Layered Video Resource Allocation in Mobile WiMAX Using Opportunistic Multicasting

We propose a resource allocation algorithm that provides enhanced QoS and efficiency for layered video multicast over mobile WiMAX. The application is characterized by groups of users acquiring popular video programs over a fading channel. To accommodate various bandwidth requirements and adaptive perceptual quality to different users, video streams are coded into base and enhancement layers using scalable video coding technology. Correspondingly, the optimization problems, which assign the most appropriate modulation schemes to provide best video quality to as many users, can be formulated using opportunistic multicasting concept. We maximize the minimum effective throughput across all users for mandatory (base) layer delivery through adapting modulation and coding schemes. At the same time, optional (enhancement) layers are allocated to maximize total utility. Thus the basic video quality can be efficiently guaranteed to all subscribers while making most out of limited resources on enhancement information. We further present an FEC rate adaptation scheme to approach theoretical performance. Favorable performance of the proposed algorithms is demonstrated by simulations utilizing realistic Mobile WiMAX parameters.