. We firstly provide a novel graph-based authentication scheme which can not only construct the authentication graph flexibly but also trade-off well among some practical requirements such as overhead, robustness and delay. And then, a rate-distortion optimized joint source-channel coding (JSCC) approach for error-resilient scalable encoded video is presented, in which the video is encoded into multiple independent streams and each stream is assigned forward error correction (FEC) codes to avoid error propagation. Furthermore, we consider integrating authentication with the specific JSCC scheme to achieve a satisfactory authentication results and end-to-end reconstruction quality by optimally applying the appropriate authentication and coding rate. Simulation results show the effectiveness of the proposed authentication-coding scheme for multimedia over wireless networks

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Distributed scheduling for hybrid media flows over wireless body sensor network faces three technical challenges: constrained communication channel, random node placement and strict transmission latency. In this work, we study this problem by jointly considering the above three challenges to achieve the minimum media distortion and optimal network resource utilization. At first, we construct a general flow transmission model according to network's transmission mechanism, as well as media-aware flow's characteristics. Then, a distributed scheduling scheme is proposed based on dynamic network resource update. It is proved that the proposed scheme can achieve the optimal scheduling solution with an exponential convergence rate, and an explicit form of the asymptotic convergence rate is provided. Furthermore, the realization of the distributed scheduling scheme through the collaboration between the network and the sources is the highlight of this paper. Extensive simulation results are provided to demonstrate the effectiveness of our proposed scheme.