本論文在研究現今的4G無線通訊架構 ，並進一步地使用遞迴式偵測架構(IterativeDetection)，來提高接收端的接收效率。在行動上網與無線通訊的需求及普及率越來越高的情況下，對於有限的無線頻譜來說除了進行有效率的頻譜分配外，要進一步的最大化頻普利用率，於是使用multi-input multi-output(MIMO)技術，可使空間中多出數個獨立通道來使資料同時且並行的傳送，達到增加傳送與接收率的目標，再結合Orthogonal Frequency-Division Multiplexing(OFDM)調變技術，組合成現今的4G行動通訊中的MIMO-OFDM ，並且再使用EXIT charts來進一步的分析偵測演算法與通道解碼器的特性。以上述的背景為條件下，我們加入正交的預先編碼，Hadamard code。而我們把正交碼分別使用在時域上和頻域上來做展頻，稱之為二維展頻。使傳送的訊號不僅有MIMO並同時具備Spreading的效果，如果頻率展頻碼的維度越大的話，那麼頻率分集增益就越強，所以這就是近幾年來展頻通訊為什麼如此的發達，而本篇論文最主要的主題是探討在接收機在做解碼，如何去降低複雜度，並且又能達到最好的效能，又不會比傳統最大事後機率還來的差，這就是我們所想要的結果。

In this thesis, we worked on the architecture of 4G wireless communication system. We use the iterative detection and decoding algorithm to arise the efficiency of the receiver. Due to the increasing popularity and demand of wireless online and wireless communication, it becomes the main concern to find ways to efficiently distribute the limited spectrum, and further maximize the utility of spectrum. For this purpose, we use multi-input multi-output(MIMO) technology, which can add many independent channels for data to transmit parallelly and simultaneously. It can help us to reach our goal of improving the efficiency. Then we combine MIMO technology with Orthogonal Frequency-Division Multiplexing (OFDM) modulation technology to be MIMO-OFDM, which is the focus of 4G mobile communication. Furthermore, we use EXIT charts to analyze the behavior of detection and decoder. Base on these architecture, we add orthonormal precode, Hadamard matrix, to spread. It makes signals have both MIMO and spreading. The bigger the spreading size is, the higher the diversity gain will be. That is the reason why spreading transmission becomes so popular in these years. Therefore, this research is focused on how to reduce the complexity of detection and having better performance.

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