時空編碼與多路徑分集特論

Abstract

時空編碼是一種可以從多重天線系統中得到分集增益的編碼技術。它可以分成兩大類:時空區塊編碼和時空籬柵編碼。在[1]和[2]分別對這兩種編碼方式在平緩衰減通道中的情形有詳細的討論。在本論文中，我們結合時空編碼和MLSE演算法來處理因為頻率選擇性通道所造成的交互位元干擾，並且得到額外的多路徑分及增益來增進系統的效能。另外，我們提出了一種時空籬柵編碼的編碼方式，這種編碼可以和通道結合，在接收端做聯合解碼來增進效能。另ㄧ方面，將會把提出的演算法和其他相關的演算法做比較。最後，會使用模擬結果來驗證這個演算法的分集階數和效能。

Space-Time coding is a coding technique to achieve the diversity gain of multiple antennas system. Two popular space-time codes, space-time block code (STBC) and space-time trellis code (STTC), are investigated in [1] and [2] for flat fading channels without intersymbol interference. In this thesis, we extend space-time coding to frequency selective channels. We combine space-time coding with MLSE (Maximum Likelihood Sequence Estimator) algorithms to handle the intersymbol interference and exploit the multipath diversity gain of frequency selective channels. Furthermore we propose a new space-time trellis coding process that combines the coding with the channel effect, and achieve diversity gain by joint decoding at the receiver. On the other hand, we also compare the proposed algorithm with some related algorithm. Finally, simulation results will be presented to verify the diversity order and the performance of the proposed coding scheme.