臺灣大學: 電信工程學研究所陳光禎黃紀霖Huang, Chi-LinChi-LinHuang2013-03-272018-07-052013-03-272018-07-052010http://ntur.lib.ntu.edu.tw//handle/246246/253086摘要 近年來，正交分頻多工已經漸漸成為一項在無線網路中熱門的空中接口技術。因為具有高度彈性的配置子載波上的資源還有決定何種調變和編碼技術等特性，正交分頻多工技術已經被很多無線通信標準所制定採用。然而，雖然正交分頻多工技術有著前述顯著的特色，但是還它還是很受到時間和頻率偏移的影響。 LTE-Advanced是一項實體層技術採用正交分頻多工的無線行動蜂巢網路上的新科技，在本論文中主要著重於探討其中的一項載波聚合的新技術。在最近所有探討載波聚合技術的文獻中，大多把焦點放在媒體接取控制層或者更上層的部分做探討，而在實體層探討載波聚合的技術則是相當稀少的，所以，本論文想把焦點著重在載波聚合技術底下來研究正交分頻多工系統實體層同步的問題。我們所根據的是一個相當直覺的概念，就是在載波聚合技術底下藉由倚靠多出來的載波所帶的資訊應該能幫助我們讓信號的同步估測變得更準確。 在本論文中，我們推導出了在載波聚合技術底下以循環字首為主和以前置信號為主的兩種正交分頻多工同步演算法。依據模擬的結果顯示，我們所推導出在載波聚合技術下的兩種演算法所估測同步參數準確度都會比沒有採取載波聚合技術下的同步演算法較好。再則，在載波聚合技術底下以循環字首為主的演算法所多獲得的準確量會比以前置信號為主的同步演算法來更為顯著。Abstract In recently years, orthogonal frequency division multiplexing (OFDM) has become a popular technique in air interface of wireless communication. With high flexibility to subcarrier allocation, modulation and coding scheme, many wireless communication standards has adopted. However, although OFDM has above significant features, it is still sensitive to the effect of timing and frequency error. LTE-Advanced is a new coming mobile cellular communication technology whose physical layer technique uses OFDM. One new technical component of LTE-Advanced is carrier aggregation which is our main concern in this thesis. Recently, most studies about carrier aggregation focus on MAC or upper layer, and there is rare study on physical layer under carrier aggregation. In this thesis, we want to study the OFDM physical layer synchronization problem with carrier aggregation and to see how effect of carrier aggregation is on OFDM synchronization. An intuitive concept is that, with carrier aggregation, more component carriers mean that we have more extra information to solve synchronization problem which is better than one without carrier aggregation. In this thesis, we derived CP-based and Preamble-based method in single RF chain and multiple RF chains under carrier aggregation. According to the simulation results, the synchronization algorithm we derived can really do better than one without carrier aggregation. Furthermore, the performance improvement of CP-based method with carrier aggregation is more remarkable than improvement of Preamble-based method.33693071 bytesapplication/pdfen-US正交分頻多工同步3GPP LTE-Advanced載波聚合最大概似估計法時間捕獲頻率捕獲OFDM synchronizationCarrier AggregationMaximum Likelihood (ML) EstimationTiming acquisitionFrequency acquisitionthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/253086/1/ntu-99-R97942094-1.pdf