為了得到更高的資料傳輸速率需要更高的頻寬，因此在第三代合作夥伴計劃(3GPP)的長期演進進階版(LTE-A)中，提出了載波聚合(Carrier Aggregation)技術，利用聚合長期演進技術(LTE)的載波提升頻寬，達到高資料傳輸速率的目的。由於單載波分頻多重存取(SC-FDMA)擁有低峰均功率比(PAPR)的特性，在長期演進技術及進階版(LTE/LTE-A)採用單載波分頻多重存取(SC-FDMA)技術為上行鏈路的方案，不過隨著聚合越多的載波，除了複雜度會升高之外，也會導致系統峰均功率比(PAPR)的上升，使得原本單載波分頻多重存取(SC-FDMA)擁有低峰均功率比(PAPR)的特性被打破。此外，在聚合相同頻寬系統下，不同的載波組合也會有不同的PAPR，因此在研究上，首先將原先只針對兩個分量載波的探討擴充在聚合4、5個分量載波總頻寬為60M、80M、以3個符元(兩個資料符元、一個參考符元)為最佳化區間，找出使用部分選擇映射法(PSLM)降低峰均功率比(PAPR)效能最好的分量載波(CCs)組合，接下來在最好的分量載波組合下，提供不同最佳化區間PAPR效能及複雜度的選擇，最後我們提出一個與部分選擇映射法(PSLM)法降低相同PAPR效能但是複雜度較低的方法。

In order to obtain higher data rates, require lager bandwidths. Thus, Third Generation Partnership Project Long Term Evolution Advanced (3GPP-LTE-A) proposed carrier aggregation (CA) technology to utilize aggregation of Long Term Evolution (LTE) carrier to enlarge the bandwidth and achieve high data rate. Since SC-FDMA has a low peak to average power ratio (PAPR) characteristic, it has been proposed for the 3GPP-LTE/LTE-A uplink scheme. However, aggregate more carriers not only increases complexity but also raises the PAPR, thus the inherent lower PAPR property of the SC-FDMA does not exist anymore. In addition, combinations of different carriers may have different PAPRs under the same bandwidth aggregation system. In this research, we extend previous analysis to first find out the best PAPR performance by using partial selected mapping (PSLM) scheme from different combinations of component carriers (CCs) in the total aggregated four or five CCs systems with bandwidth 60MHz and 80MHz using three symbol (two data symbol, one reference symbol) optimal interval. We then provide tradeoffs between PAPR and complexity depending on different selection of the optimal interval. Finally, we proposed a scheme to reduce the PAPR with the same performance of the PSLM scheme but it has a lower computational complexity.

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