臺灣博碩士論文加值系統

正交分頻多工 (orthogonal frequency division multiplexing, OFDM) 技術是一種流行的無線傳輸技術。雖然已經在許多研究中被廣泛討論，OFDM技術仍然有缺點，其中之一就是過高的峰均功率比值 (peak-to-average power ratio, PAPR) 的傳輸訊號。過高的PAPR會降低高功率放大器的效能，並增加類比／數位轉換器的複雜度。由於出現的可能性低，一般有效降低PAPR的技術會使用統計的方法。而在部分傳輸序列 (partial transmit sequence, PTS) 是採用一種方法用來減少在OFDM系統中過高的PAPR值。由於PTS技術是利用相位因子產生多個候選訊號，大量的計算都必須尋找在候選訊號中最小PAPR的訊號，並將被選取到的訊號當作要傳送的訊號。此外PTS不具有錯誤更正能力，以防止通道干擾。為了解決這些問題，本研究提出一種次佳化的技術只需要少量的計算就可以減少PAPR及具有錯誤更正能力。我們採用了一種單性生殖交配器的改良型基因演算法 (the improved genetic algorithm used the partheno-crossover operator, PCGA) 作為選擇機制，並結合區塊編碼調變 (block coded modulation, BCM) 碼的原則，讓該方法具有錯誤更正能力，且我們將延伸在正交相移鍵控 (quadrature phase shift keying, QPSK) 調變的OFDM系統中。

Orthogonal frequency division multiplexing (OFDM) is a popular transmission technique in wireless communication. Although already widely addressed in many studies, OFDM still has flaws, one of which is the occurrence of high peak-to-average power ratio (PAPR) in transmission signal. High PAPR reduces the efficiency of high power amplifiers and increases the complexity of analog-to-digital converters. The partial transmit sequence (PTS) technique is one method adopted to reduce high PAPR in OFDM systems. With little data loss, this effective technique in PAPR reduction is generally categorized as a statistical method. However, as PTS utilizes phase factors to generate multiple candidate signals, large amounts of calculation and time are required to search the candidate signal with the minimal PAPR, which will then be adopted as the final transmission signal. In addition, PTS does not have error correction capabilities to prevent channel interference. To address these issues, this study proposes a suboptimal technique for PAPR reduction that requires less computation and possesses error correction capabilities. Our method employs a genetic algorithm with a partheno-crossover operator (PCGA) as the PTS signal selection mechanism. In conjunction with block coded modulation (BCM) codes to rectify the fault of no error correction capability, our technique can be applied in OFDM systems with quadrature phase shift keying (QPSK).

目錄
摘要 I
Abstract II
致謝 III
目錄 IV
表目錄 VI
圖目錄 VII
第一章 緒論 1
1.1 研究動機與目的 1
1.2 章節概述 2
第二章 OFDM與降低PAPR的方法 4
2.1 正交分頻多工系統 4
2.2 降低峰均功率比值技術 8
2.3 降低PAPR的技術 10
2.3.1 削減法 10
2.3.2 部份傳輸序列 11
2.3.3 選擇性映射 14
2.3.4 基因演算法結合部份傳輸序列 16
2.3.5 PCGA-PTS 20
第三章 線性區塊碼 23
3.1 區塊碼 25
3.2 里德米勒碼 30
第四章 BCMGAPTS&BCMPCGAPTS模擬結果 33
4.1 BCMGAPTS-QPSK 33
4.2 BCMPCGAPTS-QPSK 39
4.3 模擬結果 40
第五章 結論 54
參考文獻 55


表目錄
表4.1 BCMGAPTS和BCMPCGAPTS參數設定 38
表4.2在10^(-4)最高之PAPR值(單位：dB) 53

圖目錄
圖2.1正交分頻多工系統傳送和接收簡易區塊 4
圖2.2循環字首 5
圖2.3單載波傳輸示意圖 7
圖2.4多載波傳示意圖 7
圖2.5 部份傳輸序列系統架構圖 13
圖2.6 子區塊劃分方式(a)(b)(c) 13
圖2.7 選擇性映射系統架構圖 14
圖2.8選擇性映射效能 16
圖2.9輪盤式選擇示意圖 17
圖2.10基因演算法結合部份傳輸序列之基因演算法流程圖 19
圖2.11雙點交配示意圖 20
圖2.12單點交配示意圖 20
圖2.13 PCGA-PTS之基因演算法流程圖 21
圖3.1資料編碼示意圖 23
圖3.2區塊碼示意圖 24
圖3.3迴旋碼示意圖 24
圖3.4 區塊編碼過程示意圖 25
圖4.1 QPSK星座圖 33
圖4.2 BCM-GA-PTS系統方塊圖 37
圖4.3 BCM-GA-PTS之基因演算法流程圖 38
圖4.4 單性交配機制 39
圖4.5 N=128,M=16,P=100,RM(1,7),RM(2,7),Cm=1.0,Pm=0.05之BCMGA-PTS-QPSK-OFDM系統且劃分方式為鄰近劃分，在不同的G之下 41
圖4.6 N=256,M=16,P=100,RM(1,8),RM(2,8),Cm=1.0,Pm=0.05之BCMGA-PTS-QPSK-OFDM系統且劃分方式為鄰近劃分，在不同的G之下 42
圖4.7 N=128,M=16,P=100,RM(1,7),RM(2,7),Pm=0.05之BCMPCGA-PTS-QPSK-OFDM系統且劃分方式為鄰近劃分，在不同的G之下 43
圖4.8 N=256,M=16,P=100,RM(1,8),RM(2,8),Pm=0.05之BCMPCGA-PTS-QPSK-OFDM系統且劃分方式為鄰近劃分，在不同的G之下 44
圖4.9 N=128,M=32,P=100,RM(1,7),RM(2,7),Pm=0.05之BCMGA-PTS-QPSK-OFDM系統且劃分方式為隨機劃分，在不同的G之下 45
圖4.10 N=256,M=32,P=100,RM(1,8),RM(2,8),Pm=0.05之BCMGA-PTS-QPSK-OFDM系統且劃分方式為隨機劃分，在不同的G之下 46
圖4.11 N=256,M=32,P=100,RM(1,8),RM(2,8),Pm=0.05之BCMPCGA-PTS-QPSK-OFDM系統且劃分方式為隨機劃分，在不同的G之下 47
圖4.12 N=128,M=16,P=100,G=20,RM(1,7),RM(2,7),Cm=1.0,Pm=0.05之QPSK-OFDM系統且劃分方式為鄰近劃分，在不同的方法之下比較 48
圖4.13 N=256,M=32,P=100,RM(1,8),RM(2,8),Cm=1.0,Pm=0.05之QPSK-OFDM系統且劃分方式為鄰近劃分，在不同的方法之下比較 49
圖4.14 N=256,M=32,P=100,RM(1,8),RM(2,8),Cm=1.0,Pm=0.05之QPSK-OFDM系統且劃分方式為鄰近劃分，在不同的方法之下比較 50
圖4.15 N=128,M=16,P=100,G=20,RM(1,7),RM(2,7),Cm=1.0,Pm=0.05之QPSK-OFDM系統，在BCMGA和BCMPCGA方法之下且劃分方式為鄰近劃分和隨機劃分比較 51
圖4.16 N=256,M=16,P=100,G=30,RM(1,8),RM(2,8),Cm=1.0,Pm=0.05之QPSK-OFDM系統，在BCMGA和BCMPCGA方法之下且劃分方式為鄰近劃分和隨機劃分比較 52

[1]IEEE 802.16d, Air interface for fixed broadband wireless access systems, IEEE 802.16, May 2004
[2]J. H. Wen, S. H. Lee, Y. F. Huang, and H. L. Hung, “A suboptimal PTS algorithm based on particle swarm optimization technique for PAPR reduction in OFDM systems,” EURASIP Journal on Wireless Communic- ations and Networking, vol. 2008, Article in Press, ID 601346, May 2008
[3]T. Jiang and Y. Y. Wu, "An overview: peak-to-average power ratio reduction techniques for OFDM Signals", IEEE Trans. Broadcast., vol. 54, no. 2, pp. 257–268, June 2008.
[4]Yang, L., Chen, R.S., Siu, Y.M. and Soo K.K. ," PAPR reduction of an OFDM signal by use of PTS with low computational complexity", IEEE Broadcast Technology Society in Communication, Networking and Broadcasting., vol. 54, no. 1, pp. 83-86, 2006.
[5]Cimini, L.J., Jr., Sollenberger and N.R., "Peak-to-average power ratio reduction of an OFDM signal using partial transmit sequences", IEEE Communications Letters, vol. 4, no. 3, pp. 86 - 88, 2000.
[6]Yang, L., Soo, K.K., Siu, Y.M. and Li, S.Q.," A low complexity selected mapping scheme by use of time domain sequence superposition technique for PAPR reduction in OFDM system", IEEE Broadcast Technology Society in Communication, Networking and Broadcasting., vol. 54, no. 4, pp. 821-824, 2008.
[7]Chin-Liang Wang and Yuan Ouyang, " Low-complexity selected mapping schemes for peak-to-average power ratio reduction in OFDM systems", IEEE Transactions on Signal Processing, vol. 53, no. 12, pp. 4652 - 4660, 2005.
[8]S. S. Kim, M. J. Kim, and T. A. Gull- iver, "PAPR Reduction of OFDM Signals Using Genetic Algorithm PTS Technique," IEICE Trans. Commun., vol. E91–B, no.4, pp. 1194–1197, Apr. 2008.
[9]溫志宏等著，“正交分頻多重進接技術”， 滄海書局，2007年
[10]陳後守、邱茂清、王忠炫和吳昭明，”錯誤更正碼”大放異彩書局，2007年
[11]X.Gu, S. Baek and S. Park, "PAPR reduction of OFDM signal using an efficient SLM technique "Advanced Communication Technology (ICACT), 2010 The 12th International Conference, vol. 1, pp.324 – 328, 2010.
[12]S. Yang and Y. Shin, "Partitioned-SLM Scheme with Low Complexity for PAPR Reduction of OFDM Signals" IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications, vol. 1, pp. 1 - 5, 2010.
[13]Y. Zhang, Q. Ni, H. H. Chen, and Y. Song, "An Intelligent Genetic Algorithm for PAPR Reduction in a Multi-Carrier CDMA Wireless System, " in Proc. IEEE Wireless Communications and Mobile Computing Conference, 2008, pp. 1052–1057, Aug. 2008.
[14]H. Liang, Y.R. Chen, Y.F. Huang, C. H. Cheng, "A modified genetic algorithm PTS technique for PAPR reduction in OFDM systems," Communications, 2009. APCC 2009. 15th Asia-Pacific Conference, 2009 , pp. 182 – 185, 2009.
[15]Lan-Xun Wang, Kang Yang and Bin Xu, "Using the union algorithm of SLM and PTS to reduce PAPR in OFDM system," Computing, Communication, Control, and Management, 2009. CCCM 2009. ISECS International Colloquium on vol. 3 pp. 475 - 477, 2009.
[16]D. J. Jin and J. Y. Zhang, "A new crossover operator for Improving Ability of Global Searching, " in Proc. IEEE Machine Learning and Cybernetics, 2007, vol. 4, pp. 2328 - 2332, Aug. 2007.
[17]H. Liang, Z. Lin, H. Chen, and C.Y. Yang, "A modified genetic algorithm PTS technique with error correction for PAPR reduction in OFDM systems", Information Theory and its Applications (ISITA) pp. 1050 – 1053, 2010.
[18]H. Liang, K.C. Chung; H.S. Chen and Y.-F. Huang, "A modified constellation extension scheme with low complexity for PAPR reduction in OFDM systems", in Proc. of the 19th Annual Wireless and Optical Communications Conference, pp. 1 - 4, 2010.
[19]H. Liang, P. H. Kao, K. C. Chung and K. F. Zhang, " Combine Block Coded Modulation Codes with M-PTS for Peak-to-Average Power Ratio Reduction in OFDM Systems," in Proc. International Conference on Advanced Information Technologies, April 2011.
[20]梁新潁、陳彥儒、鍾國珍, ”具低運算量之改良型部分傳輸序列技術”, accepted in International Journal of Advanced Information Technologies (IJAIT). vol. 5, no. 1, pp. 58 - 72, June. 2011.
[21]林豐澤，“演化式計算計算上篇：演化演算法的三種理論模式”，智慧科技與應用統計學報。
[22]林豐澤，“演化式計算計算下篇：演化演算法的三種應用實例”，智慧科技與應用統計學報。