在同調偵測下，用多層編碼的區塊編碼調變(BCM)是具有頻寬效益的編碼架構，而最近提出一個新的用於非同調偵測的區塊編碼調變架構，稱作非同調區塊編碼MPSK(noncoherent block coded MPSK , NBC- MPSK)。藉由這個架構，數種非同調區塊碼可以輕易的由選擇適當的成份碼獲得，由於最大相似解碼的複雜度極高，所以使用多階層解碼以做為NBC-MPSK實際上解碼時可行的方法。 多階層解碼一般使用以籬柵為基礎的維特比解碼法則。但在有些情況下，解碼會相當的複雜甚至不可能實現。A*解碼法目前已經被使用在線性區塊碼的最大相似解碼上，且減少了搜索路徑。在本篇論文中，我們利用A*解碼法的概念用在非同調區塊編碼調變上，在電腦模擬結果上也展現了令人滿意的效能以及大幅的降低複雜度。 For coherent detection, block coded modulation encoded by multilevel coding is a bandwidth efficient scheme. Recently, a novel block coded modulation scheme for noncoherent detection called noncoherent block coded MPSK (NBC- MPSK) is proposed. Many noncoherent block codes can be easily obtained by properly choosing binary linear block codes as the component codes. However, maximum-likelihood decoding is complicated, so using multilevel decoding is a practical way to decode NBC-MPSK. In general, the trellis-based Viterbi algorithm is directly perceived for multilevel decoding. However, it becomes prohibitively complex and impractical to implement in some situations. A* decoding algorithm has been used to implement maximum-likelihood decoding of linear block codes. Moreover, it reduces the searching edges. In this thesis, we apply A* algorithm to ML decoding for NBC-MPSK. The satisfactory error performance and substantially reducing complexity are showed by computer simulation.
