正交分頻多工（OFDM）技術為DVB-T所採用的核心技術。此系統運用了多載波間正交特性以達到高頻譜效益。而藉由前置循環字首（Cyclic prefix）及多載波之特性以達到消除符碼間干擾（ISI, Inter-symbol Interference）及抵抗多重路徑干擾；在高速移動環境下，DVB-T訊號經過時變的通道，接收到的訊號會有都普勒擴展(Doppler Spread)的現象，破壞了子載波間的正交性並引起載波間干擾(ICI)，會隨著移動速度上升而導致系統性能下降。為了克服高速移動所引起的載波間干擾(ICI)，本論文將前人方法加以改良，介紹了一套適合高速移動接收的載波間干擾消除。 本論文參考DVB-T系統，並且進一步的修改使其更合適於高速移動下的環境。運用ICI估測與消除，並比較了幾種不同ICI消除方法(Traditional 、ICI cancellation、Taylor series-like)。再利用這些消除方法結合ML演算法，針對受到ICI干擾的部分、SIR(signal to ICI Ratio)較低的部分，進行搜索，降低其錯誤率。 OFDM is a nucleus system of DVB-T. This system successfully eliminated the ISI effect and multi-path interference by using multi-carriers and inserting cyclic-prefix. In high-mobility environment, DVB-T signals pass the time-varying channel, and a loss of sub-carrier orthogonality due to Doppler spread of received signals leads to inter-carrier interference (ICI).This ICI effect degrades the maximum allowed velocity of reception. For eliminating this ICI effect due to high-mobility reception, this thesis modifies other’s methods and introduces a method about channel estimation and equalization, which is suitable high-mobility reception. This thesis refers to the DVB-T standard, and further makes it suitability for high mobility environment. By using ICI cancellation, and comparing three different scheme (Traditional, iterative ICI cancellation, and Taylor series-like) for channel and ICI estimation. In addition, we aim at low SIR ratio part which is influenced by ICI to add ML detection, which can improve the performance and reduce bit error rate.
