近幾年來，正交分頻多工(Orthogonal Frequency Division Multiplexing, OFDM)訊號設計已經廣泛應用於許多不同類型的通訊系統中，像是WiMAX (IEEE 802.16e)、LTE (Long Term Evolution)與數位視訊廣播(Digital Video Broadcasting, DVB)。但是正交分頻多工技術訊號有著峰均功率比(Peak-to-Average Power Ratio, PAPR)過大的缺點，此缺點會增加類比與數位轉換的複雜度，並降低傳送端功率放大器的效能。
近幾年許多文獻討論了許多降低正交分頻多工技術訊號峰均功率比的方法，其中最受文獻討論的是PTS與SLM兩種方法，但皆需要傳送側訊息(side information)供接收端解回正確訊號。也有些文獻提出在不需要側訊息的條件下來討論降低峰均功率比，但接收端需採用複雜性高的ML演算法。本論文提出一種在不需要側訊息的條件下，可在接收端以結合通道估測方式解回訊號的線性相位SLM技術。為降低本技術在傳送端實作的複雜度，本論文亦提出低複雜度的電路實現設計。
模擬結果顯示，利用本論文提出的降低峰均功率比演算法，能比傳統方法擁有更好的降低PAPR效能，且接收端能在不需要側訊息情況下，成功解回傳送訊號。

Orthogonal frequency-division multiplexing (OFDM) signal design has been widely adopted in many wireless communication standards, such as WiMAX (IEEE 802.16e)、LTE (Long Term Evolution) and DVB (Digital Video Broadcasting). Although this signal design holds many advantages, it has a major drawback of high peak-to-average power ratio (PAPR), which increases the complexity of the D/A and A/D converter designs and reduces the power efficiency of the transmitter's power amplifier.
Many literatures have proposed solutions to solve the PAPR problem. Partial transmit sequences (PTS) and selected mapping technique (SLM) are two well-known algorithms to reduce PAPR. However, both schemes require side information to recover the signal at the receiver. Recently, solutions without side information were proposed, but they usually come along with maximum likelihood (ML) detection method with high complexity. In this paper, we propose a linear-phase SLM without side information, and the receiver can recover the information with the aid of channel estimation. In addition, we also proposed a low-complexity implementation design at the transmitter.
The simulation results show that our method has better performance of PAPR reduction compared with the conventional methods. Moreover, after reducing PAPR, it remains the same bit-error rate (BER) performance over the additive white Gaussian noise (AWGN) channel and fading channels without any side information.

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