臺灣博碩士論文加值系統

由於網際網路的盛行，多媒體時代的來臨，使用者對於電路頻寬的需求成倍數地快速成長，為滿足客戶的需求，能夠利用既有的雙絞線銅纜網路（Twisted-pair copper cable network），以提供成本低廉且高頻寬的傳輸能力之各種xDSL的技術乃應運而生。就台灣而言，ADSL的客戶數業已超過一百二十萬，且持續增加中，因此ADSL之效能已是眾所囑目的焦點所在。
由於各種xDSL設備同時在雙絞線銅纜網路上建置使用，使得其使用的頻譜部分會重疊，導致在同一條電纜中，各雙絞線彼此間產生串音效應，因而影響各種xDSL的效能。所以，本論文係針對在中華電信公司的銅纜網路上已普遍建置使用的HDSL與新一代即將建置使用的SHDSL所產生之串音效應對ADSL傳輸效能的影響進行分析比較。
由實驗模擬的結果可確知在50對雙絞線銅纜中，49對SHDSL干擾源對ADSL上行通道所產生之串音干擾，比CAP-HDSL小11.62 dB，比2B1Q-HDSL小1.15 dB，就ADSL的通道容量來加以比較，在SHDSL的串音干擾下與在CAP-HDSL的串音干擾下相比，其上行通道容量增加418 Kbps，下行通道容量減少893 Kbps，與在2B1Q-HDSL的串音干擾下相比，其上行通道容量增加27 Kbps，下行通道容量減少319 Kbps，故SHDSL可有效改善ADSL上行通道之串音干擾情況。同時，我們所提出雙絞線銅纜的頻譜劃分方式，能有效改善ADSL的上行通道容量至860 Kbps以上。

To comply with the requirement of customers, various technologies of xDSLs are developed. The technologies make use of the existed twisted-pair copper cable network to provide inexpensive services with a high capacity of transmission bandwidth. Because various facilities of xDSLs are applied simultaneously to the twisted-pair copper cable network, parts of their frequency spectrum overlap. It turns out that one twisted-pair wire generates a crosstalk on another wire in the same cable, which seriously breaks down the performance of xDSL.
Nowadays the number of Asymmetrical Digital Subscriber Line (ADSL) subscribers has been over one million in Taiwan and continues to increase. So, the objective of this thesis is to analyze and compare the effects of crosstalk from High-bit-rate Digital Subscriber Line (HDSL) and Single-pair High-speed Digital Subscriber Line (SHDSL) on the capacity of ADSL at the twisted-pair copper cable network of the Chunghwa Telecom Co., Ltd in Taiwan.
The power spectrum densities for various schemes are derived and the channel capacities are evaluated under the influences of HDSL and SHDSL. Numerical simulations are performed and the results are investigated. Based on the results of this work, we found that the upstream link of ADSL under the interference from 49 SHDSL disturbers has a capacity of 418 Kbps larger than that from Carrierless Amplitude Modulation/Phase Modulation HDSL (CAP- HDSL) disturbers.
Therefore, a scheme of frequency spectrum allocation is proposed for the twisted-pair copper cable to improve the channel capacity of ADSL. It can be shown that the upstream channel capacity can be increased upto 860 Kbps or above if our proposal is executed.

中文摘要-------------------------------------i
英文摘要-------------------------------------ii
誌謝-----------------------------------------iv
目錄-----------------------------------------v
表目錄---------------------------------------viii
圖目錄---------------------------------------ix
符號說明-------------------------------------xii
第一章簡介-----------------------------------1
第二章基本原理-------------------------------3
2.1PSD of xDSL-------------------------------3
2.1.1 ISDN與2B1Q-HDSL之PSD-------------------5
2.1.2 T1 Lines之PSD--------------------------15
2.1.3 CAP-HDSL之PSD--------------------------21
2.1.4 SHDSL之PSD-----------------------------28
2.1.5 離散多載波調變之ADSL下行通道之PSD------33
2.1.6 離散多載波調變之ADSL上行通道之PSD------37
2.2 雙絞線迴路之轉換函數---------------------39
2.3 雙絞線迴路之串音模型---------------------44
2.4 昂格爾近端串音模型與簡化的串音模型-------47
第三章傳輸通道容量分析-----------------------49
3.1 信號雜訊比-------------------------------49
3.2 近端及遠端串音下的信號雜訊比-------------50
3.3 通道容量---------------------------------51
3.4 近端及遠端串音下之通道容量---------------52
第四章數值模擬----------------------------55
4.1 CSA #6 Loop之轉換函數模擬----------------56
4.2 各種xDSL之PSD模擬------------------------57
4.3 各種xDSL之NEXT下ADSL的信號雜訊比模擬-----61
4.4 各種xDSL之FEXT下ADSL的信號雜訊比模擬-----73
4.5 各種xDSL之XTALK下ADSL的信號雜訊比模擬----76
4.6 各種xDSL之NEXT下ADSL的通道容量模擬-------79
4.7 各種xDSL之XTALK下ADSL的通道容量模擬------82
4.8 HDSL與SHDSL所產生之串音對ADSL的信號雜訊比差異模擬--85
4.9 HDSL與SHDSL所產生之串音對ADSL的通道容量差異模擬----86
4.10 頻譜劃分方式之xDSL的NEXT下ADSL通道容量模擬---------88
第五章結論-----------------------------------92
參考文獻-------------------------------------96
附錄ITU-T G.996.1區域迴路結構----------------98
[1] 北美地區測試迴路模型（North American Test Loops）-----------98
[2] 歐洲區域測試迴路模型（European Local Test Loops）-----------100

[1]Bernard Sklar, 2001, Digital Communications, 2nd edition, Bernard Goodwin, New Jersey.[2]Dr. Dennis J. Rauschmayer, 1999, ADSL/VDSL Principles, Macmillan Technical Publishing, Indianapolis.[3]ITU-T Recommendation G.996.1 draft, “Test Procedures for Digital Subscriber Line(DSL) Transceivers,” Geneva , Switzerland, October 1997.[4]Syed V. Ahamed, “Simulation Environments for the High-speed Digital Subscriber Line (HDSL),” in Proc. IEEE Int. Conf. Communications (ICC’93), Geneva, vol. 3, pp.1791—1796, 1993.[5]ITU-T Recommendation G.991.2 draft, “Single-Pair High-speed Digital Subscriber Line (SHDSL) Transceivers,” Antwerp, Belgium, June 2000.[6]ITU-T Recommendation G.992.1 draft, “Asymmetrical Digital Subscriber Line（ADSL）Transceiver,” Geneva, October 1998.[7]吳明義，1988，通信電纜構成種類及電氣特性，交通部電信訓練所高雄分所印行。[8]Walter Y. Chen & David L. Waring, “ADSL Noise Environment and Potential System Performance,” in Proc. IEEE Int. Conf. Communications (ICC’94), vol. 1, pp.451—455, 1994.[9]John W. Cook, Rob H. Kirkby, Martin G. Booth, Kevin T. Foster, Don E. A. Clarke, and Gavin Young, “The Noise and Crosstalk Environment for ADSL and VDSL Systems,” IEEE Communications Magazine, vol. 37, Issue 5, pp.73-78, May. 1999.[10]J. H. W. Unger, “NEXT Model for Line Code Studies,” Bell Communications Research Contribution, T1D1.3/85-244, Nov. 1985.[11]Marco Carbonelli, Domenico De Seta, Daniele Perucchini, and Lamberto Petrin, “Evaluation of Near-end Crosstalk Noise Affecting ADSL Systems,” in Proc. IEEE Int. Conf. Communications (ICCS’94), Singapore, vol. 2, pp.630—634, 1994.[12]I. Kalet and S. Shamai, “On the capacity of a twisted-wire pair: Gaussian model,” IEEE Trans. Commun., vol. 40, No. 2, pp.379-383, March 1990.[13]J. T. Aslanis and J. M. Cioffi, “Achievable information rates on digital subscriber loops: limiting information rates with crosstalk noise,” IEEE Trans. Commun., vol. 40, No. 2, pp.361-372, Feb. 1992. [14]Walter. Y. Chen, “Architecture and Performance Simulation of Single Pair HDSL,” in Proc. IEEE Int. Conf. Communications (ICC’96), vol. 3, pp.1421—1425, 1996.[15]George A. Zimmerman “Achievable rates vs. Operating Characteristics of Local Loop Transmission: HDSL, HDSL2, ADSL and VDSL,” IEEE Signals, Systems & Computers, vol. 1, pp.573—577, 1997.