國立臺灣大學電信工程學研究所林茂昭2006-07-262018-07-052006-07-262018-07-052004-10-31http://ntur.lib.ntu.edu.tw//handle/246246/20293正交分頻多工調變系統近年來被廣泛的使 用。但此系統有一個主要的缺點是高峰均值比的發 生機率較大。我們提出二個渦輪碼的正交分頻多工 調變系統並且在選擇性映射的方法下來降低峰均 值功率比。我們的方法是利用最大長度碼作為測試 序列來增加降低峰均值比的能力。以造成數個擁有 不同的峰均值傳送符號後，選擇最小峰均值的符號 傳送。在選擇性映射中所需要的附帶消息位元直接 附加在資料訊號的尾端，與資料位元同時受到渦輪 碼的保護，因此不需要額外的更正能力給予附帶消 息位元保護。此外我們在渦輪編碼中使用數個不同 的錯開器可以不需要附帶消息位元以得到更佳之 錯誤率。另外我們考慮將其相異的檢查位元部份規 則性的打散於碼句中以增加選擇性，可得到峰均值 的壓制及外頻雜訊的控制。OFDM system has been popularly applied to the many communication systems. Its major disadvantage is the high probability of large peak-to-average power ratio. We propose a turbo coded OFDM system with PAPR reduction by using selective mapping based method. For the first design we apply several maximum length sequences to the message bits to increase the PAPR reduction capability. We then have several OFDM symbols with the same information and different PAPR values. Then, we choose the one with the smallest PAPR for transmission. The side information is attached at the back of data frame and protected by the turbo coding. There is no need of extra protection to the side information. We can get the satisfactory bit error rate performance at high SNR. For the second design, we use several distinct interleavers in the turbo encoder. In this way, the necessity of side information is eliminated. For both the first and the second designs we consider the effect of arranging the parity bits of turbo codewords.application/pdf206271 bytesapplication/pdfzh-TW國立臺灣大學電信工程學研究所正交分頻多工調變渦輪碼峰均值比最大長度碼OFDMturbo codepeak-to-average power ratiomaximum length sequencereporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/20293/1/922213E002075.pdf