Abstract
一個經由多重路徑衰褪通道傳送的訊號將因為通道的不理想效應使得接收器所收到的訊號難以解調偵測到正確的資訊。在這篇論文中, 我們將設計一個包含前置處理器, 估測器, 後置處理器以及偵測器的重建式超取樣接收器。在這重建式接收器的架構下, 前置處理器能抽出接收到的訊號中的充份統計量, 估測器則能透過前置處理器得到的充份統計量來估測訊號的衰褪增益並將估測的值傳給後置處理器做重建或補嘗的工作。最後將這重建後的訊號送給偵測器作解調偵測的工作。在這樣的重建式架構下, 我們把超取樣的技術應用到前置處理器上。希望透過這樣的處理能得到更多關於衰褪通道的訊息使得估測器能對通道增益作更準確的估測, 若是超取樣的取樣速度夠快則接收器對於通道的多重路徑效應的解晰度會增加。換言之也就是以寬頻的技術作另一種應用。在超取樣的應用下對於後置處理器也將因為有較多的取樣而得到較好的重建訊號。在這篇論文中, 我們將在第一章中介紹一些過去對於多重路徑衰褪通道所設計的接收器。在第二章中將討論多重路徑衰褪通道的特性。第三章中將針對超取樣技術對接收器的影響作較深入的討論。第四章將介紹我們所設計的超取樣接收器。第五章將對我們所設計的接收器作理論上的性能分析。在第六章中我們設計一個模擬程式模擬我們所設計的接收器。最後在第七章中對整個設計作一個結論。A signal transmitted through a multipath fading channel willbe distroied by the nonideal effects of the channels. It isdifficult for the receiver to detect the received signalscorrectly. In this thesis, we will introduce areconstructive over- sampling receiver structure consist of apreproce- ssor, a estimator, a postprocessor and a detector. Inthis reconstructive receiver structure, the pr- eprocessor willextract the sufficient statistics of the channels and theestimator will use these sufficient ststistics to estimate thefading gains of the channel. The postprocessor will reconstructor compensate the received signal by the estimated channelgains and the detector can detect the sig- nal infomations bythe reconstructive signals. In this receiver structure we tryto implement the o- versampling techinques in thepreprocessor. After applying oversampling on the preprocessor,The re- ceiver will extract more sufficient statistics fr- omthe fading chennls. If the oversampling rate is fast enoughthe resolution of the delay paths of the multipath fadingchannel caused by multipath effect will increase. In the otherword, it is an- other wind-band technique implementation. Inthis thesis, we will introduce some early works about thereceivers for multipath fading channels in ch- apter 1. Inchapter 2, we will introduce the char- acteristics of themultipath fading channels. In chapter 3, the influences forimplementing oversa- mpling techniques in the receiver will bediscuss- ed. In chapter 4, we will design a practical over-sampling receiver structure. We will derive a bit errorprobability upper bound by doing the perfor- mance analysis ofthat practical receiver. in cha- pter 5 and design a programsimulator of the prac- tical receiver and show somesimulation results. We give a conclusion about thisoversampling rece- iver in chapter 7.