在多細胞OFDMA系統中，為了提高頻譜使用效率，系統分配子載波通常採用頻率再利用因子=1的設計方法，因而造成細胞間產生嚴重的互干擾。針對此問題，本論文提出了一個多細胞OFDMA系統下行鏈路的有效降低細胞間互干擾演算法。 所提演算法圖形理論及結合子載波選擇機制，將子載波分配給通道增益好且低互干擾的用戶有效地降低細胞間互干擾的問題。演算法中還針對不符合服務品質的用戶去做補償的動作以達到服務品質保證。論文最後以系統模擬比較提出的演算法和其他文獻方法的性能表現。

In order to increase spectrum efficiency, the radio resource management(RRM) with frequency reuse factor=1 is usually adopted the multi-cell OFDMA systems. Such a frequency allocation strategy will result in severe mutual interferences in the multi-cell system. In this thesis, we propose an effective algorithm to mitigate the mutual interferences for the multi-cell OFDMA downlink system. The proposed algorithm combines graph theory with subcarriers selection scheme to reduce the mutual interferences among cells. In the selection scheme, the subcarriers are assigned to the mobile users which have better channel gain and lower mutual interferences. The algorithm further compensates the mobile users which do not get enough resource to meet the requirement of quality of service. Numerical results show that the proposed algorithm can reach better frequency reuse utility than the algorithms proposed in literature.

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