QoS Oriented Cross-Layer Design for Improving Multimedia Transmissions over Cooperative Relaying Networks

We propose in this paper, a distributed optimal relay selection scheme for cooperative wireless networks to improve the performance of multimedia transmissions, while taking into account application layer quality of service (QoS), i.e., multimedia distortion. We formulate the cooperative relaying network as a stochastic bandit system. Moreover, the adaptive modulation and coding (AMC) strategy at the physical layer and the intra-refreshing rate at the application layer are jointly considered from a cross-layer design perspective. The objective is to minimize multimedia distortion, increase spectral efficiency, as well as prolong the average network lifetime. The optimal relay selection policy has an indexability property that dramatically reduces the on-line computation and implementation complexity. Simulation results are presented to show the effectiveness of the proposed scheme.