臺灣博碩士論文加值系統

於相鄰符元間干擾通道(inter-symbol interference
channel)下的傳統的編碼傳送架構，就在編碼符元間被打亂再送入相鄰符元間干擾通道之前，軟輸入/軟輸出(soft-in-soft-out)的非固有資訊傳送圖形(EXIT
chart)在相鄰符元間干擾通道的巨大等化離散通道裡面圖形是呈現徒峭的狀態。
在這篇論文之中，我們提出來的方法會平坦非固有資訊傳送圖形(EXIT
chart)接近水平於渦輪碼的非固有資訊傳送圖形(EXIT chart)
或者迴旋碼使之最佳化於可加性高斯白雜訊通道之中，設計一個傳送架構，就是表示使用交錯碼在第一個碼字以及第二個碼字互相交錯且相鄰排列，
使之交錯傳輸，並且此傳輸的方式一直連續的下去。因此，當同樣在可加性高斯白雜訊下的最佳通道碼被使用的時候，
建議的限值(threshold)和常用的系統比較之下會優於常用的系統。
使用這種方法，分析在非固有資訊傳送圖形中，我們可以發現，在這種傳送的交錯方法，於非固有資訊傳送圖形在表現上會和平常的方法比較之下會較平坦，利用這種平坦的特性，我們提出了利用渦輪碼，以及配合這篇論文所提出來的新奇渦輪等化系統(A novel turbo equalization scheme)，並且我們的星座圖使用GM法，在分析於接收端已知道通道的情況之下，利用此新奇渦輪等化系統配合渦輪碼之下，我們可預期的發現非固有資訊傳送圖形會有比平常系統平坦以及接近渦輪碼解調端的非固有資訊傳送圖形的狀態，故利用此方法，即可以在低訊雜比(SNR)，得到不錯的效能。

For a conventional coded transmission scheme
operating in an inter-symbol interference (ISI) channel in which the
coded symbols are interleaved before being sent to the ISI channel,
the extrinsic information transfer (EXIT) curve of a
soft-in-soft-out (SISO) equalizer is steep for large equivalent
discrete channel length of an ISI channel. In this paper, we propose
to flatten the equalizer EXIT curve to match the close-to-horizontal
EXIT curves of the turbo decoder or convolutional decoder optimized
for AWGN channels by designing a transmission scheme which is
implemented by first interleaving a codeword with two adjacent
codewords and then transmitting the interleaved codewords
sequentially. Hence, the thresholds of proposed system are better
than those of the conventional system when the same channel codes
optimized for AWGN channels are used.

1 Introduction 1
2 Bit-interleaved coded modulation with iterative decoding 3
2.1 System description . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 The concepts of the decision . . . . . . . . . . . . . . . . . . . . 4
2.2.1 Soft decision . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.2 Soft output of channel with LLR . . . . . . . . . . . . . 4
2.2.3 Convolutional codes . . . . . . . . . . . . . . . . . . . . 5
2.3 MAP estimation . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4 Algorithm of BCJR . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.5 Max-Log MAP Algorithm . . . . . . . . . . . . . . . . . . . . . 12
2.6 Correction function of the Log-MAP Algorithm . . . . . . . . . 13
2.7 Iterative decoding using soft feedback . . . . . . . . . . . . . . . 13
3 Reviews on MMSE based Turbo equalization 17
3.1 Transmission scheme . . . . . . . . . . . . . . . . . . . . . . . . 17
3.2 A Soft-Input Soft-Output APP Module for Iterative Decoding . 18
3.3 The optimal MMSE estimator . . . . . . . . . . . . . . . . . . . 21
3.4 Signal Constellation . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.5 Symbol a priori mean value and a variance . . . . . . . . . . . . 24
3.5.1 MMSE with sliding-window model . . . . . . . . . . . . 25
3.5.2 MMSE equalization . . . . . . . . . . . . . . . . . . . . 26
3.5.3 Symbol extrinsic of probability . . . . . . . . . . . . . . 27
3.6 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.7 Convergence analysis . . . . . . . . . . . . . . . . . . . . . . . . 30
4 A novel turbo equalization scheme for interference channels 36
4.1 Arrangement of symbols . . . . . . . . . . . . . . . . . . . . . . 36
4.2 System Description . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.3 Complexity of TEAC . . . . . . . . . . . . . . . . . . . . . . . . 41
4.4 Punctured TE using Turbo codes . . . . . . . . . . . . . . . . . 48
5 Conclusion 55

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