使用複合式符元重建法降低正交分頻多工之剪波雜訊

Clipping Noise Reduction for OFDM by Hybrid-Symbol-Reconstruction

卓立(Li Cho)

指導教授 ： 許超雲

大同大學/電機資訊學院/通訊工程研究所/碩士(2010年)

摘要

對於正交分頻多工系統遭受高峰均功率比的問題，剪波法是一個既簡單又有效率的方法。然而，剪波法所引發的帶內失真(in-band distortion)及帶外幅散(out-of-band radiation)降低了系統的效能。在本篇論文當中，我們提出了一個新的帕波氏(Papoulis-Gerchberg)疊代演算法之應用以降低剪波雜訊，然後使用決策輔助重建法(decision-aided reconstruction, DAR)及一些有用的傳輸規格特性進一步改善最後成為複合式符元重建法(hybrid-symbol-reconstruction, HSR)。而所提出的複合式符元重建法在本研究中是以IEEE 802.16d-2004 為範例。在我們的剪波模型中(剪波比率為4dB)，模擬結果顯示出其效能與無剪波的情況相較之下可以被還原在5 dB 的誤差以內而跟原始的PGA 相比不需要額外的計算複雜度。

關鍵字

剪波法 ； 帕波氏疊代演算法 ； 峰均功率比之降低

並列摘要

Clipping is a simple and efficient solution to orthogonal frequency division multiplexing (OFDM) systems suffered from high Peak-to-Average Power Ratio (PAPR). However, clipping induces a noise of in-band distortion and out-of-band radiation that degrades the system performance. In this thesis, we proposed a novel application of Papoulis-Gerchberg algorithm (PGA) for reducing the clipping noise, and improved it with decision-aided reconstruction (DAR) and useful specification characteristics to attain hybrid-symbol-reconstruction (HSR) ultimately. The proposed HSR is applied to IEEE 802.16d-2004 scenario as an example. In our clipping model (clipping ratio is 4 dB,) the simulation results show the performance can be recovered to within 5 dB of the non-clipped case without additional computation complexity relative to conventional PGA.

並列關鍵字

Clipping ； Papoulis-Gerchberg algorithm ； PAPR Reduction

參考文獻

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