具不完美通道狀態資訊的放大前送中繼通訊系統

Amplify-and-Forward Relay Communication Systems with Imperfect Channel State Information

林大洲(Ta-Chou Lin)

指導教授 ： 易志孝

淡江大學/工學院/電機工程學系碩士班/碩士(2011年)

https://doi.org/10.6846/TKU.2011.00990

摘要

對於同調調變下放大前送中繼通訊系統，在目的地節點的接收機欲執行最大比例結合時，需要知道通道狀態資訊和所有分集鏈路的等效雜訊變異數。在本論文中，我們將設計一個線性最小均方誤差估計器來估測放大前送中繼網路中，由來源節點，經中繼節點，至目的地節點(source-relay-destination, SRD)鏈路的等效雜訊變異數。為了使中繼節點及目的地節點的估計工作能更方便執行，在來源節點的訊框中我們採用導航符號輔助調變結構。我們研究的結果顯示SRD鏈路的等效雜訊變異數之最小均方誤差並不必然會隨著訊雜比增加而降低。此外，SRD鏈路的等效雜訊變異數估計誤差將產生訊雜比不匹配的問題，而造成位元錯誤率的上升。

關鍵字

通道估測 ； 合作式通訊系統 ； 中繼站傳輸

並列摘要

For amplify-and-forward (AF) relay communication systems with coherent modulation, the receiver at the destination node requires the channel state information and noise variances of all diversity links to perform maximal ratio combining. In this thesis, we design a linear minimum mean square error (LMMSE) estimator to estimate the equivalent noise variance of the source-relay-destination (SRD) link in AF relay networks. Pilot symbol assisted modulation is employed at the transmitter to facilitate the estimation task at the relay and destination nodes. Our results show the LMMSE of the noise variance of the SRD link dose not necessarily decrease as the signal-to-noise ratio (SNR) increases. Moreover, the estimation error of SRD link noise variance results in SNR mismatch problem which can degrade bit-error-rate performance of AF relay networks significantly.

並列關鍵字

channel estimation ； cooperative communication systems ； relay-based transmission

參考文獻

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