極化碼是目前唯一能夠被嚴格證明可以達到Shannon極限的錯誤更正碼，而空間調變是一次只使用一根天線傳送訊號的多天線技術，可藉由選擇傳送天線多傳額外的資料位元。相差編碼的空間調變可以在接收端做非同調檢測，避免了傳送導頻(pilot)訊號所造成的頻寬浪費。 在本論文中，我們將極化碼應用於理想同調的空間調變、傳送導頻訊號的空間調變及相差空間調變，並比較它們錯誤效能。發現當傳輸速率相近時，相差空間調變錯誤率會優於導頻訊號的空間調變。由於原先相差空間調變檢測器複雜度太高，我們以硬式輸出的低複雜度檢測器概念為基礎，提出低複雜度軟式輸出檢測器方法。它針對天線位元及調變位元使用不同數學式子檢測，能大幅降低執行時間及複雜度，並與原先對數最大後驗機率法檢測有相近的錯誤率。 ;Polar coding is currently the only error correction code that can be strictly proven to achieve Shannon’s limit. Spatial modulation is a multi-antenna technique that uses only one antenna to transmit signals at a time. By selecting the transmitting antenna, additional data bits can be transmitted. Differential spatial modulation can do non-coherent detection at receiver, so it can avoid pilot overhead. In this thesis, we apply polar codes to ideal coherent spatial modulation, pilot-based coherent spatial modulation and differential spatial modulation, and compare their error rate. It can be found that when the data rates are similar, differential spatial modulation has better error rate than pilot-based coherent spatial modulation. Because the original log-MAP detector of differential spatial modulation is very complicated, based on a low-complexity hard-output maximum-likelihood detector, so we propose a low-complexity soft-output detector for differential spatial modulation. The purposed demodulator uses different equations for antenna bit’s and modulation bit’s. This method can nearly achieve the error rate with the original log-MAP detector, and the execution time is greatly reduced.
