在本篇論文中首先將探討Chase演算法並且比較這些演算法的特性和優缺點。因為當初Chase演算法是被設計用於使用二位元正相反訊號的傳輸架構上，這對於現今使用MPSK或QAM當作訊號星座集的編碼調變架構是不適合的。我們將Chase演算法推廣使其可以適用在任何使用振幅/相位星座集的傳輸架構上，並且定義了一個新的信心測度。信心測度表示一個接收訊號的可靠度。 多級解碼一般使用以籬柵為基礎的維特比解碼法則。但在有些情形下，解碼會非常的複雜甚至不可能實現。非同調區塊編碼MPSK就有這個問題存在。一個使用Chase演算法的多級解碼在這篇論文中將被探討。根據每一層元件碼的不同特性，我們可以使用不同的解碼法則來處理不同層級的解碼。如此一來，多級解碼的實現將會更加靈活並且容易被實現。 In this thesis, the Chase algorithms are studied and compared with each other. Since these algorithms are originally designed for binary antipodal signals, they are not appropriate for modern coded modulation schemes that utilize MPSK or QAM. We generalize the Chase algorithms for signals of any amplitude/phase modulated constellations and propose a new definition of confidence measurement. In general, the trellis-based Viterbi algorithm is directly perceived for multistage decoding. However, it becomes prohibitively complex and impractical to implement in some situations. This problem also occurs in NBC-MPSK modulation. Herein, a more flexible multistage decoding utilizing the Chase algorithms is proposed. Different algorithms could be employed for relative levels in accordance with the properties of component codes. Consequently, the performance of the multistage decoding is more ingenious and acceptable.
