臺灣博碩士論文加值系統

在移動下的無線通訊環境中，能否正確估測隨時間變動的通道資
訊，往往影響接收機性能的好壞。首先，在參照IEEE 802.11p
標準之下，將指標位置循環位移用以追蹤通道變化量的通道估測
方法，並探討綜合LDPC code 及多天線環境下的性能分析；第二
，本文提出一種Turbo Receiver 的架構，搭配EM 演算法和低密
度同位元檢查碼，藉由不斷地循環解碼與通道資訊更新，性能可
以大幅提昇。

In the mobile wireless communication environment, whether
could accurately estimate the varying channel information or not often influence the performance of the receiver. First, in reference to IEEE 802.11p, we proposed an efficient method of channel estimation which cyclicly shifts the pilots for tracking the channel variation. Besides, LDPC code and MISO are considered for DSRC environment. Second, we proposed a turbo receiver architecture which iteratively estimate channel variation and decoding by using so-called EM and SPA. performance can be much improved in mobile environment.

書名頁 i
論文口試委員審定書 ii
授權書 iii
中文摘要 iv
英文摘要 v
致謝 vi
目錄 vii
表目錄 iv
圖目錄 x

第一章 序論 1
1.1 引言 1
1.2 研究動機及目的 1
1.3 本篇論文架構 2
第二章 DSRC 與MISO OFDM 技術簡介 3
2.1 OFDM 技術簡介 3
2.1.1 OFDM 系統架構 4
2.1.2 OFDM 特性 4
2.1.3 OFDM 的保護區間 6
2.2 使用空時編碼於2x1 OFDM 系統 7
2.2.1 Alamouti Space-Time Block Code 7
2.3 DSRC 規格簡介 9
2.3.1 DSRC 使用頻帶與傳輸速率 10
2.3.2 系統效能需求 11
2.3.3 系統名詞 11
2.4 無線通道描述 12
2.4.1 通道衰減和多路徑干擾 12
2.4.2 多路徑通道的穩態特性 14
2.4.3 都普勒偏移 16
2.4.4 車對車通訊之通道模型 17
2.4.5 通道模擬方法 18
2.4.6 使用IDFT 方法建立通道 19
2.4.7 內插點數計算 20
2.4.8 使用TDL 建立多路徑模型 21
2.5 通道估測系統簡介 22
2.5.1 指標擺放位置與數量 22

第三章 有效的通道估測方法 27
3.1 指標估測理念 27
3.2 通道相關性 27
3.3 平移指標訊號 29
3.4 有效指標擺放方法 30
3.5 多天線系統指標設計 33

第四章 LDPC 碼與EM 演算法介紹 35
4.1 LDPC 碼起源 35
4.1.1 LDPC 原理與架構 35
4.1.2 Tanner 圖 37
4.1.3 LDPC Eecoding 38
4.1.4 LDPC belief propagation decoding 38
4.1.5 Min-Sum 演算法 43
4.1.6 計算在雷瑞通道衰減下的LLR 44
4.2 EM 演算法介紹 46
4.3 結合通道估測與資訊解碼 48

第五章 系統模擬與參數介紹 54
5.1 自訂系統參數 54
5.2 模擬通道環境 55
5.3 模擬結果 56

第六章 結論與未來展望 67

參考文獻 68

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