- 學位論文
應用反覆偵測通道估測和法蘭克斯窗於陸規數位電視廣播之接收機
Applying ITD Based Channel Estimation and Franks Window in DMB-T Receiver
摘要
DMB-T數位電視廣播採用時域同步正交分頻多工(TDS-OFDM)調變技術，利用PN序列取代傳統的CP-OFDM系統的循環字首做為保護間隔，並同時作為系統同步與通道估測。因為信號在頻域上沒有導引信號，比典型CP-OFDM系統具有更高的頻譜效率。 本論文使用兩種通道模型，如COST 207 TU6和6 Path Hilly Terrain，分別為短、中的時間延遲用來驗證以及評估通道估測演算法。本論文模擬陸規數位電視信號，使用自己撰寫的程式進行收發機制。其中使用兩種通道估測演算法，一個為基本的通道估測演算法，另一個為推廣之通道估測演算法，然後運用以上兩種方法來評估不同的通道模型下之效能。 驗證結果得到，在6 Path Hilly Terrain通道下所推廣之通道估測演算法加上雜訊平均與法蘭克斯窗的效能，比常用之通道估測演算法還好。在COST 207 TU6通道下所推廣之通道估測演算法加上雜訊平均和推廣之通道估測演算法加上雜訊平均與法蘭克斯窗的效能相近，但比常用之通道估測演算法還好。
並列摘要
The digital multimedia broadcasting-terrestrial(DMB-T) adapt the time domain synchronization-orthogonal frequency division multiplexing(TDS-OFDM).Instead of cyclic prefix scheme in traditional CP-OFDM systems, PN sequence has been proposed for guard interval, system synchronization and channel estimation in DMB-T system. TDS-OFDM provides higher spectrum efficiency than CP-OFDM due to no pilot in the transmitted signal. In this thesis, we have two kinds of channel models, TU6 and 6 Path Hilly Terrain, which use different time delay to verify and evaluate. We use our Matlab code to simulate the transmitter and the receiver of DMB-T system. We use two kinds of channel estimation algorithm to verify and estimate the performance of channel estimation algorithm, one of them is basic channel estimation algorithm and the other is proposed channel estimation algorithm. Based on our experimental results, the performance of the proposed channel estimation algorithm which added noise reduction and Franks window in 6 Path Hilly Terrain channel is better than the basic channel estimation algorithm. In COST 207 TU6 Channel, the performance of the proposed channel estimation algorithm which added noise reduction is close the performance of the proposed channel estimation algorithm which added noise reduction and Franks window. But it is better than basic channel estimation algorithm.