Asymptotically Optimal Resource Allocation for Layered Video Multicast Streaming in OFDMA Systems

In this paper, the subcarrier and power allocation for video multicast services in wireless OFDMA systems is considered. To overcome the multicast capacity loss caused by the conventional multicast scheme where the rate of a subcarrier is determined by the worst channel user, the fine granularity scalability (FGS) video coding is exploited in the multicast system. The FGS decomposes the video contents into a base layer and an enhancement layer, and the enhancement layer streaming only has to be transmitted to part of the multicast users based on their channel conditions. The corresponding subcarrier and power allocation problem is formulated as a mixed binary integer programming problem. The goal is to maximize the system total throughput while satisfying the total power constraint and the minimum base layer transmission rate requirement constraints. Then we develop an asymptotically optimal resource allocation scheme based on the dual decomposition method to solve the resource allocation problem. Simulation results show that the algorithm we proposed can significantly improve the network´s multicast capacity compare with the available suboptimal schemes.