The throughput of conventional multicast transmission in wireless systems is limited by the user with the worst channel quality in the multicast service group. The subcarrier allocation for multicast services in multicarrier systems is a feasible solution to overcome the capacity limitation by exploiting the frequency diversity among subcarriers. However, most of the current subcarrier allocation algorithms are limited to unicast services. In this paper, we propose an optimal subcarrier allocation algorithm for multicast services with Quality of Services (QoS) guarantees. A low-complexity suboptimal algorithm is also proposed, which includes three steps: Conservative Allocation, Greedy Step and Iterative Enhancement. Simulation results show that the proposed algorithms significantly outperform the conventional multicast transmission scheme while at the same time guaranteeing the minimum data rates of all users. Moreover, simulation results also show that the performance difference between the optimal and suboptimal algorithms is small.
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