在時間與頻率選擇的時變通道上會造成在OFDM(orthogonal frequency division multiplexing)系統上每個載波的頻率失去其正交性(orthogonality)，進而造成載波間交互的干擾(Inter-Carrier Interference, ICI)。有很多方法提出來為了抑制ICI，但是它們的計算量過於複雜尤其對於較長的符元長度時。

　　在分析ICI發生的原因進而引導我們提出抑制ICI的方法基於低複雜度的(Minimum Mean Square Error)等化器可以有效的實現由於不需要有反矩陣的計算或者信號對稱設計可以大大的減少由於ICI所造成衰竭系統的效能。

　　經由電腦的模擬從位元錯誤率可以得到有效的抑制ICI的產生且具有較低的複雜性在時變多路徑衰竭通道上。

　Time variations of doubly-selective channels lead to the loss of orthogonality among subcarriers, resulting in inter-carrier interference (ICI) in orthogonal frequency division multiplexing (OFDM) systems. Many schemes have been proposed to suppress ICI, but they are of hight complex , especially for large block lengths.

　An analysis of the ICI leads us to propose an ICI cancellation scheme in this thesis based on low-complexity Minimum Mean Square Error (MMSE) equalization without matrix inversion. We also propose an ICI self-cancellation scheme based on the symmetry design of signals. Both of our proposed scheme can effectively reduce the ICI effects. Computer simulation results further validate the effectiveness of our proposed schemes.

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