使用時域頻域聯合通道估測之高效能地面數位影像廣播接收機設計

Abstract

數位影像廣播與傳統的類比影像廣播相比有許多的優點，如高畫質、省頻寬和抗干擾能力強等。而接收機設計的好壞決定了系統的效能高低。本篇論文的目的就是要設計一個高效能的地面數位影像廣播(DVB-T)接收機。 首先，我們建立一個地面數位影像廣播(DVB-T)系統的完整模擬平台，包括傳送機與接收機部份。接收機是由內部接收機與外部接收機構成，前者負責同步，後者則是做錯誤更正解碼。接著我們將重點放在設計高效能的通道估測法。因為傳統上在頻域做通道估測的方式效能並非最佳，故我們使用一種新開發的時域頻域聯合通道估測法來解決此一問題。模擬結果顯示，此通道估測法比起傳統的方法效能較高，特別對在延遲展延(delay spread)較大的通道下。

Compared with traditional analog video broadcast, digital video broadcast (DVB) has many advantages such as high definition, reduced bandwidth, and high interference immunity. However, the actual performance greatly depends on the receiver design. The purpose of this thesis is to design a high-performance DVB-T receiver. First, we built a complete platform for the DVB-T system, which includes the transmitter and the receiver. The receiver consists of the inner and outer receivers; the former conducts synchronization, and the later forward error decoding. Then, we focus on the design of the high-performance channel estimator. Conventional approaches for channel estimation is conducted in the frequency domain, and the performance is not optimal. We use a newly developed joint time-and-frequency- domain channel estimator to solve the problem. Simulations show that the channel estimator has better performance that conventional methods, specially when the channel delay spread is large.