在一篇2005年的論文中，提出一種用於多天線正交分頻多工調變系統的非同調空頻碼。但由於它的解碼為一個碼字一個碼字測試，若頻段數目不少時，其複雜度太高。在本篇論文中，我們使用多階層解碼來修改此論文所提出的架構，先將所有頻段分成若干組，在每一個解碼階層，使用之前所解出的組及其對應收到訊號的資訊，來解一組，在傳送端，我們也調整功率來降低錯誤率。除此之外，我們也使用籬柵編碼來進一步改善錯誤效能。

In 2005, a noncoherent space-frequency coded MIMO-OFDM scheme was proposed. But its complexity is very high if the number of tones is not small. In this thesis, we modify this scheme by using multistage decoding. All tones are divided into several groups. In each decoding stage, one group is decoded with the information of previously decoded groups and the corresponding received signals. At the transmitter, the power is also adjusted for decreasing error rates. In addition, trellis coding is utilized for further enhancing the error performance.

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