DFT-s-OFDM ( Discrete Fourier Transform-spread Orthogonal Frequency Division Multiplexing)離散傅立葉變換展開正交分頻多重技術是一種用於通信系統的調製技術。它 結合了離散傅立葉轉換(DFT)和正交分頻多工(OFDM)，具有較好的頻譜效率和抗多 徑衰退能力。然而DFT-s-OFDM系統的波形特性存在一些問題，例如峰均功率比(PAPR) 較高，會導致系統性能下降和功率放大器的非線性失真。為瞭解決這些問題，本研究針對 DFT-s-OFDM通信系統進行了波形特性的分析和PAPR降低方法的研究。首先對 DFT-s-OFDM訊號的頻譜進行了詳細分析，探討了其頻譜特性和幅度分佈。然後通過模擬 實驗和數學推導，驗證了系統的PAPR較高的問題，並分析了其原因。在PAPR降低方法的 研究中，本研究提出了一種基於部分傅立葉轉換(PFT)的技術。該方法通過將訊號分成 多個子訊號，並對每個子訊號進行PFT處理，從而減小了整體訊號的PAPR。同時，通過引 入合適的旋轉因數和相位調製技術，可以在降低PAPR的同時使用CCDF對OFDM、SLM、 PTS和DFT-s-OFDM進行性能評估可以提供有價值的洞察力，了解它們在減少PAPR、處理 高功率峰值和保持無線通訊系統所需的QoS方面的能力。通過分析CCDF曲線，我們可以確 定每種技術在減少信號失真和優化系統性能方面的效果。通過對DFT-s-OFDM通信系統的 波形特性和PAPR進行研究，本研究為系統的優化提供了重要的理論依據和實踐指導。該研 究的成果有望在高效率、高可靠性的通信系統設計中得到應用，並為未來無線通訊技術的 發展提供借鑒和參考。;Abstract DFT-s-OFDM (Discrete Fourier Transform-spread Orthogonal Frequency Division Multiplexing) is a modulation technique used in communication systems. It combines the advantages of Discrete Fourier Transform (DFT) and spread Orthogonal Frequency Division Multiplexing (OFDM), offering improved spectral efficiency and resistance to multipath fading. However, DFT-s-OFDM systems exhibit some waveform characteristic issues, such as high Peak-to-Average Power Ratio (PAPR), which can lead to performance degradation and non-linear distortion in power amplifiers. To address these issues, this research focuses on the analysis of waveform characteristics and the study of PAPR reduction methods for DFT-s-OFDM communication systems. Firstly, a detailed analysis of the spectral properties and amplitude distribution of DFT-s-OFDM signals is conducted. Through simulation experiments and mathematical derivations, the problem of high PAPR in the system is verified and analyzed. In the study of PAPR reduction methods, a technique based on Partial Fourier Transform (PFT) is proposed. This method divides the signal into multiple sub-signals and applies PFT processing to each sub-signal, thereby reducing the overall signal′s PAPR. By introducing appropriate rotation factors and phase modulation techniques, it is possible to reduce PAPR while maintaining low bit error rate performance. By investigating the waveform characteristics and PAPR of DFT-s-OFDM communication systems, this research provides important theoretical foundations and practical guidance for system optimization. The findings of this study are expected to be applied in the design of high-efficiency and high-reliability communication systems, while also serving as a reference for the future development of wireless communication technologies.
