本論文最主要的目的在於無線通信通道的研究並提出高速個人通訊服務在多重路徑環境下的位元錯誤率分析。本論文內容分為三部份。第一部份，提出一種新的室內路徑損失的預測模型。第二部份，為高速個人通訊服務在各種不同類型之多重路徑環境下的位元錯誤率分析。第三部份，為室內超寬頻通信環境之通道脈衝響應的計算。
在辦公室的環境下，對於有金屬傢俱的小房間環境提出一種新的預測模型。該模型同時考慮空間傳播損失與物體繞射損失的現象。只要根據環境的佈局方式就可以預測出接收功率的大小。該模型的優點在於使用較少的運算量就可以得到精確的結果。不像射線追蹤法那樣追蹤每一個路徑需要大的運算量。
然而，所有的無線通信系統都必需考慮在有多重電波反射、繞射與散射現象環境下的多重路徑傳播通道的影響。為了瞭解各種不同類型的無線電波傳播與通道特性的影響，例如辦公室、不同形狀的建築物以及隧道等等，本論文提出高速個人通訊服務在這些環境下的位元錯誤率分析。數值結果顯示，多重路徑效應的影響是造成環境通訊不良的主要因素。並且使用扇形天線、分集技術以及決策回授等化器等技術能夠有效地抑制室內環境的多重路徑效應，改善通訊品質以及增進位元傳輸速率。
最後，本論文提出以彈跳性射線追蹤法與反傅立葉轉換的方法來計算室內超寬頻通信環境的通道脈衝響應。通道脈衝響應的計算有考慮到物體材質在不同頻率下的影響。根據這些超寬頻通道脈衝響應的計算，可以得知在室內環境下金屬櫃對於多重路徑傳播的影響。

The main purpose of this thesis is to research on channel characteristics for wireless communications and present the bit error rate (BER) performance analysis for high-speed personal communication service in multipath environment. This thesis has three parts. The first part, a new indoor path loss prediction model is proposed. The second part, the BER performance analysis for high-speed personal communication service in different multipath environments is investigated. The third part is the impulse responses calculation for ultra-wide band (UWB) indoor communication.
In office environment, a novel prediction model for small rooms with metallic furniture is proposed. Both the propagation loss and the diffraction loss have been considered in this model. The receiver power prediction from the transmitter to the receiver antenna is predicted based on the layout of the environment. The advantages of this model are less computational load and high accuracy. It is not necessary to trace every path compared with the ray-tracing technique.
However, all wireless systems must be able to deal with the challenges of operating over a multipath propagation channel, where objects in the environment can cause multiple reflections, diffraction, and scattering to arrive at the receiver. To understand the radio propagation and channel characteristics for different multipath environments, such as office, buildings, and tunnels, the BER performance analysis for high-speed personal communication service are investigated. Numerical results have shown that the multipath effect is an important factor in an adverse communication environment and using sectored antenna, diversity techniques and decision feedback equalizer can efficiently reduce multipath effect, improve the quality of communication and increase the bit transmission rate in indoor environments.
Finally, a method for calculating the channel of UWB indoor communication systems has been presented by SBR/Image techniques and inverse Fourier transform. The frequency dependence of materials utilized in the structure on the indoor channel is accounted for in the channel simulations. By using the impulse responses of the multi-path channels, the impact of metallic cabinet to indoor multi-path is presented.

TABLE OF CONTENTS

CHINESE ABSTRACT …………………………………………………..…. I
ENGLISH ABSTRACT …………………………………………………..… II
ACKNOWLEDGMENT …………………………………………………… V
TABLE OF CONTENTS ………………...………………………………... VI
LIST OF FIGURES ………………...…………………………………….... X
LIST OF TABLES ………………...……………………………………... XIV

CHAPTER 1 INTRODUCTION ……………………………………………. 1

CHAPTER 2 FUNDAMENTS OF RADIO PROPAGATION AND           CHANNEL CHARACTERISTICS FOR WIRELESS COMMUNICATIONS …………………..…………………. 6
2.1 Introduction ……………………………………………………….... 6
2.2 Basic Concepts in Radio Wave Propagation ……………………..… 6
2.3 Propagation Power Attenuation and Coverage Prediction for indoor environments ……………………………………………………….. 9
2.4 Channel Impulse Response by SBR/Image Techniques and
Channel Parameters Calculation …………………………………... 11
2.4.1 Channel Impulse Response ………………………………………. 11
2.4.2 Channel Parameters Calculation ………………………………….. 13
2.4.2.1 Time Dispersion Parameters ………………………………. 14
2.4.2.2 Coherence Bandwidth …………………………………….. 14
2.4.2.3 Coherence time …………………………………………... 15
2.5 Mitigation of Multipath Effects …………………………………… 15
2.5.1 Equalization ……………………………………………………. 16
2.5.2 Diversity ……………………………………………………….. 17
2.5.3 Antenna Array ………………………………………………….. 18
2.6 Summary …………………………………………………………... 19

CHAPTER 3 A NOVEL PROPAGATION PREDICATION MODEL FOR SMALL ROOMS WITH METALLIC FURNITURE ……. 21
3.1 Introduction ……………………………………………………….. 21
3.2 The Novel Propagation Prediction Model ………………………… 22
3.2.1 Receiver in Line of Sight (LOS) ………………………………….. 22
3.2.2 Receiver in non-LOS ……………………………………………. 23
3.2.3 Diffraction ……………………………………………………... 23
3.3 Propagation Prediction and Measurement Results ………………... 25
3.4 Summary …………………………………………………………... 26

CHAPTER 4 SYNTHESIZING SECTORED ANTENNAS BY THE GENETIC ALGORITHM TO MITIGATE THE MULTIPATH OF INDOOR MILLIMETER WAVE CHANNEL ……….. 34
4.1 Introduction ……………………………………………………….. 34
4.2 Pattern Synthesis of Arc Array by the Genetic Algorithm ………… 35
4.3 Channel Modeling and System Description ………………………. 38
4.3.1 Calculation of the channel characteristics ………………………….. 38
4.3.2 System block diagram …………………………………………… 39
4.4 Numerical Results …………………………………………………. 41
4.5 Summary …………………………………………………………... 43

CHAPTER 5 DUAL DIVERSITY COMBINING AND DECISION FEEDBACK EQUALIZER IN INDOOR MILLIMETER–WAVE CHANNEL ……………………… 56
5.1 Introduction ……………………………………………………….. 56
5.2 Channel Impulse Response by SBR/Image Techniques and
Channel Parameters Calculation …………………………………... 57
5.2.1 Calculation of the channel characteristics ………………………….. 57
5.2.2 System block diagram …………………………………………… 58
5.2.3 Space Diversity techniques ………………………………………. 61
5.3 Numerical Results …………………………………………………. 62
5.4 Summary …………………………………………………………... 64

CHAPTER 6 BER PERFORMANCE OF WIRELESS BPSK COMMUNICATION SYSTEM IN TUNNELS WITH AND WITHOUT TRAFFIC ……………………………………. 76
6.1 Introduction ……………………………………………………….. 76
6.2 Channel Modeling and System Description ………………………. 77
6.2.1 Calculation of the channel characteristics ………………………….. 77
6.2.2 System block diagram …………………………………………… 78
6.3 Numerical Results …………………………………………………. 80
6.4 Summary …………………………………………………………... 83

CHAPTER 7 ULTRA-WIDE BAND CHANNEL CALCULATION BY SBR/IMAGE TECHNIQUES FOR INDOOR COMMUNICATION ……………………………………... 98
7.1 Introduction ……………………………………………………….. 98
7.2 UWB Channel Calculation ………………………………………... 99
7.2.1 Frequency responses for sinusoid waves by SBR/Image techniques …. 100
7.2.2 Inverse Fast Fourier Transform (IFFT) and Hermitian Processing …... 101
7.3 Numerical Results ………………………………………………... 101
7.4 Summary …………………………………………………………. 102

CHAPTER 8 CONCLUSIONS …………………………………………... 112

REFERENCE …………………………………………………………..… 114








LIST OF FIGURES

Figure 3.1 The chart of the path loss, the receivers are in direct line of sight and non-line of sight. ………………………………………..…. 27
Figure 3.2 Knife-edge diffraction geometry. An knife-edge obstruction blocking the line of sight path. ………………………………… 28
Figure 3.3(a) Top view of Microwave Laboratory with two different access points (AP1 and AP2). ……………..…………………….…. 29
Figure 3.3(b) Comparison between measurements and simulations of access point 1 (AP1). ………………………...…………………….. 30
Figure 3.3(c) Comparison between measurements and simulations of access point 2 (AP2). ………………………………………………. 31
Figure 3.4(a) Top view of programmable logic control laboratory. ……….. 32
Figure 3.4(b) Comparison between measurements and simulations. ……… 33
Figure 4.1 Geometry of circular arc array shaded circles indicate “on” elements. ……………………………………………………... 45
Figure 4.2 The flow chart for genetic algorithms. …………………………. 46
Figure 4.3 Model of a typical room with four metal bookcases. The dark rectangles represent metal bookcases. …………………………. 47
Figure 4.4 Block diagram of equivalent baseband communication system. . 48
Figure 4.5 Radiation pattern of circular arc array synthesized by the genetic algorithm. ………………………………………………………... 49
Figure 4.6(a) Impulse response for line of sight case with and without sector antenna for receiver at Rx (0.75m, 6.25m, 1.5m) without sector antenna. …………………………………………………….. 50
Figure 4.6(b) Impulse response for line of sight case with and without sector antenna for receiver at Rx (0.75m, 6.25m, 1.5m) with sector antenna. …………………………………………………….. 51
Figure 4.7(a) Impulse response for non line of sight case with and without sector antenna for receiver at Rx (0.75m, 10m, 1.5m) without sector antenna. ……………………………………………… 52
Figure 4.8 Cumulative distribution of rms delay spreads. ………………… 53
Figure 4.9 Outage probabilities versus transmission rate for three different receiver structures. ……………………………………………... 54
Figure 5.1(a) An arched building modeled by triangular facets. …………... 65
Figure 5.1(b) A rectangular building modeled by triangular facets. ……….. 66
Figure 5.2(a) Block diagrams of equivalent baseband communication system without diversity system. …………………………………… 67
Figure 5.2(b) Block diagrams of equivalent baseband communication system with dual space antenna diversity system. …………………. 68
Figure 5.3 The structure of a decision feedback equalizer. ………………... 69
Figure 5.4(a) Impulse responses of arched buildings for the receiver at Rx( 5m, 2.5m, 1.5m ). …………………………………….... 70
Figure 5.4(b) Impulse responses of rectangular buildings for the receiver at Rx( 5m, 2.5m, 1.5m ). ……………………………………… 71
Figure 5.5 Cumulative distributions of rms delay spreads for the arched and rectangular buildings. ………………………………………….. 72
Figure 5.6(a) Outage probabilities versus transmission rate for the arched buildings and three different receiver structures. …………... 73
Figure 5.6(b) Outage probabilities versus transmission rate for the rectangular buildings and three different receiver structures. …………... 74
Figure 6.1(a) A tunnel structure modeled by triangular facets. …….……… 85
Figure 6.1(b) Top view of the tunnel structure. ……………………………. 86
Figure 6.1(c) The cross section of the tunnel. ……………………………... 87
Figure 6.2(a) Block diagrams of equivalent baseband communication system without diversity system. …………………………………… 88
Figure 6.2(b) Block diagrams of equivalent baseband communication system with dual space antenna diversity system. …………………. 89
Figure 6.3(a) Impulse response for receiver at Rx1(59m, 108m, 1.5m) of the empty tunnel. ………………………………………………. 90
Figure 6.3(b) Impulse response for receiver at Rx2(107m, 50m, 1.5m) of the empty tunnel. ……………………………………………….. 91
Figure 6.4(a) Impulse responses for receiver at Rx1(59m, 108m, 1.5m) of the tunnel with traffic. ………………………………………….. 92
Figure 6.4(b) Impulse responses for receiver at Rx2(107m, 50m, 1.5m) of the tunnel with traffic. ………………………………………….. 93
Figure 6.5 Cumulative distributions of rms delay spreads for tunnels withand without traffic. …………………………………………………. 94
Figure 6.6(a) Outage probabilities versus transmission rate for the empty tunnel with three different receiver structures. ……………... 95
Figure 6.6(b) Outage probabilities versus transmission rate for the trafficked tunnel with three different receiver structures. …………….. 96
Figure 7.1 Top view of the Microwave Laboratory. Tx denotes the transmitter and Rx denotes the Receiver. The transmitter is located at Tx(560cm, 250cm, 120cm). ……………………………….......104
Figure 7.2(a) UWB impulse responses of the Microwave Laboratory at Rx1(520cm, 720cm, 85cm) with L shape metal cabinet. …. 105
Figure 7.2(b) UWB impulse responses of the Microwave Laboratory at Rx1(520cm, 720cm, 85cm) without L shape metal cabinet. ……………………………………………………. 106
Figure 7.3(a) UWB impulse responses of the Microwave Laboratory at Rx2(490cm, 320cm, 85cm) with L shape metal cabinet. …. 107
Figure 7.3(b) UWB impulse responses of the Microwave Laboratory at Rx2(490cm, 320cm, 85cm) without L shape metal cabinet. ……………………………………………………. 108
Figure 7.4(a) UWB impulse responses of the Microwave Laboratory at Rx3(800cm, 280cm, 85cm) with L shape metal cabinet. …. 109
Figure 7.4(b) UWB impulse responses of the Microwave Laboratory at Rx3(800cm, 280cm, 85cm) without L shape metal cabinet. …………………………………………………….. 110





LIST OF TABLES

Table 5.1 Mean and standard deviation of the rms delay spreads for the arched and rectangular buildings. ……………………………………….. 75
Table 6.1 Mean and standard deviation of the rms delay spreads for tunnels with and without traffic. …………………………………………. 97
Table 7.1 The dielectric constant and loss tangent of concrete walls for different frequency. …………………………………………….. 111

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