Resource Allocation with Subcarrier Cooperation in OFDM-Based Wireless Multicast System

In this paper, we investigate resource allocation issue in OFDM-based wireless multicast system and joint subcarrier and power allocation scheme is proposed. The optimal solution of the combinable allocation has high computational complexity, so the solution is divided into two steps. In the first step, the subcarriers are allocated to the multicast services, and all the users that have subscribed to one service share the same subcarriers. In order to increase the system capacity, a subcarrier cooperation and user grouping method is proposed. To further lower the computational complexity, a simplified method is derived. In the second step, the water-filling method is adopted to get further capacity improvement. The simulation results show that the proposed scheme performs better than the existing schemes, and the proposed simplified scheme can get a similar performance. Besides, the resource allocation schemes with multi-dimension water-filling allocation notably outperform the schemes with equal power allocation.