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研究生:曾明鋒
研究生(外文):Ming-Fong Tseng
論文名稱:同步取樣時間調整機制
論文名稱(外文):Feedforward Adaptive Sampling Time Synchronization Technique
指導教授:黃啟光黃啟光引用關係
指導教授(外文):Chi-Kuang Hwang
學位類別:碩士
校院名稱:中華大學
系所名稱:電機工程學系碩士班
學門:工程學門
學類:電資工程學類
論文種類:學術論文
論文出版年:2006
畢業學年度:95
語文別:英文
論文頁數:40
外文關鍵詞:sampling time offset(ST0)adaptivetiming synchronization
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取樣時間偏移量(STO)的估測與調整方法是本論文的研究主題,利用四點跟兩點關係值來做檢測的方法將在論文當中做介紹,我們提出了一個新的方法可以使得STO能夠適應性的做調整,在這方法當中,有著對於Roll Off強健性和增強關係量大小值的優點,並且利用線性逼近跟卡門濾波器來近一步改善系統效能,在檢測STO時引入一個條件門檻用來降低誤判的機會,在最後的模擬結果當中,可以證明,我們所以提出新的調整機制,可以有效的降低改善取樣時間偏移量的問題。
This thesis concentrates on the sampling time offset (STO) estimation scheme that employs the correlation of the short symbols specified in the preamble field of 802.11a WLAN frame structure. A simple detection strategy that uses four values and two values of the correlation is introduced. We also present a new algorithm by which the STO can be adaptively adjusted symbol by symbol. The adaptive algorithm inherits robustness against the variation of roll off rate and can improve the magnitude of the desired four points of correlated sequence. To take advantage of the adaptive algorithm, a linear curve fitting that focuses on the vicinity of zero STO is proposed, and then a state space based on the linear curve fitting can be constructed for a smoothing Kalman filter. Additionally, a threshold that can improve the STO detection is proposed to cooperate with the filter. The mean of estimation error resulted from this new scheme has been simulated for AWGN channels and multipath environments. Performance characteristics of the STO estimation using the non-adaptive method and the adaptive mode are evaluated via numerical examples. Our results show that the proposed method can effectively reduce STO.
1.Introduction ................................................. 7

2.Sampling Time Offset Detection .............................. 10
2.1 System Model and Sampling Time Offset Detection ........... 10
2.2 Implementation Issue ...................................... 13
2.3 Estimation Performance .................................... 15

3. Adaptive Sampling Time Offset Synchronization Technique ... 17
3.1 Traditional Timing Recovery Methods ....................... 17
3.2 Adaptive STO Estimation Algorithm ......................... 19

4.Simulation and Discussion ................................... 25

5.Conclusions ................................................. 29
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