Efficient resource allocation based on layered coding in multicast systems with QoS guarantee

In conventional multicast scheme (CMS), the total throughput of multicast group is constrained by the user with the worst channel quality. In order to overcome the limited throughput problem, a multicast scheduling was considered based on layered coding. A new subcarrier and bit allocation algorithm is exploited for targeting the maximum throughput of a whole multicast group while at the same time guaranteeing the quality of services (QoS) requirements of all users. The article proposed an optimal resource allocation algorithm in the downlink of OFDMA-based wireless multicast group. A two-phase suboptimal algorithm was proposed as well to reduce the computational complexity. Simulations show that the performance gap between the optimal algorithm and the proposed suboptimal algorithm is quite small. The proposed algorithm significantly outperforms CMS. Moreover, it obtains more throughput than Tian's algorithm.