相差編碼是一個在傳送端的傳統技術，它可以讓接收端做簡單的非同調檢測。另一方面，籬柵編碼調變是一種提供可靠數據傳輸的頻寬效益技術。在本論文中，我們在通道同調時間N為3個符號的情況下，考慮籬柵編碼調變加上相差編碼的設計。我們先做集合分割，再根據所得的各層最小距離做碼搜尋，並分析搜尋到的籬柵碼之最小非同調距離。會與通道同調時間N為2所搜尋到的籬柵碼比較，我們所搜尋到的籬柵碼皆有較大的最小非同調距離以及較佳之錯誤率模擬。除此之外，我們也修正同調距離的計算方式，所搜尋的籬柵碼在較多狀態個數時，會優於原本的籬柵編碼。;Differential encoding (DE) is a classical technique at the transmitter that allows simple noncoherent detection at the receiver. On the other hand, trellis-coded modulation is a bandwidth efficient technique which offers reliable data transmission. In this paper, we consider TCM with DE for channel phase coherence over N = 3 symbols. First we do partitioning. Based on the set partitioning, trellis codes are searched and their minimum distances are analyzed. They are compared with the codes searched for N = 2. For both minimum distance and simulation results, the obtained new codes outperform code for N=2. Besides, we propose a new coherent distance calculation method for trellis code searches. For large number of trellis states, Both minimum distance and simulation results outperform original codes.
