時-空碼系統具有完整的通道訊息狀態(CSI)已被提出來，但在實際的通訊環境當中，為了獲得被傳送的訊號，接收端必須知道通道訊息狀態。因此，在論文中我們發展兩種時-空碼的通道估測技術。其中一種是使用時間-空間方塊碼去輔助通道估測，主要針對時間-空間籬柵碼和時間-空間方塊碼的結合與格碼調變和時間-空間方塊碼的結合；另一種為非使用時間-空間方塊碼去估測時間-空間籬柵碼的通道。
　　此外，一個修改過的PSP(Per-Survivor Processing)技術也提出來處理這些架構，在一個快速與慢速頻率非選擇性的雷瑞衰減通道(Rayleigh fading channels)裡，可以同時估測通道與檢測符號(symbol)。而且，一個重傳機制被使用來獲得更大頻譜效益，但是相對有一較差的系統效能。最後，提出一般的通道估測方法以供比較，其中這些引導位元(pilot symbol)是週期性的被傳送出去。
　　在效能分析方面，我們針對慢速(fdT=0.001)與快速(fdT=0.01)衰減的通道，考慮他們框錯誤率(FER)。除此之外，我們針對不同的重傳方式，考慮這些架構的效能。一個有趣的現象在於快速衰減通道的效能，當考慮不同的重傳機制，這些效能的結果都非常的接近。我們也計算系統的編碼速率(code rate)，以描述編碼速率與系統效能彼此間的取捨。

　　Some space-time coding (STC) systems have been proposed with perfect Channel State Information (CSI). In a practical communication environment, the receiver has toknow or estimate the true CSIs in order to recover the transmitted signal. Therefore, inthis thesis we propose two schemes of channel estimation for STC systems. The first scheme uses the Space-Time Block Coding (STBC) to assist in channel estimation. For this scheme we consider both the Space-Time Trellis Coding (STTC) and Trellis Coded Modulation (TCM), with STBC-assisted channel estimation based on per-Survivor Processing (PSP). Our second proposed scheme of STTC channel estimation is also based on PSP, without resorting to the STBC.
　　We propose a modified PSP algorithm to jointly estimate channel and detect symbols.This algorithm is suitable for slow/fast frequency non-selective fading channels. In addition, a re-sent mechanism is used to obtain higher spectral efficiency, though its performance is a little degraded. We also compare the performances of our proposed schemes with the general pilot-assisted method, where the pilot symbols are periodically
transmitted.
　　In the simulation and analysis, we consider FER (Frame Error Rate) for both slowly fading channels with fdT=0.001 and fast fading channels with fdT=0.01. Besides, we focus on different ways of re-sent and the corresponding performances for the above structures. We find that in fast fading channels, different ways of re-sent schemes result in close performances. We also analyze the code rate of systems and discuss the trade-off between system code rates and performances.

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