本文針對應用分散式時空方塊編碼(distributed space time block code)的放大再傳送(amplified-and-forward)合作式通訊 (cooperative relay network)系統，討論通道估計對系統的影響。在訊號傳送的過程中，訊源端(source)先將訊號傳送到中繼端(relay)，中繼端再將收到的訊號做編碼並傳送給目的端(destination)。在同調式的時空編碼系統中，目的端需要通道的資訊來做同調偵測(coherent detection)，因此，我們討論了兩種領航訊號(pilot)放置的方式來估計從訊源端到目的端的等效通道 (combined channel)，其中一種，TDM-SS，是在訊源端利用時分多路復用( Time Division Multiplexing)的方式，並在中繼端利用疊加(superimposed)的方式來傳送領航訊號;而另一種，SS-SS，則是在訊源端和中繼端皆利用疊加的方式來傳送領航訊號。在 TDM-SS這個方法裡，訊源端利用時分多路復用的方式來傳送領航訊號，而中繼端則將收到的領航訊號和之後收到的資料訊號(data)利用疊加的方式來傳送給目的端。而在SS-SS這個方法中，訊源端則利用疊加的方式來傳送領航訊號跟資料訊號；中繼端在收到訊號後會先將領航訊號和資料訊號的部份分開，接著再一次將兩者疊加後傳送給目的端。此外，我們還有找出最佳的領航訊號跟資料訊號之功率分配方式來最小化系統中訊號傳送的錯誤率。
在模擬分析的結果裡，相較於TDM-SS，由於SS-SS對於訊源端到中繼端之間的通道傳送了更多的領航訊號，因此有著更準確的通道估計並在資料訊號傳送時有較低的錯誤率。接著我們也將傳統的TDM-TDM 方法，也就是在訊源端和中繼端都利用時分多路復用的方式來傳送領航訊號，納入比較，可以觀察到當通道變動的速度不快時，TDM-TDM的方法即對通道有著準確的估計並有著良好的系統效能；而當通道變動快速時，則需要使用TDM-SS和SS-SS的方法來做通道的估計以達到較好的系統效能。

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