低密度同位元檢測 (LDPC) 編碼有相當高的傳輸速率，也能有相當好的性能表現，並且可以適用在釵h無線通訊系統中。傳統應用於多輸入多輸出的正交分頻多工 (MIMO-OFDM) 系統中的低密度同位元檢測編碼使用長度極長的編碼分散在數個 OFDM 符號傳送，這樣長度極長的編碼難以實現。在此論文中，我們由結構化的低密度同位元檢測編碼著手，並針對多輸入多輸出的正交分頻多工系統 (MIMO-OFDM system) 的環境提出一種具結構性的 LDPC 編碼設計方法，院使用固定映射的方式排列編碼字符，亦可拿到不低的多樣性增益 (Diversity gain)。編碼字符長度和天線個數與OFDM次通道個數有關，實作編碼的可行性較高。最後將所提出的設計方法應用於使用正交相位偏移編碼 (QPSK) 的多輸入多輸出的正交分頻多工系統，呈現其性能的模擬結果、與隨機設計的編碼，以及使用其它排列方式的編碼比較的模擬結果、以及在較少路徑的通道環境中的模擬結果。

This paper presents a new method for low density parity check (LDPC) coded multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems. The proposed method can be used to construct structured short-length LDPC codes using fixed approach to arrange codeword and providing high diversity gain. And its codeword length is associated with the number of transmit antenna and the number of subcarriers of OFDM system, such that it is practical. Conventional LDPC codes designing for MIMO-OFDM systems use random interleaver and lead to a high-complexity receiver, although long-length LDPC codes are well performed but impractical. Followed the proposed method, we construct structured LDPC codes, and compare with codes constructed according to other schemes, and show the performance simulated in fewer paths environment.

致謝............................................................................................................................... I
中文摘要...................................................................................................................... II
英文摘要..................................................................................................................... III
目錄............................................................................................................................. IV
第一章　序言 1
2.1 MIMO-OFDM 簡介 3
2.2 LDPC 簡介 4
2.3 先前研究 5
第三章　提出演算法 7
3.1 系統模型 7
3.1.1 通道模型 7
3.1.2 設計準則 8
3.2 設計方法 14
第四章　實驗模擬 17
4.1 實驗設計理念及模擬限制 17
4.2 系統方塊 18
4.2.1 頻空碼通道編碼單元 18
4.2.2 訊號映射單元 19
4.2.3 渦輪接收器 20
4.2.3.1 軟輸入軟輸出等化器單元 21
4.2.3.2 頻空碼通道解碼器單元 22
4.3模擬結果 23
4.3.1 不同檢測秩所建造之編碼的性能比較 23
4.3.2 在不同的通道環境中的性能表現比較 27
4.3.3 比較不同映射方式之編碼的性能比較 30
4.3.4 不同的通道環境中不同映射方式之性能比較 35
第五章　結論 38
第六章　參考文獻 39

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