第四代無線通訊的長期演進技術進階版(Long Term Evolution-Advanced, LTE-Advanced)系統裡，上行系統採用擁有低峰均值功率比(Peak to Average Power Ratio, PAPR)特性的單載波分頻多重存取(Single carrier Frequency Division Multiple Access, SC-FDMA)，並使用LTE-Advanced標準裡的載波聚合(Carrier Aggregation, CA)技術來提升傳輸頻寬，以達到更高的傳輸速率。本文將原有SC-FDMA架構中，有預編碼功能的離散傅利葉轉換(Discrete Fourier Transform, DFT)改以離散小波轉換(Discrete Wavelet Transform, DWT)的方式來進行預編碼，藉此來降低位元錯誤率(Bit Error Rate, BER)，此架構被稱作小波轉換之單載波分頻多重存取技術(Wavelet SC-FDMA, W-SC-FDMA)，並以此系統為基礎加上CA技術來改良，使整體傳輸效益更加提升。
然而使用CA技術時，PAPR會隨著聚合的分量載波個數越多而持續上升，因此破壞了SC-FDMA本身帶來的低PAPR優點，故在本論文所使用改良為DWT預編碼之SC-FDMA中使用部分選擇性映射(Partial Selected Mapping, PSLM)的技術來降低PAPR，並假設接收端用來還原訊號的側訊息(Side Information, SI)為完美估測。方法的模擬上，除了原先參考文獻中降低PAPR的方法外，本論文另外提出新的降低PAPR架構，針對DWT所產生的近似組成(Approximation Component)中加入PSLM，以達到降低運算複雜度和PAPR。
在本論文當中，除了會探討常規SC-FDMA與W-SC-FDMA於不同通道模型、不同聚合總頻寬的BER效能模擬，也會針對加入降低PAPR技術後PAPR的效能模擬，並討論結果之間的差異變化與總結。

LTE-Advanced proposed carrier aggregation techniques which utilizes aggregated multiple carriers to increase the bandwidth and achieve high data rate. In practice, LTE-Advanced uplink systems adopt single carrier frequency division multiple access (SC-FDMA) which has a low Peak to Average Power Ratio (PAPR) characteristic. In order to lower the bit error rate, we used the Discrete Wavelet Transform(DWT) to replace conventional Discrete Fourier Transform this precoding operation in SC-FDMA. The system we used which named Wavelet SC-FDMA(W-SC-FDMA). In this thesis, we proposed a new system structure let W-SC-FDMA with Carrier Aggregation.
However, not only the conventional SC-FDMA but also the W-SC-FDMA system’s low PAPR characteristic will lose as the number of aggregated carriers are increasing. Therefore, we adopt the Partial Selected Mapping (PSLM) technique to reduce PAPR and discussed how to design the PSLM in Wavelet Transform structure. PAPR will reduce by multiplying phase factor which represents as the Side Information (SI) at the receiver. The receiver must have received the side information in order to recover the signal’s phase but as the SI were transmitted in system would decrease data rate because of the extra SI data.
To avoid this situation, our structure adopts Physical Uplink Shared Channel (PUSCH), its time slot structure includes reference symbol which can be used for channel estimation. Therefore, we use the reference symbol to substitute the SI to achieve without directly sending SI. And we also use reference symbol’s characteristics to estimate the phase factor and recover the signal’s phase by estimated phase. In this thesis, we chose five kinds of phase estimate methods and discussed in imperfect channel estimation in order to observe what would change in BER. Furthermore, as previous section we mentioned the W-SC-FDMA system, the new system structure with CA and lower PAPR methods; we will simulate the BER performance of new structure in different channel models, equalizers, different aggregation bandwidth and different number of aggregated carriers. Further, we compared the PAPR’s variation in original and new structure.

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