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    Within the United States, satellites are not used for telephone (voice) links. The de-velopment of terrestrial optical fiber links has made satellite transmission of telephonetraffic uneconomic, and the delay associated with GEO satellite link is a nuisance.Domestic satellites serving the United States now carry video signals for distribution tocable TV companies or direct to homes and serve networks of VSAT stations linked tocentral hubs in major cities. The development of direct'to home satellite broadcast tele-vision (DBS-TV) has had a major impact on the marketplace. In rhe United States, digi-tal DBS-TV transmissions are nw received in 15 million homes (2001 figure), and inEurope a similar number of homes receive satellite television programming. Video distri-bution, to cable companies and direct to home, accounts for more than half of all theworldwide earnings from satellite communication systems.

    The authors would like to thank heir colieagues and students who, over the years,have made many valuable suggestions to improve this text. Their advice has been heeded,and the second edition of Satellite Communication is the better for it. Many more workedexamples have been added to the second edition to illustrate how calculations are carriedout for each topic.


    Preface ix

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    Preface ix

    1- Introduction I1.1 Background 11.2 A Brief History of Satellite Communications 31.3 Satellite Communications in 2000 6I 4. Overview of Satellite Communications 151-5 Summary l6Refercnces l6

    2. Ortlital Mechanics and Launchers 17Orbital Mechanics 11Developing the Equations of the Orbit l1Kepler's Three Laws of Planetary Motion 22Describing the Orbit of a Satellite 23Locating the Sateilite in the Orbit 25Locating the Satellite with Respect to the Earth 21Orbital Elements 29Exampie 2.1.1 Geostationary Satellite Orbit Radius 29Example 2.l.2Low Earth Orbit 29Example 2.1.3 ElliPtical Orbit 30Look Angle Determination 30The Subsatellite Point 31Elevation Angle Calculation 32Azimuth Angle Calculation 34Specialization to Geostationary Satellites 35Visibil Test 36Example 2.2.1 Geostationary Satellite Look Angles 36OrbitalPerturbations 38Longitudinal Changes: Effects of the Earth's Oblateness 39Inclination Changes: Effects of the Sun and the Moon 40Example 2.3.1 Drift with a Geosttionary Satellite 42

    2.4 Orbit Determination 422.5 Launches and Launch Vehicles 43

    Expendable Launch Vehicles (ELVs) 44Placing Satellites into Geostationary Orbit 48

    2.6 Orbital Effects in Communications Systems Performance 49Doppler Shift 49Example 2.6.1 Doppler Shift for a LEO Satellite 50R.ange Variations 51Solar EcliPse 51Sun Transit Outage 53







    2;7 Summary 54References 54Problems 55

    3. Satellites 573.1 Satellite Subsystems 51

    Attitude and Orbit Control Systern (AOCS) 57Telemetry, Tracking, Command and Monitoring (TTC&M)Power System 59Communications Subsysterns 59Satellite Antennas 59

    3.2 Attitude and Orbit Control System (AOCS) 60Attitude Control System 60Orbit Control System 66

    3.3 Telemetry, Tracking, Command, and Monitoring 68Telemetry and Monitoring System 68Tracking 68Command 10

    3.4 Power Systems 713.5 Communications Subsysterns 12

    Description of the Communications Systeur 12Transponders 75

    3.6 Satellite Antennas 80Basic Antenna Types and Relationships 80Example 3.6.1 Global Beam Antenna 82Example 3.6.2 Regional Coverage Antenna 83Satellite Antennas in Practice 83

    3.7 Equipment Reliability and Space Qualification 87Space Qualification 87Reliability 88Redundancy 90

    3.8 Summary 92References 93Problems 93

    4. Satellite Link Design 964.1 Introduction 964.2 Basic Transmission Theory 100

    Example 4.2.1 lO4Exanryle 4.2.2 104

    4.3 System Noise Temperature and G/T RatioNoise Temperature 105Calculation of System Noise TemperatureExample 4.3.1 110Example 4.3.2 110Noise Figure and Noise Temperature 111Example 4.3.3 112GIT Ratio for Earth Stations 112Example 4.3.4 ll2


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    Design of Downlinks ll2Link Budgets I 13Link Budget Example: C-Band Downlink for Earth Coverage Beam 115Satellite Systems Using Small Earth Stations 117Direct Broadcast TV 118Example 4.5.1 123Uplink Design 124Exampie 4.6.1 121Design for Specified C/N: Combining C/N and C/I Values in Satellite Links 121Example 4.7.1 129Overall (C/N)o with Uplink and Downlink Attenuation 129Uplink and Downlink Attenuation in Rain 130Uplink Attenurtion and (C/N),, 130Downlink Attenuation and (C/N)u" 131Systern Design tbr Specihc Performance 131Satellite Communication Link Design Procedure 131System Design Examples 132System Design Example 4.8.1 133Ku Band Uplink Design 133Ku Band Downlink Design 134Rain Effects at Ku Band 135Summary of Ku Band Link Performance 131System Design Example 4.8.2 Personal Communication System Using

    Low Earth Orbit Sateilites 131Inbound Link: Mobile Terminal to Gateway Station l4IMobile Terminal ro Satellite Link 142Satellite to Gateway Station Link 143Outbound Link 144Downlik C/N Budget 145Optimizing System Performance L46Link Margins with FEC 147Rain Attenuation at Ku Band 147Path Blockage at L-Band 149Summary of L-band Mobile PCS System Performance 149




    4.9 Summary 150References 150Problems 151

    5. Modulation and Multiplexing Techniques for Satellite Links 156Frequency Modulation l5lWaveform Equation for FM 158Bandwidth of FM Signals: Carson's Rule 159Baseband S/N Ratio for FM Signals 159Pre-emphasis and de-emphasis 16lPre-emphasis 162Analog FM Transmission by Satellitc l&l*l*ision Siguals io5S/N R.atios for FM Video Transmissior i6iExample 5.2.1 168





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    FM Threshold 168SCPC FM Links 169Example 5.2.2 L70Data Transmission Using Analog FM Channels 170Example 5.2.3 171Digital Transmission 112Baseband Digital Signals 172Ba-ehand Transrnission of Digital Data 112Band-pass Transmission of Digital Data 119Example 5.3.1 181Exarnple 5.3.2 18lTransmission of QPSK Signals through a Bandlimited ChannelExarnpie 5.3.3 185Example 5.3.3 185Digitai Modulation and Demodulation 187Terminology 187Modulation and Coding 187Bit and Symbol Error Rates 188Binary Phase Shift Keying (BPSK) 189Probability of a Symbol Error 191BPSK Bit Error Rate 194QPSK Bit Error Rate 194Example 5.4.1 195Exarnpie 5.4.2 191Generation of Quadrature Phase Shift Ke-ving (QPSK) SignalsQPSK Variants 199

    5.5 Digital Transmission of Analog Signals 201Sampling and Quantizing 2AlNonuniform Quantization: Compression and Expansion 204Signal-to-Noise Ratio in Digital Voice Systems 206Digital Television 208

    5.6 Time Division MulPlexing 209TDM Terminology: The U-S. T1 24-Channel System 29other TDM Systems zllChannel Synchronization in TDM 212

    5.7 Summary 212References 213Problems 2146. Multiple Access 2216.1 Introduction 22I6.2 Frequency Division Multiple Access (FDMA) 223

    Intermodulation 226Intermodulation ExamPle 228Calculation of C/N with Intermodulation Z3OExample 6.2.1 Power Sharing in FDMA 231Example 6.2.2 Channel Capacity with Demand Access FDMA 232Tirne Division Multiple,{"ccess (TDMA) 233Bits, Symbois, and Cbarels 234TDMA Frame Structure 235


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    Example 6.3.1 TDMA in a Fixed Station Network 231Reference Burst and Preamble 238Unique Word 239Guard Times 241Synchronization in TDMA Networks 242Transmitter Power in TDMA Networks 243Example 6.3.2 TDMA in a VSAI Network 244Example 6.3.2 TDMA in a Fixed Earth Station Network 244Satellite Switched TDMA 246Onboard Processing 246Baseband Processing Transponders 241Satellite Switphed TDMA with Onboard Processing 248Demand Access Multiple Access (DAMA) 249Example 6.5.1 FDMA-SCPC-DA 252Random Access 254Packet Radio Systems and Protocols 254Code Division Multiple Access (CDMA) 251Spread Spectrum Transmission and Reception 258DS-SS CDMA CaPacitY 262Example 6.8.1 CDMA in a Fixed Earth Station Network 263Example 6.8.2 CDMA in an LEO Sateilite Netu'ork 263Example 6.8.3 GPS 264

    6.9 Summary 266References 261Problems 2617. Error Control for Digital Satellite Links 2737.1 Error Detection and Correction 2137.2 Channel CapacitY 2757 -3 Error Control Coding 271

    Example 7.3.1 278, Linear and CYclic Block Codes 279

    Golay Codes 2807 -4 Performance of Block Error Correction Codes 2817.5 Convolutional Codes 2827.6 Implementation of Error Detection on Satellite Links 284

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