臺灣博碩士論文加值系統

在多重輸入多重輸出(multiple-input-multiple-output, MIMO) 系統中，使用高效
率錯誤更正碼經由位元交織(interleaver)再映射(mapper)以及接收端的迭代解調與解
碼(iterative demodulation and decoding, IDD) 架構，能夠使系統達到接近MIMO通道極
限的錯誤率表現，因此成為近年來非常重要的通訊技術。在此架構下，接收端之偵測器
可以接收來自解碼器回傳的外部資訊以產生系統所需的軟性(soft) 輸出。一般而言，迭
代式後驗機率演算法(maximum a-posteriori probability, MAP) 為典型的偵測器，其擁
有極佳的系統效能，但是相對地也有極高的運算複雜度。本篇論文中，我們結合迭代式
後驗機率演算法和最小均方誤差-平行式干擾消除(minimum mean squared error parallel
interfernce cancellation, MMSE-PIC) 的技術來改善多重輸入多重輸出的軟性偵測器。從
模擬結果可以得知，我們所提出的演算法在迭代解調解碼系統中能夠得到比最小均方誤
差-平行式干擾消除偵測器更低的錯誤率表現。

Iterative detection and decoding (IDD) for multiple-input-multiple-output communication
systems has drawn great research interests lately as it can achieve near-capacity
performance of the MIMO channel. While the maximum a-posteriori probability (MAP)
detector can achieve the optimal performance, the required complexity is often prohibitive
for practical implementation. In order to reduce the computational complexity in IDD,
the minimum-mean-squared-error parallel interference cancellation (MMSE-PIC) detector
has been proposed. The MMSE-PIC detector has the advantage of much lower computational
complexity compared to the MAP detector but the error rate performance is
much worse.
In this thesis, we propose an improved MMSE-PIC detector by combining the MAP
and MMSE-PIC detection. Simulation results show that the proposed detection scheme
can achieve better error rate performance comparing to the MMSE-PIC detection while
the computational complexity is still lower than that of the MAP detection.

1 序論1
1.1 研究動機與目的. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 章節概要. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 捲積碼系統4
2.1 捲積碼介紹. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 搭配和積演算法加上因子圖之捲積碼編碼與解碼. . . . . . . . . . . . . . 6
2.2.1 和積演算法與因子圖介紹. . . . . . . . . . . . . . . . . . . . . . 7
2.2.2 捲積碼編碼器. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.3 捲積碼解碼器. . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3 MIMO多天線系統20
3.1 MIMO多天線系統介紹. . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.2 MIMO系統架構模型. . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.3 MIMO偵測器. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.3.1 迭代式後驗機率偵測器. . . . . . . . . . . . . . . . . . . . . . . 25
3.3.2 最小均方誤差-平行式干擾消除偵測器. . . . . . . . . . . . . . . 27
4 本論文所提出之改良式MIMO迭代偵測器30
4.1 使用的MIMO迭代偵測器系統架構模型. . . . . . . . . . . . . . . . . . 31
4.2 改良式MIMO迭代偵測器. . . . . . . . . . . . . . . . . . . . . . . . . . 33
5 電腦模擬與效能分析40
5.1 迭代式後驗機率與最小均方誤差-平行式干擾消除偵測器之模擬結果與錯
誤率分析. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.2 提出之兩種改良式MIMO迭代偵測器之模擬結果與錯誤率分析. . . . . . 43
5.3 各種MIMO偵測器之模擬結果與錯誤率分析. . . . . . . . . . . . . . . . 45
5.3.1 各種MIMO偵測器之模擬結果與錯誤率分析. . . . . . . . . . . . 47
5.4 複雜度分析比較. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5.4.1 迭代式後驗機率偵測器與最小均方誤差偵測器之複雜度分析比較. 50
5.4.2 改良式MIMO迭代偵測器之複雜度分析比較. . . . . . . . . . . . 52
5.4.3 各種MIMO偵測器在還沒有迭代時之複雜度分析比較. . . . . . . 54
5.4.4 各種MIMO偵測器已經迭代兩次後之複雜度分析比較. . . . . . . 55
6 結論56
Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

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