時變通道環境下LTE上行鏈路系統中通道估測與等化之改善

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研究生：	呂孟祐 Meng-You Lu
論文名稱：	時變通道環境下LTE上行鏈路系統中通道估測與等化之改善 Improvement of Channel Estimation and Equalization for LTE Uplink System in Time-Varying Channel Environment
指導教授：	陳逸民 Yih-Min Chen
口試委員:
學位類別：	碩士 Master
系所名稱：	資訊電機學院 - 通訊工程學系 Department of Communication Engineering
論文出版年：	2012
畢業學年度：	101
語文別：	中文
論文頁數：	92
中文關鍵詞：	LTE上行鍊路傳輸系統、模型化通道估測、直接決策
外文關鍵詞：	LTE-Uplink, Model-Based Channel Estimation, Decision–Direct
相關次數：	點閱：11 下載：0
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Orthogonal frequency-division multiplexing (OFDM)是一種有效的技術，以應付在寬頻無線通訊的頻率選擇性衰弱通道。Single-carrier frequency-division multiple access(SC-FDMA)它是一種可以實現類似的性能，基本架構相同於OFDM。SC-FDMA是OFDM先經由預編碼運算，此運算是經由離散傅立葉轉換(DFT)完成，使用預編碼可以降低均峰比PAPR並且可以有效的功率使用且降低製造成本。但OFDM技術性能主要取決於通道的頻率響應(CFR)估測的準確性。大多數高性能的通道估測建立在利用其頻率響應上的通道統計特性。也是有一些實現較為簡單，基於模型的方法並且對於頻率響應的相關性依賴性較少，由SC-FDMA中的參考訊號可以得到完整的通道資訊，以利於基於模組(Model-Based)運算加上修改式直接決策方法，使通道估測相較於傳統方法有較好的性能。

Orthogonal frequency-division multiplexing (OFDM) is an effective technique to cope with frequency-selective fading channels in broadband wireless communications. Single-carrier frequency-division multiple access(SC-FDMA) is a technique which can achieve similar performance and essentially the same structure as OFDMA. SC-FDMA pre-codes its information-bearing symbols by discrete Fourier transform (DFT). This pre-coding operation can reduce PAPR and can benefit power efficiency and reduce manufacturing cost. The performance of OFDM technique depends mainly on the accuracy in channel frequency response (CFR) estimation. Most high performance channel estimation schemes exploit the correlation of the CFRs of subchannels which rely on the knowledge of channel statistics. There are also some Model-Based methods which are relatively simple in implementation and less dependent of the CFR correlation.In SC-FDMA we use reference signal can get the symbol complete channel information for Model-Based computy and Decision–Direct ,which have better performance compared to traditional methods.

授權書    i
論文指導教授推薦書    ii
論文口試委員審定書    iii
摘    要    iv
ABSTRACT    v
目  錄    vi
圖目錄    ix
表目錄    xii
第一章    緒論    1
1    研究動機與背景    1
2    章節提要    2
第二章    LTE上行鏈路簡介    3
1.1    正交分頻多工調變原理    3
1.2    保護區間(guard interval)與循環延展(cyclic extension)    8
1.3    OFDM系統架構    10
2    SC-FDMA與上行鏈路    11
2.1    單載波分頻多工簡介    12
2.2    子載波對映(subcarrier mapping)    13
3    LTE傳輸架構    15
3.1    訊框架構類型    15
3.2    時槽(slot)架構    18
4    領航訊號排列    20
4.2    塊狀領航碼 (Block-type Pilot)    22
5    LTE上行鏈路參考訊號    22
6    LTE上行鏈路參考訊號配置    25
第三章    通道模型與通道估與等化    27
1    通道模型    27
2    時變通道模型    29
    線性近似法    31
3    等效基頻訊號    35
4    可加性高斯白雜訊通道(AWGN Channel)    37
5    頻域上參考訊號符碼通道估測    40
5.1    最小平方近似法通道估測    42
5.2    多項式模型化(Model-Based)通道估測    44
6    頻域上資料符碼通道估測    47
6.1    塊狀通道估測    47
6.2    線性內外插通道估測    49
6.3    直接決策(Decision-Directed)通道估測    50
6.4    修改式直接決策    52
6.5    通道模組化修改式直接決策    55
7    通道等化(Equalization)    57
7.1    Zero forcing(ZF)等化器    57
7.2    MMSE等化器    58
8    模型化下MMSE修改式直接決策    59
第四章    電腦模擬與分析    60
1    系統與通道參數    60
2    等化器模擬    62
3    模型化通道估測參數模擬    64
4    模型化通道估測模擬    67
第五章    結論與未來展望    76
參考文獻    77

                                

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