本篇論文主要探討Quadrature Amplitude Modulation方式下，盲蔽式相位抓取的演算法效能，包含Histogram Algorithm (HA)、Modified Histogram Algorithm (MHA)、Maximum Likelihood (ML)、4th power-law和modified 4th power-law演算法比較。除此之外，由於無線通訊的日漸發展，於是在通道加入無線通訊的通道衰減情況(fading channel)，討論各演算法的效能。
研究信號在差分編碼以及QAM調變後，經過Additive White Gaussian Noise(AWGN)、phase offset以及fading channel後，利用ML、4th power-law、modified 4th power-law、HA 和MHA來找出phase offset。電腦模擬結果顯示在fading channel下，沒有直視路徑時，所有演算法效能都不佳，直視路徑能量越強時，效能越接近只有AWGN的情況。

In this thesis, the blind phase estimator algorithms are studied, including Histogram Algorithm (HA), Modified Histogram Algorithm (MHA), Maximum Likelihood (ML), 4th power-law and modified 4th power-law to compare their performance under quadrature amplitude modulation and additive white gaussian noise(AWGN) channel. Owing to the development of wireless communication, I used the fading channel of wireless communication and studied the performance of all algorithms again.
After differential encoding and quadrature amplitude modulation, signals enter additive white gaussian noise(AWGN), constant phase offset and fading channel. At receiver, I use the above estimator to find the phase offset. If there is not line of sight under fading channel, all estimators performance are not good from simulation results, if there is a strong line of sight, all estimators performance are good and approximate to the AWGN channel.

第一章 簡介 1
1.1 研究動機 1
1.2 論文簡介 1
1.3 論文架構 2
第二章 系統架構模型 3
2.1 QAM差分編碼的基本架構 4
2.1.1 差分編碼幾何意義 4
2.1.2 差分編碼數學式 6
2.2 對映(MAPPING) 6
2.3 通道(CHANNEL) 8
2.4 演算法介紹 8
2.4.1最大概似法(Maximum Likelihood (ML)) 8
2.4.2 4th Power-Law 9
2.4.3 Modified 4th Power-Law (reduced-constellation power-law (RCPL)) 10
2.4.4 Histogram Algorithm(HA) 10
2.4.5 Modified Histogram Algorithm(MHA) 12
第三章 衰減效應(FADING) 14
第四章 模擬結果 17
4.1各演算法在通道情況不同時的效能(SNR對RMSE作圖) 17
4.1.1 ML演算法 17
4.1.2 4th Power-Law 18
4.1.3 Modified 4th Power-Law (reduced-constellation power-law (RCPL)) 19
4.1.4 Histogram Algorithm 20
4.1.5 Modified Histogram Algorithm 21
4.2不同的通道情況，各演算法效能比較(SNR對RMSE作圖) 22
4.2.1 通道情況為AWGN和有phase offset 22
4.2.2通道情況為AWGN，有phase offset以及fading K=0(即不具有直視路徑) 25
4.2.3 通道情況為AWGN，有phase offset以及fading K=256(具有直視路徑) 28
4.3 L對各演算法效能之影響 31
4.3.1在128QAM以及SNR為25dB，AWGN通道 31
4.3.2在256QAM以及SNR為30dB，AWGN通道 33
第五章 結論 34
第六章 參考文獻 37

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