Real-time multimedia will be among the most important applications in next generation mobile networks. However, the efficient delivery of these applications to guarantee Quality of Experience (QoE) to fixed and mobile users in multimedia-aware networks is still a research challenge. This paper proposes new approaches to keep voice and video applications with an acceptable quality level in mobile wireless networks with scarce resources and investigates the impact of different video coding parameters on the QoE of voice sessions and real video sequences. Simulation experiments were carried out in a mobile multimedia system to show the benefits of the proposed QoE optimizations, by analyzing well-known QoE objective and subjective metrics.