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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/9363


    Title: OFDM技術應用於LMDS系統在時變通道模型下之效能評估;Performance evaluation of an OFDM-based LMDS using time-variant channel models
    Authors: 陳宜德;Yi-De Chen
    Contributors: 電機工程研究所
    Keywords: OFDM;LMDS;LMDS;OFDM
    Date: 2002-05-29
    Issue Date: 2009-09-22 11:46:12 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: LMDS (Local Multi-point Distribution Service) 有釵h好處,例如:能提供寬頻的服務、架構建立較簡單、硬體設備花費較少等;而OFDM (Orthogonal Frequency Division Multiplexing) 對於ISI (Inter-symbol Interference) 、多路徑傳輸衰減有較大的抵抗能力。因此,本篇論文嘗試將兩者合併並加以模擬分析。 本篇論文首先設計傳送和接收端的模組,其中實體層的參數是參照IEEE 802.16所提供的標準[8]。通道模型是採用1999年在新加坡以LMDS為架構所測量而得的模型[6],再加上兩種通道預測方法去模擬比較其效能。 論文中的模擬結果顯示: (1) 在LMDS的環境裡,OFDM對於多路徑傳輸衰減的抵抗力較傳統PSK、QAM的系統強。 (2) OFDM技術應用於LMDS系統,加上通道預測確實可以再提高其效能。 Local multipoint distribution service (LMDS) has three advantages: 1) large bandwidth 2) lower installation cost 3) ease of deployment [6]. Orthogonal frequency division multiplexing (OFDM) can solve some questions in communication systems, for example: inter-symbol interference, multi-path fading and so on. This thesis combines the OFDM technique with the LMDS system to simulate the OFDM-based LMDS system under the time-variant channel, which modeled by the measurement in Singapore [6]. And we use the two channel estimation methods, which one is linear interpolation method; the other is a novel method proposed in [3], to combat the interference of multi-path components. The simulation results show that 1) the performance of the OFDM system is better than of the traditional modulation systems in multi-path channel in LMDS environment 2) the channel estimation using pilot sub-carriers can improve the performance in the OFDM system.
    Appears in Collections:[電機工程研究所] 博碩士論文

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