臺灣博碩士論文加值系統

摘要


台灣高速鐵路即將在今年底通車,高鐵列車最大營運速度可達每小時300公里以上, 面對如此高速的環境,要能提供良好的行動通訊服務,無疑是各系統業者之一大挑戰。而GSM系統自1992年開始被廣泛的運用至今,提供給用戶語音、短訊及GPRS等服務功能；雖然目前在台灣的第三代行動通訊(3G)系統,各業者已正如火如荼的展開並積極的建置第三代行動電話基地台;但是根據調查,還是有百分之七十以上的民眾仍使用GSM系統,因3G客戶的使用習慣及各項服務的費率昂貴,而且3G網路的涵蓋尚未全面普及化。所以,以語音服務為主的GSM系統,因手機價格及通話費率比較便宜,且GSM既有之網路已建置綿密,因此仍然為目前國內現代行動通訊最主要的系統。

本文實際測試DCS-1800系統,在高速移動下對通訊品質的影響,並針對DCS-1800系統在台灣高速鐵路的環境下可能產生的問題採取因應的對策,並提出將基地台裝置於在車箱內的方式,而BTS與BSC在Abis介面以衛星傳輸連結,來解決當高鐵列車在高速移動下所產生的問題。 同時並對同步衛星的實際應用及可行性的評估分析下,若在無衛星路徑遮蔽、頻道干擾或特殊天候狀況下,以本文提出之架構可達到較佳的系統效能。本系統在Abis介面全部的Eb/No大約是13dB,在接收端的誤碼率小於 ,這顯示了從基地台透過同步衛星的連結到基地台控制中心的傳輸架構是可行的。

Abstract


Taiwan High Speed Rail will become operational at the end of this year, and the maximum operating speed of the train can reach up to 300 kilometers per hour. Therefore, there is no doubt to be a serious challenge for mobile wireless communications industry to maintain a reliable communication quality under high speed ambiance for commuter of the bullet train.
Global System for Mobile (GSM) has been widely adopted since 1992 and offers voicemail, instant message and GPRS functions. Although the vigorous construction of third generation mobile systems (3G) and its base stations are setting out like wildfire amongst the telecommunication corporation in nowadays Taiwan, according to studies, 70% of cellular phone users still use GSM systems since 3G has not been widely accepted because of higher fare rate and less-popularized network. The 3G network is still not prevalent on the island; people mainly use the voice service through GSM service because the rates are less expensive. Moreover, GSM has already set up a compact network on the island and it is therefore still the mainstream of nowadays mobile telecommunication system.
This thesis will test the DCS-1800(GSM-1800) under high speed conditions and to overcome the problems of the DCS-1800 in the Taiwan High Speed Rail ambiance. Foremost among these solutions is that the base station should be located on the train. We will connect BTS and BSC via the satellite communication under the Abis interface to solve the problems of connection under high speed rail conditions. At the same time, we must consider that using a geostationary satellite and the feasibilities to estimate the analysis. We have concluded the argument put forth in this thesis will demonstrate a framework that will provide the better system solution, if the satellite have no shielding, no inter-symbol interference and under the ideal weather conditions. The Abis interface overall Eb/No is about 13 dB and analysis results of the receiver signal bit error rate is less than which exhibits that transmission from BTS to BSC via GEO satellite is feasible on this framework.

Contents


Acknowledgement........................................................................................................I
摘要………………………………………………………………………………......II
Abstract……………………………………………………………………………..III
Contents……………………………………………………………………………...V
List of Figures……………………………………………………………………..VIII
Tables of Contents……………………………………………………………….....XI
Chapter 1 Introduction……………………………………………………………..1
1.1 Motivation………………………………………………………….1
1.2 Background………………………………………………………...2
1.2.1 High Speed Railway (HSR) in Taiwan………………………2
1.2.2 Evolution of Wireless Communication in High
Speed Railway……………………………………………… 2
1.3 DCS-1800 System………………………………………………….5
1.3.1 Overview of GSM System Standard………………………... 5
1.3.2 System Architecture and Interfaces………………………….5
1.3.3 Specification and Parameter…………………………………8
1.3.4 Radio Channels in GSM……………………………………..9
1.3.5 TDMA Structure and Throughputs…………………………12
1.4 Organization of Thesis……………………………………………13

Chapter 2 Effects of Fast Moving Mobile Station……………………………….14
2.1 Concept of Wireless Channel……………………………………..14
2.2 The Doppler Effect………………………………………………..15
2.2.1 The Doppler Shift…………………………………………...15
2.2.2 The Classical Doppler Spectrum……………………………17
2.2.3 Doppler Spread in the Time Domain….…………………….18
2.3 Multipath in the Frequency Domain………………………………21
2.3.1 Time Dispersion Parameter………………………………….21
2.3.2 Coherence Bandwidth (Bc)……………………………….…22
2.4 Types of Small-Scale Fading………………………………………..23
2.4.1 Fading Effects due to Multipath Time Delay Spread……….24
2.4.2 Fading Effects due to Doppler Spread……………………...25
2.5 Fading Distributions…………………………………………….…..27
2.5.1 Rayleigh Fading Distribution……………………………….27
2.5.2 Rician Fading Distribution………………………………….30
2.6 Techniques Used to Overcome Signal Fading…………………….. .31
2.6.1 Diversity Reception and Transmission……………………...31
2.6.2 Space–Time Codes………………………………………….32
2.6.3 Multiple-Input Multiple-Output (MIMO)…………………..33

Chapter 3 Field Drive Test and Performance Analysis........……………………34
3.1Test Environment…………………………………………………....34
3.2 General Test Parameters…………………………………………….37
3.3 Performance in Case of Mobile Station Speed Up to
160Km/Hr…………………………………………………………...39
3.4 Performance Analysis of the Drive Test with Speed
from 0 to 120 Km/Hr………………………………………………..41
3.4.1 When the MS is Near the Base Station (TA=1)……………….41
3.4.2 Performance Evaluation When the MS is on the
Edge of Cell (TA=5)…………………………………………..45
3.5 Parameters Analysis…………………………………..……………..47
3.6 Analysis of the Results……………………………………………....55

Chapter 4 Application of Satellite Transmission for Solving the Fast
Fading Problems………………………………………………………..57
4.1 Using Geostationary (GEO) Satellite on the Abis Interface………...57
4.2 Satellite Link Analysis and Design………………………………….59
4.2.1 The GEO Orbit………………………………………………...59
4.2.2 Calculating the Azimuth and Elevation Angle………………...60
4.2.3 Tracking Systems……………………………………….……..63
4.2.4 Antenna Pointing Loss………………………………….…......66
4.3 Radio Link Analysis…………………………………………….…. 68
4.3.1 System Parameters……………………………………….……69
4.3.2 Link Equation…………………………………………………73
4.3.3 M-ary PSK Performance in Slow Rician Fading……….….....74
4.3.4 Error Correcting Code………………………………………...76
4.4 Results of the Link Budget………………………………………….78
4.4.1 The RF Satellite Parameters…………………………………..78
4.4.2 Calculation of Eb/No for Satellite RF Link…………….……..79
4.5 Probability of Error……......………………………………………...82

Chapter 5 Conclusion……………………………………………………………...84
Bibliography………………………………………………………………………..85

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