單載波分頻多重存取(SC-FDMA)技術利用離散傅立葉轉換(DFT)作為預編碼採用正交分頻多工存取(OFDMA)的方式，也是第三代合作夥伴計劃(3GPP)提出的長期演進技術(LTE) 上行鏈路的標準。離散傅立葉轉換(DFT)作為預編碼的方式使得單載波分頻多重存取(SC-FDMA)系統擁有低的包絡波動(envelope fluctuations)並且比正交分頻多工存取(OFDMA)擁有較低的峰均值功率比(PAPR)。在無線通訊系統中擁有較低的功率峰值比(PAPR)是非常重要的，尤其是手持式的通訊系統裝置。然而，傳統的空頻區塊編碼(SFBC)使用在多輸入多輸出(MIMO)系統時置換了傳輸訊號的頻譜分量，導致單載波分頻多重存取(SC-FDMA)系統失去了低峰均值功率比(PAPR)特性。在本篇論文中，我們分析空頻區塊編碼(SFBC)中的排列、共軛與負號，對峰均值功率比(PAPR)的影響。根據分析結果，我們提出了設計方式去修正低峰均值功率比(PAPR)的空頻區塊編碼(SFBC)設計於單載波分頻多重存取(SC-FDMA)系統。模擬結果顯示，與傳統的空頻區塊編碼(SFBC)相比在錯誤率(BLER)性能有些微的下降，但我們所提出的設計方案在峰均值功率比(PAPR)的部分，在QPSK與16-QAM的調變下分別降低2dB與1.5dB。

Single Carrier Frequency Division Multiple Access (SC-FDMA), which utilizes Discrete Fourier Transform (DFT) as a pre-coder of Orthogonal Frequency Division Multiple Access (OFDMA), has been adopted as the standard for the uplink access scheme in Third Generation Partnership Project Long Term Evolution (3GPP-LTE). The DFT pre-coder makes SC-FDMA restoring the low envelope fluctuations of single-carrier (SC) systems and consequently provides a lower Peak to Average Power Ratio (PAPR) than OFDMA. The lower PAPR is a very important concern for wireless communication systems, hand-held devices especially. However, conventional Space-Frequency Block Coding (SFBC) used in Multiple-input Multiple-Output (MIMO) systems permutes the spectral components of the transmitted signal and causes SC-FDMA losing the low PAPR property. In this thesis, I analyze the arrangement and complex conjugate of the Space-Frequency Block Coding (SFBC) effect on the PAPR. According to the results of the analysis, I propose a modified low PAPR SFBC scheme for SC-FDMA systems. Simulation results show that with a slight degradation in the Bit Block Error Rate (BLER) performance our proposed scheme can benefit PAPR reduction around 2 dB for Quadrature Phase Shift Keying (QPSK) modulation and 1.5 dB for 16-Quadrature Amplitude Modulation (16-QAM) comparing with conventional SFBC, respectively.

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