臺灣博碩士論文加值系統

在高速時變通道環境下，需要時變的通道估測才能滿足性能需求，利用訓練符元(Training symbol)和引導載波(Pilot tones)的觀念和學長的時變通道曲線估測法(Curve-fitting method)結合，提出非對稱引導載波時變曲線估測法。為了簡化其運算複雜度利用兩段式時變曲線估測法，在相同的效能之下能有效降地至少50%的運算複雜度。從模擬結果中可看出，在使用相近的overhead情況下，不但能利用有效的資訊量準確估出通道響應，且在複雜度方面也有明顯地減少。

A modified time-varying channel estimation method for orthogonal frequency division multiplexing (OFDM) systems is presented. The presented method makes use of asymmetric training symbols in combination with high-order polynomial fitting, and can thus obtain precious estimation results even under very large normalized Doppler frequency. To further reduce the computation complexity of the present channel estimation method, a modified two-step channel estimation method is also proposed. The modified two-step channel estimation method can maintain the same estimation performance but with at least 50% reduction in computation complexity.

誌謝 I
中文摘要 II
英文摘要 III
目次 IV
圖目次 V
表目次 VIII

第一章 前言 1
第二章 正交分頻多工系統 3
2.1正交分頻多工系統介紹 3
2.2快速時變通道特性 8
2.3無線通道模型 14
第三章 OFDM系統在時變環境下之通道估測 19
3.1引導載波通道估測方法 19
3.2 Yasamin通道估測法介紹 24
3.3 Chen通道估測法介紹 28
第四章 對稱式雙訓練符元時變通道曲線估測法 32
4.1對稱訓練符元時變通道曲線估測法 33
4.2二段式對稱訓練符元時變通道曲線估測法 48
第五章 非對稱式引導載波時變通道曲線估測法 53
5.1非對稱引導載波時變通道曲線估測法 54
5.2二段式非對稱引導載波時變通道曲線估測法 75
第六章 結論82
參考文獻 83

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