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    Title: PSO 和 DDE 演化計算於室內無線通訊之應用
    Other Titles: PSO and DDE Evolutionary Computing in Indoor Wireless Communication
    Authors: 丘建青
    Contributors: 淡江大學電機工程學系
    Keywords: 超寬頻通訊系統;粒子群演算法;動態差異型演化法;位元錯誤率;Ultra-Wideband Communication System;Particle Swarm Optimization;Dynamic Differential Evolution;Bit Error Rate
    Date: 2010
    Issue Date: 2011-07-06 13:57:11 (UTC+8)
    Abstract: 近年來由於超寬頻通信系統的短距離、低功率之寬頻傳輸特性,使其成為目前無線 通訊中的新寵。已有許多超寬頻通訊在室內傳輸的相關文獻已經被發表,其大多研究是 以模擬或量測方式找出影響通道的統計參數後,並分析在此通道統計模型下的系統傳輸 錯誤率。本研究的目標是希望利用天線場型的調整,使得系統傳輸位元錯誤率能夠降至 最低。其中的要件除了通訊系統的參數之外,還包括室內環境多路徑傳輸效應的影響, 因此要解決這樣的問題可以看成一種求解最佳化的問題。由於粒子群演算法 (Particle Swarm Optimization, PSO) 的好處是以以生物群體間互相依賴的特性所提出的粒子群 聚演算法,不僅藉由自我過去經驗增加搜尋多樣性,並以粒子群彼此經驗的交流,使得 每個粒子都能夠往最佳位置的路徑移動更快速且有效的搜尋到問題的最佳解。動態差異 型演化法 (Dynamic Differential Evolution, DDE) 的是以動態形式更新最佳的參數 向量(物種);因此本研究使用 PSO 和 DDE 作為最佳化的工具。和一般以天線場型為目 標函數所不同的地方是,本研究擬以降低室內通信傳輸位元錯誤率為目標函數,再利用 PSO 與 DDE 作最佳化的調整,尋找出滿足最低傳輸位元錯誤率時的天線場型,此種場 型最能滿足室內無線通訊的需求。 本研究首先利用射線追蹤法計算出任意給定室內環境之脈衝響應,根據已知的天線 陣列以及考慮具同步電路的脈衝無線電超寬頻通訊系統,利用 PSO 與 DDE 做最佳化的 運算,尋找出使得傳輸位元錯誤率降至最低時的天線輻射場型以及系統的效能分析。並 且將此結果應用在室內無線區域的通訊上。希望藉由模擬結果,透過 PSO 與 DDE 分別 地調整天線陣列中每一個天線元件的信號饋入線長度,期望能在 3GHz-7GHz 合成出具 有指向性的輻射場型。此一研究目的指向性輻射場型能提供以下優點。(1) 在接收端能 有效地接收到每根天線所幅射出的能量,並進而提高接收端的訊雜比。(2) 此指向性輻 射場型能有效地減少多路徑效應的發生,使得信號在通道中傳輸的延遲擴散降低。 (3) 可大幅降低位元錯誤率,提高通訊品質。
    A new ultra wideband circular antenna array (UCAA) combining particle swarm optimization (PSO) and dynamic differential evolution (DDE) algorithm to minimize the bit error rate (BER) is proposed. Channels of virtual reality, which are corresponded with wireless personal area networks (WPAN), such as digital home and digital office etc. will be built by principles of ray-tracing techniques. Performance characterizations of ultra-wideband communication systems over channels of virtual reality are investigated. The ultra wideband (UWB) impulse responses of the indoor channel for any transmitter-receiver location are computed by SBR/Image techniques, inverse fast Fourier transform and Hermitian processing. By using the impulse response of multipath channel, the performance of the binary pulse amplitude modulation (B-PAM) impulse radio (IR) UWB system with circular antenna array can be calculated. Based on the topography of the antenna and the BER formula, the array pattern synthesis problem can be reformulated into an optimization problem and solved by the PSO and DDE algorithm. The PSO and DDE is used to regulate the antenna feed length of each array element to minimize the BER performance of the communication system. The novelties of our approach is not only choosing BER as the object function instead of sidelobe level of the antenna pattern, but also consider the antenna feed length effect of each array element. The strong point of the PSO and DDE algorithm is that it can find out the solution even if the performance index cannot be formulated by simple equations. Simulation was performed by UWB circular antenna array. Each array element is UWB antenna with omnidirectional radiation pattern within the 3 - 7GHz frequency band. Finally, optimal algorithm for UWB communication systems will be proposed tested.
    Appears in Collections:[電機工程學系暨研究所] 研究報告

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