SATELLITE COMMUNICATIONSSYSTEMSFifth EditionSATELLITE COMMUNICATIONSSYSTEMSSystems, Techniques and TechnologyFifth EditionGerard MaralEcole Nationale Superieure des Telecommunications,Site de Toulouse, FranceMichel BousquetEcole Nationale Superieure de lAeronautique et de lEspace (SUPAERO),Toulouse, FranceRevisions to fth edition by Zhili SunUniversity of Surrey, UKwith contributions from Isabelle Buret,Thales Alenia SpaceCopyright 1986, 1993, 1998, 2002This edition rst published 2009 2009 John Wiley & Sons Ltd.Registered ofceJohn Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United KingdomFor details of our global editorial ofces, for customer services and for information about how to apply forpermission to reuse the copyright material in this book please see our website at www.wiley.com.The right of the author to be identied as the author of this work has been asserted in accordance with theCopyright, Designs and Patents Act 1988.All rights reserved. No part of this publicationmay be reproduced, storedin a retrieval system, or transmitted,in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except aspermitted by the UKCopyright, Designs and Patents Act 1988, without the prior permission of the publisher.Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not beavailable in electronic books.Designations used by companies to distinguish their products are often claimed as trademarks. All brandnames and product names used in this book are trade names, service marks, trademarks or registeredtrademarks of their respective owners. The publisher is not associated with any product or vendor mentionedin this book. This publication is designed to provide accurate and authoritative information in regard to thesubject matter covered. It is sold on the understanding that the publisher is not engaged in renderingprofessional services. If professional advice or other expert assistance is required, the services of a competentprofessional should be sought.Library of Congress Cataloging-in-Publication DataMaral, Gerard.[Systemes de telecommunications par satellites. English]Satellite communications systems / Gerard Maral, Michel Bousquet. 5th ed.p. cm.Includes bibliographical references and index.ISBN 978-0-470-71458-4 (cloth)1. Articial satellites in telecommunication. I. Bousquet, Michel. II. Title.TK5104.M3513 2009621.3825dc22 2009023579A catalogue record for this book is available from the British Library.ISBN 978-0-470-71458-4 (H/B)Typeset in 9/11 pt Palatino by Thomson Digital, Noida, India.Printed in Singapore by Markono Print Media Pte Ltd.This book is printed on acid-free paper responsibly manufactured from sustainable forestry,in which at least two trees are planted for each one used for paper production.Original translation into English by J.C.C. Nelson.CONTENTSACKNOWLEDGEMENT xvACRONYMS xviiNOTATION xxv1 INTRODUCTION 11.1 Birth of satellite communications 11.2 Development of satellite communications 11.3 Conguration of a satellite communications system 31.3.1 Communications links 41.3.2 The space segment 51.3.3 The ground segment 81.4 Types of orbit 91.5 Radio regulations 121.5.1 The ITU organisation 121.5.2 Space radiocommunications services 131.5.3 Frequency allocation 131.6 Technology trends 141.7 Services 151.8 The way forward 17References 182 ORBITS AND RELATED ISSUES 192.1 Keplerian orbits 192.1.1 Keplers laws 192.1.2 Newtons law 192.1.3 Relative movement of two point bodies 202.1.4 Orbital parameters 232.1.5 The earths orbit 282.1.6 Earthsatellite geometry 352.1.7 Eclipses of the sun 412.1.8 Sunsatellite conjunction 422.2 Useful orbits for satellite communication 432.2.1 Elliptical orbits with non-zero inclination 432.2.2 Geosynchronous elliptic orbits with zero inclination 542.2.3 Geosynchronous circular orbits with non-zero inclination 562.2.4 Sub-synchronous circular orbits with zero inclination 592.2.5 Geostationary satellite orbits 592.3 Perturbations of orbits 682.3.1 The nature of the perturbations 692.3.2 The effect of perturbations; orbit perturbation 712.3.3 Perturbations of the orbit of geostationary satellites 732.3.4 Orbit corrections: station keeping of geostationary satellites 812.4 Conclusion 97References 973 BASEBAND SIGNALS AND QUALITY OF SERVICE 993.1 Baseband signals 993.1.1 Digital telephone signal 1003.1.2 Sound signals 1033.1.3 Television signals 1043.1.4 Data and multimedia signals 1073.2 Performance objectives 1083.2.1 Telephone 1083.2.2 Sound 1083.2.3 Television 1083.2.4 Data 1083.3 Availability objectives 1093.4 Delay 1113.4.1 Delay in terrestrial network 1113.4.2 Propagation delay over satellite links 1113.4.3 Baseband-signal processing time 1123.4.4 Protocol-induced delay 1123.5 Conclusion 112References 1134 DIGITAL COMMUNICATIONS TECHNIQUES 1154.1 Baseband formatting 1154.1.1 Encryption 1154.1.2 Scrambling 1174.2 Digital modulation 1184.2.1 Two-state modulationBPSK and DE-BPSK 1194.2.2 Four-state modulationQPSK 1204.2.3 Variants of QPSK 1214.2.4 Higher-order PSK and APSK 1244.2.5 Spectrum of unltered modulated carriers 1254.2.6 Demodulation 1254.2.7 Modulation spectral efciency 1304.3 Channel coding 1314.3.1 Block encoding and convolutional encoding 1324.3.2 Channel decoding 1324.3.3 Concatenated encoding 1334.3.4 Interleaving 1344.4 Channel coding and the powerbandwidth trade-off 1354.4.1 Coding with variable bandwidth 1354.4.2 Coding with constant bandwidth 1374.4.3 Example: Downlink coding with on-board regeneration 1394.4.4 Conclusion 139vi Contents4.5 Coded modulation 1404.5.1 Trellis coded modulation 1414.5.2 Block coded modulation 1444.5.3 Decoding coded modulation 1454.5.4 Multilevel trellis coded modulation 1454.5.5 TCM using a multidimensional signal set 1464.5.6 Performance of coded modulations 1464.6 End-to-end error control 1464.7 Digital video broadcasting via satellite (DVB-S) 1484.7.1 Transmission system 1484.7.2 Error performance requirements 1524.8 Second generation DVB-S 1524.8.1 New technology in DVB-S2 1534.8.2 Transmission system architecture 1544.8.3 Error performance 1564.9 Conclusion 1574.9.1 Digital transmission of telephony 1574.9.2 Digital broadcasting of television 159References 1605 UPLINK, DOWNLINK AND OVERALL LINK PERFORMANCE;INTERSATELLITE LINKS 1635.1 Conguration of a link 1635.2 Antenna parameters 1645.2.1 Gain 1645.2.2 Radiation pattern and angular beamwidth 1655.2.3 Polarisation 1685.3 Radiated power 1705.3.1 Effective isotropic radiated power (EIRP) 1705.3.2 Power ux density 1705.4 Received signal power 1715.4.1 Power captured by the receiving antenna and free space loss 1715.4.2 Example 1: Uplink received power 1725.4.3 Example 2: Downlink received power 1735.4.4 Additional losses 1745.4.5 Conclusion 1765.5 Noise power spectral density at the receiver input 1765.5.1 The origins of noise 1765.5.2 Noise characterisation 1775.5.3 Noise temperature of an antenna 1805.5.4 System noise temperature 1855.5.5 System noise temperature: Example 1865.5.6 Conclusion 1865.6 Individual link performance 1865.6.1 Carrier power to noise power spectral density ratio at receiver input 1875.6.2 Clear sky uplink performance 1875.6.3 Clear sky downlink performance 1895.7 Inuence of the atmosphere 1935.7.1 Impairments caused by rain 1935.7.2 Other impairments 2075.7.3 Link impairmentsrelative importance 209Contents vii5.7.4 Link performance under rain conditions 2095.7.5 Conclusion 2105.8 Mitigation of atmospheric impairments 2105.8.1 Depolarisation mitigation 2105.8.2 Attenuation mitigation 2115.8.3 Site diversity 2115.8.4 Adaptivity 2125.8.5 Cost-availability trade-off 2125.9 Overall link performance with transparent satellite 2135.9.1 Characteristics of the satellite channel 2145.9.2 Expression for (C/N0)T 2185.9.3 Overall link performance for a transparent satellite without interferenceor intermodulation 2215.10 Overall link performance with regenerative satellite 2255.10.1 Linear satellite channel without interference 2265.10.2 Non-linear satellite channel without interference 2275.10.3 Non-linear satellite channel with interference 2285.11 Link performance with multibeam antenna coverage vs monobeamcoverage 2305.11.1 Advantages of multibeam coverage 2315.11.2 Disadvantages of multibeam coverage 2345.11.3 Conclusion 2375.12 Intersatellite link performance 2375.12.1 Frequency bands 2385.12.2 Radio-frequency links 2385.12.3 Optical links 2395.12.4 Conclusion 245References 2466 MULTIPLE ACCESS 2476.1 Layered data transmission 2476.2 Trafc parameters 2486.2.1 Trafc intensity 2486.2.2 Call blocking probability 2486.2.3 Burstiness 2486.3 Trafc routing 2496.3.1 One carrier per station-to-station link 2506.3.2 One carrier per transmitting station 2516.3.3 Comparison 2516.4 Access techniques 2516.4.1 Access to a particular satellite channel (or transponder) 2516.4.2 Multiple access to the satellite channel 2526.4.3 Performance evaluationefciency 2536.5 Frequency division multiple access (FDMA) 2536.5.1 TDM/PSK/FDMA 2546.5.2 SCPC/FDMA 2546.5.3 Adjacent channel interference 2546.5.4 Intermodulation 2546.5.5 FDMA efciency 2586.5.6 Conclusion 260viii Contents6.6 Time division multiple access (TDMA) 2606.6.1 Burst generation 2606.6.2 Frame structure 2626.6.3 Burst reception 2646.6.4 Synchronisation 2656.6.5 TDMA efciency 2706.6.6 Conclusion 2716.7 Code division multiple access (CDMA) 2726.7.1 Direct sequence (DS-CDMA) 2736.7.2 Frequency hopping CDMA (FH-CDMA) 2766.7.3 Code generation 2776.7.4 Synchronisation 2786.7.5 CDMA efciency 2806.7.6 Conclusion 2816.8 Fixed and on-demand assignment 2836.8.1 The principle 2836.8.2 Comparison between xed and on-demand assignment 2836.8.3 Centralised or distributed management of on-demand assignment 2846.8.4 Conclusion 2846.9 Random access 2856.9.1 Asynchronous protocols 2866.9.2 Protocols with synchronisation 2896.9.3 Protocols with assignment on demand 2906.10 Conclusion 290References 2917 SATELLITE NETWORKS 2937.1 Network reference models and protocols 2937.1.1 Layering principle 2937.1.2 Open Systems Interconnection (OSI) reference model 2947.1.3 IP reference model 2957.2 Reference architecture for satellite networks 2967.3 Basic characteristics of satellite networks 2987.3.1 Satellite network topology 2987.3.2 Types of link 3007.3.3 Connectivity 3007.4 Satellite on-board connectivity 3027.4.1 On-board connectivity with transponder hopping 3027.4.2 On-board connectivity with transparent processing 3037.4.3 On-board connectivity with regenerative processing 3087.4.4 On-board connectivity with beam scanning 3137.5 Connectivity through intersatellite links (ISL) 3147.5.1 Links between geostationary and low earth orbit satellites (GEOLEO) 3147.5.2 Links between geostationary satellites (GEOGEO) 3147.5.3 Links between low earth orbit satellites (LEOLEO) 3187.5.4 Conclusion 3197.6 Satellite broadcast networks 3197.6.1 Single uplink (one programme) per satellite channel 3207.6.2 Several programmes per satellite channel 3217.6.3 Single uplink with time division multiplex (TDM) of programmes 3217.6.4 Multiple uplinks with time division multiplex (TDM) of programmes on downlink 322Contents ix7.7 Broadband satellite networks 3227.7.1 Overview of DVB-RCS and DVB-S/S2 network 3247.7.2 Protocol stack architecture for broadband satellite networks 3257.7.3 Physical layer 3267.7.4 Satellite MAC layer 3337.7.5 Satellite link control layer 3387.7.6 Quality of service 3407.7.7 Network layer 3437.7.8 Regenerative satellite mesh network architecture 3467.8 Transmission control protocol 3517.8.1 TCP segment header format 3517.8.2 Connection set up and data transmission 3527.8.3 Congestion control and ow control 3537.8.4 Impact of satellite channel characteristics on TCP 3547.8.5 TCP performance enhancement 3557.9 IPv6 over satellite networks 3567.9.1 IPv6 basics 3577.9.2 IPv6 transitions 3587.9.3 IPv6 tunnelling through satellite networks 3587.9.4 6to4 translation via satellite networks 3597.10 Conclusion 359References 3608 EARTH STATIONS 3638.1 Station organisation 3638.2 Radio-frequency characteristics 3648.2.1 Effective isotropic radiated power (EIRP) 3648.2.2 Figure of merit of the station 3668.2.3 Standards dened by international organisations and satellite operators 3668.3 The antenna subsystem 3768.3.1 Radiation characteristics (main lobe) 3798.3.2 Side-lobe radiation 3798.3.3 Antenna noise temperature 3808.3.4 Types of antenna 3858.3.5 Pointing angles of an earth station antenna 3908.3.6 Mountings to permit antenna pointing 3938.3.7 Tracking 3998.4 The radio-frequency subsystem 4088.4.1 Receiving equipment 4088.4.2 Transmission equipment 4118.4.3 Redundancy 4178.5 Communication subsystems 4178.5.1 Frequency translation 4188.5.2 Amplication, ltering and equalisation 4208.5.3 Modems 4218.6 The network interface subsystem 4258.6.1 Multiplexing and demultiplexing 4258.6.2 Digital speech interpolation (DSI) 4268.6.3 Digital circuit multiplication equipment (DCME) 4278.6.4 Echo suppression and cancellation 4308.6.5 Equipment specic to SCPC transmission 432x Contents8.7 Monitoring and control; auxiliary equipment 4328.7.1 Monitoring, alarms and control (MAC) equipment 4328.7.2 Electrical power 4328.8 Conclusion 433References 4349 THE COMMUNICATION PAYLOAD 4359.1 Mission and characteristics of the payload 4359.1.1 Functions of the payload 4359.1.2 Characterisation of the payload 4369.1.3 The relationship between the radio-frequency characteristics 4379.2 Transparent repeater 4379.2.1 Characterisation of non-linearities 4389.2.2 Repeater organisation 4479.2.3 Equipment characteristics 4539.3 Regenerative repeater 4659.3.1 Coherent demodulation 4659.3.2 Differential demodulation 4669.3.3 Multicarrier demodulation 4669.4 Multibeam antenna payload 4679.4.1 Fixed interconnection 4679.4.2 Recongurable (semi-xed) interconnection 4689.4.3 Transparent on-board time domain switching 4689.4.4 On-board frequency domain transparent switching 4719.4.5 Baseband regenerative switching 4729.4.6 Optical switching 4759.5 Introduction to exible payloads 4759.6 Solid state equipment technology 4779.6.1 The environment 4779.6.2 Analogue microwave component technology 4779.6.3 Digital component technology 4789.7 Antenna coverage 4799.7.1 Service zone contour 4799.7.2 Geometrical contour 4829.7.3 Global coverage 4829.7.4 Reduced or spot coverage 4849.7.5 Evaluation of antenna pointing error 4869.7.6 Conclusion 4989.8 Antenna characteristics 4989.8.1 Antenna functions 4989.8.2 The radio-frequency coverage 5009.8.3 Circular beams 5019.8.4 Elliptical beams 5049.8.5 The inuence of depointing 5059.8.6 Shaped beams 5079.8.7 Multiple beams 5109.8.8 Types of antenna 5119.8.9 Antenna technologies 5159.9 Conclusion 524References 524Contents xi10 THE PLATFORM 52710.1 Subsystems 52810.2 Attitude control 52910.2.1 Attitude control functions 53010.2.2 Attitude sensors 53110.2.3 Attitude determination 53210.2.4 Actuators 53410.2.5 The principle of gyroscopic stabilisation 53610.2.6 Spin stabilisation 54010.2.7 Three-axis stabilisation 54110.3 The propulsion subsystem 54710.3.1 Characteristics of thrusters 54710.3.2 Chemical propulsion 54910.3.3 Electric propulsion 55310.3.4 Organisation of the propulsion subsystem 55810.3.5 Electric propulsion for station keeping and orbit transfer 56110.4 The electric power supply 56210.4.1 Primary energy sources 56210.4.2 Secondary energy sources 56710.4.3 Conditioning and protection circuits 57410.4.4 Example calculations 57810.5 Telemetry, tracking and command (TTC) and on-board data handling (OBDH) 58010.5.1 Frequencies used 58110.5.2 The telecommand links 58110.5.3 Telemetry links 58210.5.4 Telecommand (TC) and telemetry (TM) message format standards 58310.5.5 On-board data handling (OBDH) 58810.5.6 Tracking 59310.6 Thermal control and structure 59610.6.1 Thermal control specications 59710.6.2 Passive control 59810.6.3 Active control 60110.6.4 Structure 60110.6.5 Conclusion 60310.7 Developments and trends 604References 60611 SATELLITE INSTALLATION AND LAUNCH VEHICLES 60711.1 Installation in orbit 60711.1.1 Basic principles 60711.1.2 Calculation of the required velocity increments 60911.1.3 Inclination correction and circularisation 61011.1.4 The apogee (or perigee) motor 61711.1.5 Injection into orbit with a conventional launcher 62211.1.6 Injection into orbit from a quasi-circular low altitude orbit 62611.1.7 Operations during installation (station acquisition) 62711.1.8 Injection into orbits other than geostationary 63011.1.9 The launch window 63111.2 Launch vehicles 63111.2.1 Brazil 63211.2.2 China 635xii Contents11.2.3 Commonwealth of Independent States (CIS) 63611.2.4 Europe 64111.2.5 India 64811.2.6 Israel 64811.2.7 Japan 64911.2.8 South Korea 65211.2.9 United States of America 65211.2.10 Reusable launch vehicles 66011.2.11 Cost of installation in orbit 661References 66112 THE SPACE ENVIRONMENT 66312.1 Vacuum 66312.1.1 Characterisation 66312.1.2 Effects 66312.2 The mechanical environment 66412.2.1 The gravitational eld 66412.2.2 The earths magnetic eld 66512.2.3 Solar radiation pressure 66612.2.4 Meteorites and material particles 66712.2.5 Torques of internal origin 66712.2.6 The effect of communication transmissions 66812.2.7 Conclusions 66812.3 Radiation 66812.3.1 Solar radiation 66912.3.2 Earth radiation 67112.3.3 Thermal effects 67112.3.4 Effects on materials 67212.4 Flux of high energy particles 67212.4.1 Cosmic particles 67212.4.2 Effects on materials 67412.5 The environment during installation 67512.5.1 The environment during launching 67612.5.2 Environment in the transfer orbit 677References 67713 RELIABILITY OF SATELLITE COMMUNICATIONS SYSTEMS 67913.1 Introduction of reliability 67913.1.1 Failure rate 67913.1.2 The probability of survival or reliability 68013.1.3 Failure probability or unreliability 68013.1.4 Mean time to failure (MTTF) 68213.1.5 Mean satellite lifetime 68213.1.6 Reliability during the wear-out period 68213.2 Satellite system availability 68313.2.1 No back-up satellite in orbit 68313.2.2 Back-up satellite in orbit 68413.2.3 Conclusion 68413.3 Subsystem reliability 68513.3.1 Elements in series 685Contents xiii13.3.2 Elements in parallel (static redundancy) 68513.3.3 Dynamic redundancy (with switching) 68713.3.4 Equipment having several failure modes 69013.4 Component reliability 69113.4.1 Component reliability 69113.4.2 Component selection 69213.4.3 Manufacture 69313.4.4 Quality assurance 693INDEX 697xiv ContentsACKNOWLEDGEMENTReproduction of gures extracted from the 1990 Edition of CCIR Volumes (XVIIthPlenary Assembly, D usseldorf, 1990), the Handbook on Satellite Communications (ITUGeneva, 1988) and the ITU-R Recommendations is made with the authorisation of theInternational Telecommunication Union (ITU) as copyright holder.The choice of the excerpts reproduced remains the sole responsibility of the authorsand does not involve in any way the ITU.The complete ITU documentation can be obtained from:International Telecommunication UnionGeneral Secretariat, Sales SectionPlace des Nations, 1211 GENEVA 20, SwitzerlandTel: +41 22 730 51 11 Tg: Burinterna GenevaTelefax: + 41 22 730 51 94 Tlx: 421 000 uit chACRONYMSAAL ATM Adaptation LayerA/D Analog-to-Digital conversionABCS Advanced Business Communicationsvia SatelliteABM Apogee Boost MotorACD Average Call DistanceACI Adjacent Channel InterferenceACK ACKnowledgementACTS Advanced CommunicationsTechnology SatelliteADC Analog to Digital ConverterADM Adaptive Delta ModulationADPCM Adaptive Pulse Code ModulationADSL Asymmetric Digital Subscriber LineAES Audio Engineering SocietyAGCH Access Granted CHannelAKM Apogee Kick MotorALC Automatic Level ControlALG Application Level GatewayAM Amplitude ModulationAMAP Adaptive Mobile Access ProtocolAMP AMPlierAMPS Advanced Mobile Phone ServiceAMSC American Mobile Satellite Corp.AMSS Aeronautical Mobile Satellite ServiceANSI American National StandardsInstituteAOCS Attitude and Orbit Control SystemAOM Administration, Operation andMaintenanceAOR Atlantic Ocean RegionAPC Adaptive Predictive CodingAPD Avalanche PhotodetectorAPI Application ProgrammingInterfaceAR Axial RatioARQ Automatic Repeat RequestARQ-GB(N) Automatic repeat ReQuest-GoBackNARQ-SR Automatic repeat ReQuest-SelectiveRepeatARCS Astra Return Channel SystemARQ-SW Automatic repeat ReQuest-Stop andWaitARTES Advanced Research inTElecommunications Systems(ESA programme)ASCII American Standard Code forInformation InterchangeASIC Application Specic IntegratedCircuitASN Acknowledgement SequenceNumberASN Abstract Syntax NotationASTE Advanced Systems andTelecommunications Equipment(ESA programme)ASTP Advanced Systems and TechnologyProgramme (ESA programme)ASYNC ASYNChronous data transferATA Auto-Tracking AntennaATC Adaptive Transform CodingATM Asynchronous Transfer ModeBAPTA Bearing and Power TransferAssemblyBCH Broadcast ChannelBCR Battery Charge RegulatorBDR Battery Discharge RegulatorBECN Backward explicit congestionnoticationBEP Bit Error ProbabilityBER Bit Error RateBFN Beam Forming NetworkBFSK Binary Frequency Shift KeyingBGMP Border Gateway MulticastProtocolBGP Border Gateway ProtocolBHCA Busy Hour Call AttemptsBHCR Busy Hour Call RateBISDN Broadband ISDNBIS Broadband Interactive SystemBITE Built-In Test EquipmentBOL Beginning of LifeBPF Band Pass FilterBPSK Binary Phase Shift KeyingBS Base StationBSC Binary SynchronousCommunications (bisync)BSN Block Sequence NumberBSS Broadcasting Satellite ServiceBT Base TransceiverBTS Base Transceiver StationBW BandWidthCAD Computer Aided DesignCAM Computer Aided ManufacturingCAMP Channel AMPlierCATV CAbleTeleVisionCBDS Connectionless broadband dataserviceCBO Continuous Bit OrientedCBR Constant Bit RateCCI CoChannel InterferenceCCIR Comite Consultatif Internationaldes Radiocommunications(International Radio ConsultativeCommittee)CCITT Comite Consultatif International duTelegraphe et du Telephone (TheInternational Telegraph andTelephone Consultative Committee)CCSDS Consultative Committee for SpaceData SystemsCCU Cluster Control UnitCDMA Code Division Multiple AccessCEC Commission of the EuropeanCommunitiesCELP Code Excited Linear PredictionCENELEC Comite Europeen pour laNormalisation en ELECtrotechnique(European Committee for Electro-technical Standardisation)CEPT Conference Europeenne des Postes etTelecommunications (EuropeanConference of Post andTelecommunications)CFDMA Combined Free/DemandAssignment Multiple AccessCFM Companded Frequency ModulationCFRA Combined Fixed/ReservationAssignmentCIR Committed Information RateCIRF Co-channel Interference ReductionFactorCIS Commonwealth of IndependentStatesCLDLS ConnectionLess Data Link ServiceCLEC Competitive Local ExchangeCarrierCLNP ConnectionLess Network ProtocolCLTU Command Link Transmission UnitCMOS Complementary Metal OxideSemiconductorCNES Centre National dEtudes Spatiales(French Space Agency)CODLS Connection Oriented Data LinkServiceCOMETS Communications and BroadcastingEngineering Test SatelliteCONUS CONtinental USCoS Class of ServiceCOST European COoperation in the eld ofScientic and Technical researchCOTS Commercial Off The ShelfCPS Chemical Propulsion SystemCRC Communications Research Centre(Canada)CS Cell SelectionCSMA Carrier Sense Multiple AccessCT Cordless TelephoneCTR Common Technical RegulationCTU Central Terminal UnitD-AMPS Digital Advanced Mobile PhoneSystemD-M-PSK Differential M-ary Phase Shift KeyingD/C Down-ConverterDA Demand AssignmentDAB Digital Audio BroadcastingDAC Digital to Analog ConverterDAMA DemandAssignment Multiple AccessDARPA Defense Advanced Research ProjectDASS Demand Assignment Signalling andSwitchingdB deciBeldBm Unit for expression of power level indB with reference to 1 mWdBm Unit for expression of power level indB with reference to 1 mWdBmO Unit for expression of power level indBm at a point of zero relative level(a point of a telephone channel wherethe 800 Hz test signal has a power of1 mW)DBF Digital Beam FormingDBFN Digital Beam Forming NetworkDBS Direct Broadcasting SatelliteDC Direct CurrentDCCH Dedicated Control ChannelDCE Data Circuit Terminating EquipmentDCFL Direct Coupled Fet LogicDCME Digital Circuit MultiplicationEquipmentDCS Digital Cellular System(GSMAt 1800MHz)DCT Discrete Cosine TransformDCU Distribution Control UnitDDCMP Digital Data CommunicationsMessage Protocol (a DEC Protocol)DE Differentially Encodedxviii AcronymsDE-M-PSK Differentially Encoded M-aryPhase Shift KeyingDECT Digital European CordlessTelephoneDEMOD DEMODulatorDEMUX DEMUltipleXerDES Data Encryption StandardDM Delta ModulationDNS Domain Name Service (host nameresolution protocol)DOD Depth of DischargeDOF Degree of FreedomDQDB Distributed Queue Dual BusDSCP Differentiated Service Code PointDSI Digital Speech InterpolationDSL Digital Subscriber LoopDSP Digital Signal ProcessingDTE Data Terminating EquipmentDTH Direct To HomeDTTL Data Transition Tracking LoopDUT Device Under TestDVB Digital Video BroadcastingDWDM Dense Wave Division MultiplexingEA Early AssignmentEBU European Broadcasting UnionEC European CommunityECL Emitter Coupled LogicEFS Error Free SecondsEIA Electronic Industries AssociationEIR Equipment Identity RegisterEIRP Effective Isotropic RadiatedPower (W)ELSR Edge Label Switch RouterEMC ElectroMagnetic CompatiblityEMF ElectroMagnetic FieldEMI ElectroMagnetic InterferenceEMS European Mobile SatelliteENR Excess Noise RatioEOL End of LifeEPC Electric Power ConditionerEPIRB Emergency Position Indicating RadioBeamERC European RadiocommunicationsCommitteeERL Echo Return LossERO European RadiocommunicationsOfce (of the ERC)ES Earth StationESA European Space AgencyESTEC European Space Research andTechnology CentreETR ETSI Technical ReportETS European TelecommunicationsStandard, created within ETSIETSI European TelecommunicationsStandards InstituteEUTELSAT European TelecommunicationsSatellite OrganisationFAC Final Assembly CodeFCC Federal CommunicationsCommissionFCS Frame Check SequenceFDDI Fibre Distributed Data InterfaceFDM Frequency Division MultiplexFDMA Frequency Division Multiple AccessFEC Forward Error CorrectionFES Fixed Earth StationFET Field Effect TransistorFETA Field Effect Transistor AmplierFFT Fast Fourier TransformFGM Fixed Gain ModeFIFO First In First OutFM Frequency ModulationFMA Fixed-Mount AntennaFMS Fleet Management ServiceFMT Fade Mitigation TechniqueFODA FIFO Ordered Demand AssignmentFPGA Field Programmable Gate ArrayFPLMTS Future Public Land MobileTelecommunications SystemFS Fixed ServiceFR Frame RelayFSK Frequency Shift KeyingFSS Fixed Satellite ServiceFTP File Transfer ProtocolGA ETSI General AssemblyGaAs Gallium ArsenideGBN Go Back NGC Global CoverageGCE Ground CommunicationEquipmentGCS Ground Control StationGDE Group Delay EqualizerGEO Geostationary Earth OrbitGMDSS Global Maritime Distress and SafetySystemGOS Grade Of ServiceGPRS General Packet Radio ServiceGPS Global Positioning SystemGRE Generic Routing EncapsulationGSM Global System for MobilecommunicationsGSO Geostationary Satellite OrbitGTO Geostationary Transfer OrbitHDB3 High Density Binary 3 codeHDLC High Level Data Link ControlHDTV High Denition TeleVisionHEMT High Electron Mobility TransistorHEO Highly Elliptical OrbitHIO Highly Inclined OrbitAcronyms xixHIPERLAN HIgh PErformance Radio Local AreaNetworkHLR Home Location RegisterHPA High Power AmplierHPB Half Power BeamwidthHPT Hand Held Personal TelephoneHTML Hyper Text Markup LanguageHTTP Hyper Text Transfer ProtocolIAT Interarrival TimeIAU International Astronomical UnitIBA Independent Broadcasting AuthorityIBO Input Back-offIBS International Business ServiceICMP Internet Control Message ProtocolICI Interface Control InformationICO Intermediate Circular OrbitIGMP Internet GroupManagement ProtocolIDC Intermediate rate Digital CarrierIDR Intermediate Data RateIDU Interface Data Unit, also. InDoor UnitIEEE Institute of Electrical and ElectronicEngineersIETF Internet Engineering Task ForceI-ETS Interim ETSIF Intermediate FrequencyIFRB International Frequency RegistrationBoardIGMP Internet GroupManagement ProtocolILS International Launch ServicesIM InterModulationIMP Interface Message ProcessorIMP InterModulation ProductIMSI International Mobile SubscriberIdentityIMUX Input MultiplexerIN Intelligent NetworkINIRIC International Non-Ionising RadIationCommitteeINMARSAT International Maritime SatelliteOrganisationINTELSAT International TelecommunicationsSatellite ConsortiumIOR Indian Ocean RegionIOT In Orbit TestIP Internet Protocol (a network layerdatagram protocol)IPA Intermediate Power AmplierIPE Initial Pointing ErrorIPsec IP security policyIRCD Internet Relay Chat Program Server(a teleconferencing application)IRD Internet Resources DatabaseIRD Integrated Receiver DecoderISDN Integrated Services Digital NetworkISC International Switching CenterISL Intersatellite LinkISO International Organisation forStandardisationISS Inter-Satellite ServiceISU Iridium Subscriber UnitITU International TelecommunicationUnionIUS Inertial Upper StageIVOD Interactive Video On DemandIWU InternetWorking UnitJDBC Java Database ConnectivityJPEG Joint Photographic Expert GroupLA Location AreaLAN Local Area NetworkLAPB Link Access Protocol BalancedLDP Label Distribution ProtocolLEO Low Earth OrbitLFSR Linear Feedback Shift RegisterLHCP Left Hand Circular PolarizationLLC Logical Link ControlLLM Lband Land MobileLMDS Local Multipoint Distribution SystemLMSS Land Mobile Satellite ServiceLNA Low Noise AmplierLNB Low Noise BlockLO Local OscillatorLOS Line of SightLPC Linear Predictive CodingLPF Low Pass FilterLR Location RegisterLRE Low Rate EncodingLSP Label Switched PathLSR Label Switching RouterLU Location UpdatingM-PSK M-ary Phase Shift KeyingMAC Medium Access ControlMAC Multiplexed Analog Components(also Monitoring, Alarmand Control)MACSAT Multiple Access SatelliteMAMA Multiple ALOHA Multiple AccessMAN Metropolitan Area NetworkMCPC Multiple Channels Per CarrierMEB Megabit Erlang Bit rateMEO Medium altitude Earth OrbitMES Mobile Earth StationMESFET Metal Semiconductor Field EffectTransistorMF MultifrequencyMHT Mean Holding TimeMIC Microwave Integrated CircuitMIDI Musical Instrument Digital InterfaceMIFR Master International FrequencyRegisterMMDS Multipoint Multichannel DistributionSystemxx AcronymsMMIC Monolithic Microwave IntegratedCircuitMOD MODulatorMODEM Modulator/DemodulatorMOS Mean Opinion ScoreMOS Metal-Oxide SemiconductorMoU Memorandum of UnderstandingMPEG Motion Picture Expert GroupMPLS Multi-Protocol Label SwitchingMPSK M-ary Phase Shift KeyingMS Mobile StationMSC Mobile Switching CenterMSK Minimum Shift KeyingMSS Mobile Satellite ServiceMTBF Mean Time Between FailureMTP Message Transfer PartMTU Maximum Transferable UnitMUX MUltipleXerMX MiXerNACK No ACKnowledgmentNASA National Aeronautics And SpaceAdministration (USA)NASDA National Aeronautics And SpaceDevelopment Agency (Japan)NAT Network Address TranslationNGSO Non-Geostationary Satellite OrbitNH Northern HemisphereNIS Network Information SystemNMT Nordic Mobile TelephoneNNTP Network News Transfer ProtocolNOAA National Oceanic and AtmosphericAdministrationNORM Nack-Oriented Reliable MulticastNSO National StandardisationOrganisationNRZ Non-Return to ZeroNTP Network Time ProtocolNVOD Near Video On DemandOACSU Off-Air Call Set-UpOBC On-Board ComputerOBO Output Back-OffOBP On-Board ProcessingODU Outdoor UnitOICETS Optical Inter-orbit CommunicationsEngineering Test SatelliteOMUX Output MUltipleXerONP Open Network ProvisionOSI Open System InterconnectionOSPF Open Shortest Path FirstPABX Private Automatic Branch eXchangePACS Personal Access CommunicationsSystemPAD Packet Assembler/DisassemblerPAM Payload Assist ModulePB Primary Body (orbits)PBX Private (automatic) Branch eXchangePC Personal ComputerPCCH Physical Control CHannelPCH Paging CHannelPCM Pulse Code ModulationPCN Personal Communications Network(often refers to DCS 1800)PCS Personal Communications SystemPDCH Physical Data CHannelPDF Probability Density FunctionPDH Plesiochronous Digital HierarchyPDU Protocol Data UnitPFD Power Flux DensityPHEMT Pseudomorphic High ElectronMobility TransistorPHB Per Hop BehaviourPHP Personal Handy PhonePHS Personal Handyphone SystemPICH PIlot ChannelPILC Performance Implication of LinkCharacteristicsPIMP Passive InterModulation ProductPKM Perigee Kick MotorPLL Phase Locked LoopPLMN Public Land Mobile NetworkPM Phase ModulationPMR Private Mobile RadioPN Personal NumberPODA Priority Oriented DemandAssignmentPOL POLarisationPOR Pacic Ocean RegionPP Portable PartPPP Point to Point ProtocolPRMA Packet Reservation Multiple AccessPSD Power Spectral DensityPSK Phase Shift KeyingPSPDN Packet SwitchedPublic DataNetworkPSTN Public Switched Telephone NetworkPTA Programme Tracking AntennaPTN Public Telecommunications NetworkPTO Public Telecommunications OperatorPVA Perigee Velocity AugmentationPVC Permanent Virtual CircuitQoS Quality of ServiceQPSK Quaternary Phase Shift KeyingRAAN Right Ascension of the AscendingNodeRACE Research and development inAdvanced CommunicationsRACH Random Access ChannelRADIUS Remote Authentication Dial In UserServiceRAM Random Access MemoryAcronyms xxiRAN Radio Area NetworkRARC Regional Administrative RadioConferenceRAS Radio Astronomy ServiceRCVO Receive OnlyRCVR ReCeiVeRRDS Radio Data SystemRDSS Radio Determination Satellite ServiceRE Radio ExchangeRec RecommendationRep ReportRES Radio Equipment Systems,ETSI Technical CommitteeRF Radio FrequencyRFHMA Random Frequency HoppingMultiple AccessRFI Radio Frequency InterferenceRGS Route Guidance ServiceRHCP Right-Hand Circular PolarizationRIP Routing Information ProtocolRL Return LossRLAN Radio Local Area NetworkRLL Radio in the Local LoopRLOGIN Remote login applicationRMA Random Multiple AccessRMTP Realisable Multicast TransportProtocolRNCC Regional Network Control CenterRNR Receiver Not ReadyRORA Region Oriented Resource AllocationRR Radio RegulationRS Reed Solomon (coding)RSVP Resource reSerVation ProtocolRTCP Real Time transport Control ProtocolRTP Real Time transport ProtocolRTU Remote Terminal UnitRX ReceiverS-ALOHA Slotted ALOHA protocolSAMA Spread ALOHA Multiple AccessSAP Service Access PointSAW Surface Acoustic WaveSB Secondary Body (orbits)SBC Sub-Band CodingSC Suppressed CarrierS/C SpaceCraftSCADA Supervisory Control and DataAcquisitionSCCP Signalling Connection Control PartSCH Synchronization CHannelSCP Service Control PointSCPC Single Channel Per CarrierSDH Synchronous Digital HierarchySDLC Synchronous Data Link ControlSDU Service Data UnitSEP Symbol Error ProbabilitySEU Single Event UpsetSFH Slow Frequency HoppingSH Southern HemisphereSHF Super High Frequency (3 GHz to30 GHz)SIM Subscriber Identity ModuleS-ISUP Satellite ISDN User PartSIT Satellite Interactive TerminalSKW Satellite-Keeping WindowSL SatelLiteSLA Service Level AgreementSLIC Subscriber Line Interface CardSMATV Satellite basedMaster Antenna for TVdistributionSME Small and Medium EnterpriseSMS Satellite Multi-ServicesSMTP Simple Mail Transfer ProtocolSNA Systems Network Architecture (IBM)SNDCP SubNet Dependent ConvergenceProtocolSNEK Satellite NEtworK node computerSNG Satellite News GatheringSNMP Simple Network ManagementProtocolSNR Signal-to-Noise RatioSOC State of ChargeSOHO Small Ofce Home OfceSORA Satellite Oriented ResourceAllocationSORF Start of Receive FrameSOTF Start of Transmit FrameSPADE Single-channel-per-carrier PCMmultiple Access Demand assignmentEquipmentS-PCN Satellite Personal CommunicationsNetworkS/PDIF Sony/Philips Digital InterfaceFormatSPDT Single-Pole Double-Throw (switch)SPMT Single-Pole Multiple-Throw (switch)SPT Stationary Plasma ThrusterSPU Satellite Position UncertaintySR Selective RepeatSS Satellite SwitchSSB Single Side-BandSSMA Spread Spectrum Multiple AccessSSO Sun-Synchronous OrbitSSOG Satellite Systems Operations Guide(INTELSAT)SSP Signalling Switching PointSSPA Solid State Power AmplierSS-TDMA Satellite Switched TDMASTC ETSI Sub-Technical CommitteeSTM Synchronous Transport ModuleSTS Space Transportation SystemSU Subscriber UnitSVC Switched Virtual CircuitSW Switchxxii AcronymsSW Stop and WaitSWR Standing Wave RatioSYNC SYNChronisationTA ETSI Technical AssemblyTACS Total Access Communication SystemTBC To Be ConrmedTBD To Be DenedTBR Technical Basis RegulationT/R Transmit/ReceiveTC TelecommandTCH Trafc CHannelTCP Transmission Control ProtocolTDM Time Division MultiplexTDMA Time Division Multiple AccessTDRS Tracking and Data Relay SatelliteTELNET remote terminal applicationTEM Transverse ElectroMagneticTETRA Trans European Trunk RadioTFTS Terrestrial Flight Telephone SystemTIA Telecommunications IndustryAssociationTIE Terrestrial Interface EquipmentTM TelemetryTM/TC Telemetry/TelecommandTP4 Transport Protocol Class 4TPR TransponderTRAC Technical RecommendationsApplication CommitteeTTC Telemetry, Tracking and CommandTTCM Telemetry, Tracking, Command andMonitoringTTL Transistor Transistor LogicTTL Time To LiveTTY TelegraphYTV TeleVisionTWT Travelling WaveTubeTWTA Travelling WaveTube AmplierTx TransmitterU/C Up-ConverterUDLR UniDirectional Link RoutingUDP User Datagram ProtocolUHF Ultra High Frequency (300 MHz to3 GHz)UMTS Universal MobileTelecommunications SystemUPS Uninterruptible Power SupplyUPT Universal PersonalTelecommunicationsUSAT Ultra Small Aperture TerminalUSB Universal Serial BusUW Unique WordVBR Variable Bit RateVC Virtual Channel (or Container)VCI Virtual Channel IdentierVDSL Very high-speed DigitalSubscriber LineVHDL VHSIC Hardware DescriptionLanguageVHSIC Very High Speed IntegratedCircuitVHF Very High Frequency (30 MHz to300 MHz)VLR Visitor Location RegisterVLSI Very Large Scale IntegrationVOW Voice Order WireVPA Variable Power AttenuatorVPC Virtual Path ConnectionVPD Variable Phase DividerVPS Variable Phase ShifterVPI Virtual Path IdentierVPN Virtual Private NetworkVSAT Very Small ApertureTerminalVSELP Vector Sum Excitation LinearPredictionVSWR Voltage Standing Wave RatioWAN Wide Area NetworkWAP Wireless Application ProtocolWARC World Administrative RadioConferenceWeb Worldwide WebXPD Cross PolarizationDiscriminationXPI Cross Polarisation IsolationXponder TransponderAcronyms xxiiiNOTATIONa orbit semi-major axisA azimuth angle (also attenuation, area,availability, trafc density and carrieramplitude)Aeff effective aperture area of an antennaAAG attenuation by atmospheric gasesARAIN attenuation due to precipitation andcloudsAP attenuation of radiowave by rain forpercentage p of an average yearB bandwidthb voice channel bandwidth (3100 Hz from300 to 3400 Hz)Bn noise measurement bandwidth atbaseband (receiver output)BN equivalent noise bandwidth ofreceiverBu burstinessc velocity of light 3 108m=sC carrier powerC=N0 carrier power-to-noise power spectraldensity ratio (W/Hz)C=N0U uplink carrier power-to-noise powerspectral density ratioC=N0D downlink carrier power-to-noise powerspectral density ratioC=N0IM carrier power-to-intermodulation noisepower spectral density ratioC=N0I carrier power-to-interference noisepower spectral density ratioC=N0I;U uplink carrier power-to-interferencenoise power spectral density ratioC=N0I;D downlink carrier power-to-interferencenoise power spectral density ratioC=N0T carrier power-to-noise power spectraldensity ratio for total linkD diameter of a reector antenna (also usedas a subscript for downlink)e orbit eccentricityE elevation angle (also energy and electriceld strength)Eb energy per information bitEc energy per channel bitf frequency (Hz)Fc nominal carrier frequencyfd antenna focal lengthfm frequency of a modulating sine wavefmax maximum frequency of the modulatingbaseband signal spectrumfD downlink frequencyfU uplink frequencyF noise gureDFmax peak frequency deviation of a frequencymodulated carrierfS sampling frequencyg peak factorG power gain (also gravitational constant)Gsat gain at saturationGR receiving antenna gain in direction oftransmitterGT transmitting antenna gain in direction ofreceiverGRmax maximum receiving antenna gainGTmax maximum transmitting antenna gainGSR satellite repeater gainGSRsat saturation gain of satellite repeaterG/T gain to systemnoise temperature ratio ofa receiving equipmentGCA channel amplierGFE front end gain from satellite receiverinput to satellite channel amplier inputGss small signal power gaini inclination of the orbital planek Boltzmanns constant 1:379 1023W=KHzkFM FM modulation frequency deviationconstant (MHz/V)kPM PM phase deviation constant (rad/V)KP AM/PM conversion coefcientKT AM/PM transfer coefcientl earth station latitudeL earth station-to-satellite relativelongitude also loss in link budgetcalculations, and loading factor of FDM/FM multiplex also message length (bits)Le effective path length of radiowavethrough rain (km)LFRX receiver feeder lossLFTX transmitter feeder lossLFS free space lossLPOINT depointing lossLPOL antenna polarisation mismatch lossLR receiving antenna depointing lossLT transmitting antenna depointing lossm satellite massmc power reduction associated withmulticarrier operationM mass of the earth (kg) (also number ofpossible states of a digital signal)N0 noise power spectral density (W/Hz)N0U uplink noise power spectral density(W/Hz)N0D downlink noise power spectral density(W/Hz)N0T total link noise power spectral density(W/Hz)N0I interference power spectral density(W/Hz)N noise power (W) (also number of stationsin a network)p pre-emphasis/compandingimprovement factor (also rainfallannual percentage)pw rainfall worst month time percentageP power (also number of bursts in a TDMAframe)Pb information bit error ratePc channel bit error ratePHPA rated power of high power amplier (W)PT power fed to the antenna (W)PTx transmitter power (W)PR received power (W)PRx power at receiver input (W)Pis input power in a single carrier operationmodePo 1 output power in a single carrieroperation mode(Pi 1)sat input power in a single carrier operationmode at saturation(Po 1)sat saturation output power in a singlecarrier operation modePi n input power in a multiple carrieroperation mode (n carriers)Po n output power in a multiple carrieroperation mode (n carriers)PIMX n power of intermodulation product oforder X at output of a non-linear devicein a multicarrier operation mode(n carriers)Q quality factorr distance between centre of mass (orbits)R slant range from earth station to satellite(km) (also symbol or bit rate)Rb information bit rate (s1)Rc channel bit rate (s1)Rcall mean number of calls per unit timeRE earth radius 6378 kmRo geostationary satellitealtitude 35 786 kmRp rainfall rate (mm/h) exceeded for timepercentage p of a yearRs symbol (or signalling) rate (s1)S user signal power (W)S/N signal-to-noise power ratio at users endT period of revolution (orbits) (s)(also noise temperature (K))TA antenna noise temperature (K)TAMB ambient temperature (K)Tb information bit duration (s)TB burst duration (s)Tc channel bit duration (s)Te effective input noise temperature of afour port element system (K)TE mean sidereal day 86164:15TeATT effective input noise temperature of anattenuator (K)TeRx effective input noise temperature of areceiverTF frame duration (s) (also feedertemperature)Tm effective medium temperature (K)T0 reference temperature (290 K)TeRX effective input noise temperature of areceiver (K)TS symbol duration (s)TSKY clear key contribution to antenna noisetemperature (K)TGROUND ground contribution to antenna noisetemperature (K)U subscript for uplinkv true anomaly (orbits)Vs satellite velocity (m/s)xxvi NotationVLp/p peak-to-peak luminance voltage (V)VTp/p peak-to-peak total video signal voltage(including synchronisation pulses)VNms root-mean-square noise voltage (V)w psophometric weighting factorX intermodulation product order (IMX)a angle from boresight of antennag vernal pointG spectral efciency (bit/s Hz)d declination angle (also delay)h antenna aperture efciencyl wavelength ( c=f ) also longitude, alsomessage generation rate (s1)w latitudet propagation timeu3dB half power beamwidth of an antennawavelength c=fuR receiving antenna pointing erroruT transmit antenna pointing errorm GMG gravitational constant,M mass of earth;G 6:67 1011m3kg1s2,M 5:974 1024kg;m GM 3:986 1014m3s2r code rates StefanBoltzmann constant 5:67 108Wm2K4f satelliteearth station angle from theearths centreF power ux density (w/m2)Fmax max maximum power ux density attransmit antenna boresightFnom nom nominal power ux densityat receive end required to build upa given power assuming maximumreceive gain (no depointing)Fsat power ux density required to operatereceive amplier at saturationc polarisation anglev argument of perigeeW right ascension of the ascendingnodeWE angular velocity of rotation of the earthearth 15:0469 deg=hr 4:17103deg=s7:292105rad=sNotation xxvii1 INTRODUCTIONThis chapter describes the characteristics of satellite communication systems. It aims to satisfythe curiosity of an impatient reader and facilitate a deeper understanding by directing him or herto appropriate chapters without imposing the need to read the whole work frombeginning to end.1.1 BIRTH OF SATELLITE COMMUNICATIONSSatellite communications are the outcome of research in the area of communications and spacetechnologies whose objective is to achieve ever increasing ranges and capacities with the lowestpossible costs.The Second World War stimulated the expansion of two very distinct technologiesmissilesand microwaves. The expertise eventually gained in the combined use of these two techniquesopened up the era of satellite communications. The service provided in this way usefullycomplements that previously provided exclusively by terrestrial networks using radio and cables.The space era started in 1957 with the launching of the rst articial satellite (Sputnik).Subsequent years have been marked by various experiments including the following: Christmasgreetings from President Eisenhower broadcast by SCORE (1958), the reecting satellite ECHO(1960), store-and-forward transmission by the COURIER satellite (1960), powered relay satellites(TELSTAR and RELAY in 1962) and the rst geostationary satellite SYNCOM (1963).In 1965, the rst commercial geostationary satellite INTELSAT I (or Early Bird) inauguratedthe long series of INTELSATs; in the same year, the rst Soviet communications satellite of theMOLNYA series was launched.1.2 DEVELOPMENT OF SATELLITE COMMUNICATIONSThe rst satellites provided a low capacity at a relatively high cost; for example, INTELSAT Iweighed 68 kg at launch for a capacity of 480 telephone channels and an annual cost of $32 500 perchannel at the time. This cost resulted from a combination of the cost of the launcher, that of thesatellite, the short lifetime of the satellite (1.5 years) and its low capacity. The reduction in cost isthe result of much effort which has led to the production of reliable launchers which can putheavier and heavier satellites into orbit (typically 5900 kg at launch in 1975, reaching 10 500 kg byAriane 5 ECA and 13 000 kg by Delta IV in 2008). In addition, increasing expertise in microwavetechniques has enabled realisation of contoured multibeam antennas whose beams adapt to theshape of continents, frequency re-use from one beam to the other and incorporation of higherSatellite Communications Systems, Fifth Edition Gerard Maral, Michel Bousquet and Zhili Sun 2009 John Wiley & Sons, Ltd.power transmission ampliers. Increased satellite capacity has led to a reduced cost per telephonechannel.In addition to the reduction in the cost of communication, the most outstanding feature is thevariety of services offered by satellite communications systems. Originally these were designedto carry communications from one point to another, as with cables, and the extended coverage ofthe satellite was used to set up long distance links; hence Early Bird enabled stations on oppositesides of the Atlantic Ocean to be connected. However, as a consequence of the limitedperformanceof the satellite, it was necessary to use earth stations equippedwith large antennas and therefore ofhigh cost (around $10 million for a station equipped with a 30m diameter antenna).The increasing size and power of satellites has permitted a consequent reduction in the size ofearth stations, and hence their cost, leading to an increase in number. In this way it has beenpossible to exploit another feature of the satellite which is its ability to collect or broadcast signalsfromor to several locations. Insteadof transmitting signals fromone point to another, transmissioncan be from a single transmitter to a large number of receivers distributed over a wide area or,conversely, transmission can be from a large number of stations to a single central station, oftencalled a hub. In this way, multipoint data transmission networks and data collection networkshave beendevelopedunder the name of VSAT(verysmall aperture terminals) networks [MAR-95].Over 1 000 000 VSATs have been installed up to 2008. For TV services, satellites are of paramountimportance for satellite news gathering (SNG), for the exchange of programmes between broad-casters, for distributing programmes to terrestrial broadcasting stations and cable heads,or directly to the individual consumer. The latter are commonly called direct broadcasting bysatellite (DBS) systems, or direct-to-home (DTH) systems. A rapidly growing service is digitalvideo broadcasting by satellite (DVB-S), developed in early 1991; the standard for the secondgeneration (DVB-S2) has been standardised by the European Telecommunication StandardInstitute (ETSI). These DBS systems operate with small earth stations having antennas with adiameter from 0.5 to 1 m.In the past, the customer stations were Receive Only (RCVO) stations. With the introduction oftwo-way communications stations, satellites are a key component in providing interactive TVand broadband Internet services thanks to the implementation of the DVB satellite return channel(DVB-RCS) standard to the service providers facilities. This uses TCP/IP to support Internet,multicast and web-page caching services over satellite with forward channel operating at severalMbit/s and enables satellites to provide broadband service applications for the end user, such asdirect access and distribution services. IP-based triple-play services (telephony, Internet and TV)are more and more popular. Satellites cannot compete with terrestrial Asymmetric DigitalSubscriber Line (ADSL) or cable to deliver these services in high-density population areas.However, they complement nicely the terrestrial networks around cities and in rural areas whenthe distance to the telephone router is too large to allow delivery of the several Mbit/s required torun the service.A further reduction in the size of the earth station antenna is exemplied in digital audiobroadcasting (DAB) systems, with antennas in the order of 10 cm. The satellite transmits multi-plexed digital audio programmes and supplements traditional Internet services by offering one-way broadcast of web-style content to the receivers.Finally, satellites are effective inmobile communications. Since the endof the 1970s, INMARSATsatellites have been providing distress signal services along with telephone and data commu-nications services to ships and planes and, more recently, communications to portable earthstations (Mini M or Satphone). Personal mobile communication using small handsets is availablefrom constellations of non-geostationary satellites (such as Iridium and Globalstar) and geosta-tionary satellites equipped with very large deployable antennas (typically 10 to 15 m) as with theTHURAYA, ACES, and INMARSAT 4 satellites. The next step in bridging the gaps between xed,mobile and broadcasting radiocommunications services concerns satellite multimedia broadcastto xed and mobile users. Satellite digital mobile broadcasting (SDMB) is based on hybridintegrated satelliteterrestrial systems to serve small hand-held terminals with interactivity.2 Introduction1.3 CONFIGURATION OF A SATELLITECOMMUNICATIONS SYSTEMFigure 1.1 gives an overview of a satellite communication system and illustrates its interfacingwith terrestrial entities. The satellite systemis composedof a space segment, a control segment anda ground segment:The space segment contains one or several active andspare satellites organisedinto a constellation.The control segment consists of all groundfacilities for the control andmonitoringof the satellites,also named TTC (tracking, telemetry and command) stations, and for the management of thetrafc and the associated resources on-board the satellite.Figure 1.1 Satellite communications system, interfacing with terrestrial entities.Conguration of a Satellite Communications System 3The ground segment consists of all the trafc earth stations. Depending on the type of serviceconsidered, these stations can be of different size, from a few centimetres to tens of metres.Table 1.1 gives examples of trafc earth stations in connection with the types of service discussedin Section 1.7. Earth stations come in three classes as illustrated in Figure 1.1: user stations, such ashandsets, portables, mobile stations and very small aperture terminals (VSATs), which allow thecustomer direct access to the space segment; interface stations, known as gateways, which inter-connect the space segment to a terrestrial network; and service stations, such as hub or feederstations, which collect or distribute information from and to user stations via the space segment.Communications between users are set up through user terminals which consist of equipmentsuch as telephone sets, fax machines and computers that are connected to the terrestrial networkor to the user stations (e.g. a VSAT), or are part of the user station (e.g. if the terminal is mobile).The path from a source user terminal to a destination user terminal is named a simplexconnection. There are two basic schemes: single connection per carrier (SCPC), where the modulatedcarrier supports one connection only, and multiple connections per carrier (MCPC), where themodulated carrier supports several time or frequency multiplexed connections. Interactivitybetween two users requires a duplex connection between their respective terminals, i.e. twosimplex connections, each along one direction. Each user terminal should then be capable ofsending and receiving information.Aconnection between a service provider and a user goes through a hub (for collecting services)or a feeder station (e.g. for broadcasting services). A connection from a gateway, hub or feederstation to a user terminal is called a forward connection. The reverse connection is the returnconnection. Both forward and return connections entail an uplink and a downlink, and possiblyone or more intersatellite links.1.3.1 Communications linksA link between transmitting equipment and receiving equipment consists of a radio or opticalmodulated carrier. The performance of the transmitting equipment is measured by its effectiveisotropic radiated power (EIRP), which is the power fed to the antenna multiplied by the gain of theantenna in the considered direction. The performance of the receiving equipment is measuredby G/T, the ratio of the antenna receive gain, G, in the considered direction and the system noisetemperature, T; G/T is called the receivers gure of merit. These concepts are detailed in Chapter 5.The types of link shown in Figure 1.1 are:the uplinks from the earth stations to the satellites;the downlinks from the satellites to the earth stations;the intersatellite links, between the satellites.Table 1.1 Services from different types of trafc earth stationType of service Type of earth station Typical size (m)Point-to-point Gateway, hub 210VSAT 12Broadcast/multicast Feeder station 15VSAT 0.51.0Collect VSAT 0.11.0Hub 210Mobile Handset, portable, mobile 0.10.5Gateway 2104 IntroductionUplinks anddownlinks consist of radio frequencymodulatedcarriers, while intersatellite links canbe either radio frequency or optical. Carriers are modulated by baseband signals conveyinginformation for communications purposes.The link performance can be measured by the ratio of the received carrier power, C, to the noisepower spectral density, N0, and is denoted as the C/N0 ratio, expressed in hertz (Hz). The valuesof C/N0, for the links which participate in the connection between the end terminals, determinethe quality of service, specied in terms of bit error rate (BER) for digital communications.Another parameter of importance for the design of a link is the bandwidth, B, occupied bythe carrier. This bandwidth depends on the information data rate, the channel coding rate(forward error correction) and the type of modulation used to modulate the carrier. For satellitelinks, the trade-off between required carrier power and occupied bandwidth is paramount tothe cost-effective design of the link. This is an important aspect of satellite communications aspower impacts both satellite mass and earth station size, and bandwidth is constrained byregulations. Moreover, a service provider who rents satellite transponder capacity from thesatellite operator is charged according to the highest share of either power or bandwidthresource available from the satellite transponder. The service providers revenue is based onthe number of established connections, so the objective is to maximise the throughput of theconsidered link while keeping a balanced share of power and bandwidth usage. This is discussedin Chapter 4.In a satellite system, several stations transmit their carriers to a given satellite, therefore thesatellite acts as a network node. The techniques used to organise the access to the satellite by thecarriers are called multiple access techniques (Chapter 6).1.3.2 The space segmentThe satellite consists of the payload and the platform. The payload consists of the receiving andtransmitting antennas and all the electronic equipment which supports the transmission of thecarriers. The two types of payload organisation are illustrated in Figure 1.2.Figure 1.2a shows a transparent payload (sometimes called a bent pipe type) where carrierpower is amplied and frequency is downconverted. Power gain is of the order of 100130 dB,required to raise the power level of the received carrier from a few tens of picowatts to the powerlevel of the carrier fed to the transmit antenna of a few watts to a few tens of watts. Frequencyconversion is required to increase isolation between the receiving input and the transmittingoutput. Due to technology power limitations, the overall satellite payload bandwidth is split intoseveral sub-bands, the carriers in each sub-band being amplied by a dedicated power amplier.The amplifying chainassociatedwitheachsub-bandis calleda satellite channel, or transponder. Thebandwidth splitting is achieved using a set of lters called the input multiplexer (IMUX). Theamplied carriers are recombined in the output multiplexer (OMUX).The transparent payload in Figure 1.2a belongs to a single beam satellite where each transmitand receive antenna generates one beam only. One could also consider multiple beam antennas.The payload would then have as many inputs/outputs as upbeams/downbeams. Routing ofcarriers from one upbeam to a given downbeam implies either routing through different satellitechannels, transponder hopping, depending on the selected uplink frequency or on-board switchingwith transparent on-board processing. These techniques are presented in Chapter 7.Figure 1.2b shows a multiple beam regenerative payload where the uplink carriers are demo-dulated. The availability of the baseband signals allows on-board processing and routing ofinformation from upbeam to downbeam through on-board switching at baseband. The frequencyconversion is achieved by modulating on-board-generated carriers at downlink frequency. Themodulated carriers are then amplied and delivered to the destination downbeam.Figure 1.3 illustrates a multiple beam satellite antenna and its associated coverage areas.Each beam denes a beam coverage area, also called footprint, on the earth surface. The aggregateConguration of a Satellite Communications System 5beam coverage areas dene the multibeam antenna coverage area. Agiven satellite may have severalmultiple beam antennas, and their combined coverage denes the satellite coverage area.Figure 1.4 illustrates the concept of instantaneous systemcoverage and long-termcoverage. Theinstantaneous system coverage consists of the aggregation at a given time of the coverage areas ofthe individual satellites participating in the constellation. The long-term coverage is the area on theearth scanned over time by the antennas of the satellites in the constellation.The coverage area should encompass the service zone, which corresponds to the geographicalregion where the stations are installed. For real-time services, the instantaneous system coverageFigure 1.2 Payload organisation: (a) transparent and (b) regenerative.6 IntroductionFigure 1.4 Types of coverage.beam coveragemultibeam antennacoverageSatellite antennaFigure 1.3 Multiple beam satellite antenna and associated coverage area.Conguration of a Satellite Communications System 7should at any time have a footprint covering the service zone, while for non-real-time (store-and-forward) services, it should have long-term coverage of the service zone.The platform consists of all the subsystems which permit the payload to operate. Table 1.2 liststhese subsystems and indicates their respective main functions and characteristics.The detailed architecture and technology of the payload equipment are explained in Chapter 9.The architecture and technologies of the platform are considered in Chapter 10. The operationsof orbit injection and the various types of launcher are the subject of Chapter 11. The spaceenvironment and its effects on the satellite are presented in Chapter 12.To ensure a service with a specied availability, a satellite communication system must makeuse of several satellites in order to ensure redundancy. Asatellite can cease to be available due to afailure or because it has reached the end of its lifetime. In this respect it is necessary to distinguishbetween the reliability and the lifetime of a satellite. Reliability is a measure of the probability ofa breakdown and depends on the reliability of the equipment and any schemes to provideredundancy. The lifetime is conditioned by the ability to maintain the satellite on station in thenominal attitude, and depends on the quantity of fuel available for the propulsion system andattitude and orbit control. In a system, provision is generally made for an operational satellite,a backup satellite in orbit and a backup satellite on the ground. The reliability of the systemwill involve not only the reliability of each of the satellites but also the reliability of launching.An approach to these problems is treated in Chapter 13.1.3.3 The ground segmentThe ground segment consists of all the earth stations; these are most often connected to the end-users terminal by a terrestrial network or, in the case of small stations (Very Small ApertureTerminal, VSAT), directly connected to the end-users terminal. Stations are distinguished by theirsize which varies according to the volume of trafc to be carried on the satellite link and the typeof trafc (telephone, television or data). In the past, the largest were equipped with antennas of30 m diameter (Standard A of the INTELSAT network). The smallest have 0.6 m antennas(receiving stations from direct broadcasting satellites) or even smaller (0.1 m) antennas (mobilestations, portable stations or handsets). Some stations bothtransmit andreceive. Others are receive-only (RCVO) stations; this is the case, for example, with receiving stations for a broadcastingsatellite system or a distribution system for television or data signals. Figure 1.5 shows the typicalarchitecture of an earth station for both transmission and reception. Chapter 5 introducesthe characteristic parameters of the earth station which appear in the link budget calculations.Chapter 3 presents the characteristics of signals supplied to earth stations by the user terminaleither directly or through a terrestrial network, the signal processing at the station (such as sourcecoding and compression, multiplexing, digital speech interpolation, channel coding, scramblingTable 1.2 Platform subsystemSubsystem Principal functions CharacteristicsAttitude and orbit control(AOCS)Attitude stabilisation, orbitdeterminationAccuracyPropulsion Provision of velocity increments Specic impulse, mass ofpropellantElectric power supply Provision of electrical energy Power, voltage stabilityTelemetry, tracking andcommand (TTC)Exchange of housekeepinginformationNumber of channels, security ofcommunicationsThermal control Temperature maintenance Dissipation capabilityStructure Equipment support Rigidity, lightness8 Introductionand encryption), and transmission and reception (including modulation and demodulation).Chapter 8 treats the organisation and equipment of earth stations.1.4 TYPES OF ORBITThe orbit is the trajectory followed by the satellite. The trajectory is within a plane and shaped asan ellipse with a maximum extension at the apogee and a minimum at the perigee. The satellitemoves more slowly in its trajectory as the distance from the earth increases. Chapter 2 providesa denition of the orbital parameters.The most favourable orbits are as follows:Elliptical orbits inclined at an angle of 64

with respect to the equatorial plane. This type of orbitis particularly stable with respect to irregularities in terrestrial gravitational potential and,owing to its inclination, enables the satellite to cover regions of high latitude for a large fractionof the orbital period as it passes to the apogee. This type of orbit has been adopted by the USSRfor the satellites of the MOLNYAsystemwith periodof 12 hours. Figure 1.6 shows the geometryof the orbit. The satellite remains above the regions located under the apogee for a time intervalof the order of 8 hours. Continuous coverage can be ensured with three phased satellites ondifferent orbits. Several studies relate to elliptical orbits with a period of 24 h (TUNDRA orbits)or a multiple of 24 h. These orbits are particularly useful for satellite systems for communicationwith mobiles where the masking effects caused by surrounding obstacles such as buildingsand trees and multiple path effects are pronounced at low elevation angles (say less than 30

).Antenna axisElevation angle ELocal horizonBaseband signals(from users)Baseband signals(to users)POWERSUPPLYTRACKINGMONITORING&CONTROLDIPLEXERIFMODULATORIFDEMODULATORRF FRONT END(low noise amp)RFHIGH POWERAMPLIFIERFigure 1.5 The organisation of an earth station. RFradio frequency, IFintermediate frequency.Types of Orbit 9In fact, inclined elliptic orbits can provide the possibility of links at medium latitudes whenthe satellite is close to the apogee with elevation angles close to 90

; these favourable conditionscannot be provided at the same latitudes by geostationary satellites. In the late 1980s, theEuropean Space Agency (ESA) studied the use of elliptical highly inclined orbits (HEO) fordigital audio broadcasting (DAB) and mobile communications in the framework of its Archi-medes programme. The concept became reality at the end of the 1990s with the Sirius systemdelivering satellite digital audio radio services to millions of subscribers (mainly automobiles)in the United States using three satellites on HEO Tundra-like orbits [AKT-08].Circular low earth orbits (LEO). The altitude of the satellite is constant and equal to severalhundreds of kilometres. The period is of the order of one and a half hours. With near 90

inclination, this type of orbit guarantees worldwide long term coverage as a result of thecombined motion of the satellite and earth rotation, as shown in Figure 1.7. This is the reason forchoosing this type of orbit for observation satellites (for example, the SPOT satellite: altitude830 km, orbit inclination98.7

, period101 minutes). One canenvisage the establishment of store-and-forward communications if the satellite is equipped with a means of storing information.A constellation of several tens of satellites in low altitude (e.g. IRIDIUM with 66 satellites at780 km) circular orbits can provide worldwide real-time communication. Non-polar orbitswith less than 90

inclination, can also be envisaged. For instance the GLOBALSTAR constella-tion incorporates 48 satellites at 1414 km with 52

orbit inclination.Figure 1.6 The orbit of a MOLNYA satellite.10 IntroductionCircular medium earth orbits (MEO), also called intermediate circular orbits (ICO), havean altitude of about 10 000 km and an inclination of about 50

. The period is 6 hours. Withconstellations of about 10 to 15 satellites, continuous coverage of the world is guaranteed,allowing worldwide real-time communications. A planned system of this kind was the ICOsystem (which emerged from Project 21 of INMARSAT but was not implemented) with aconstellation of 10 satellites in two planes at 45

inclination.Circular orbits with zero inclination (equatorial orbits). The most popular is the geostationarysatellite orbit; the satellite orbits around the earth in the equatorial plane according to the earthrotation at an altitude of 35 786 km. The period is equal to that of the rotation of the earth. Thesatellite thus appears as a point xed in the sky and ensures continuous operation as a radiorelay in real time for the area of visibility of the satellite (43% of the earths surface).Hybrid systems. Some systems may include combinations of orbits with circular and ellipticalorbits. Such a design was envisaged for the ELLIPSO system.The choice of orbit depends on the nature of the mission, the acceptable interference and theperformance of the launchers:The extent and latitude of the area to be covered; contrary to widespread opinion, the altitude ofthe satellite is not a determining factor in the link budget for a given earth coverage. Chapter 5shows that the propagation attenuation varies as the inverse square of the distance and thisfavours a satellite following a low orbit on account of its low altitude; however, this disregardsthe fact that the area to be covered is then seen through a larger solid angle. The result isa reduction in the gain of the satellite antenna which offsets the distance advantage. Now asatellite following a low orbit provides only limited earth coverage at a given time and limitedtime at a given location. Unless low gain antennas (of the order of a few dB) which providelowdirectivity and hence almost omnidirectional radiation are installed, earth stations must beFigure 1.7 Circular polar low earth orbit (LEO).Types of Orbit 11equippedwith satellite tracking devices which increase the cost. The geostationary satellite thusappears to be particularly useful for continuous coverage of extensive regions. However, it doesnot permit coverage of the polar regions which are accessible by satellites in inclined ellipticalorbits or polar orbits.The elevation angle; a satellite in an inclined or polar elliptical orbit can appear overhead atcertain times which enables communication to be established in urban areas without encoun-tering the obstacles which large buildings constitute for elevation angles between 0

andapproximately 70

. With a geostationary satellite, the angle of elevation decreases as thedifference in latitude or longitude between the earth station and the satellite increases.Transmission duration and delay; the geostationary satellite provides a continuous relay forstations within visibility but the propagation time of the waves from one station to the other isof the order of 0.25 s. This requires the use of echo control devices on telephone channels orspecial protocols for data transmission. A satellite moving in a low orbit confers a reducedpropagation time. The transmission time is thus low between stations which are close andsimultaneously visible to the satellite, but it can become long (several hours) for distant stationsif only store-and-forward transmission is considered.Interference; geostationarysatellites occupyxedpositions inthe skywithrespect tothe stationswith which they communicate. Protection against interference between systems is ensured byplanning the frequency bands and orbital positions. The small orbital spacing between adjacentsatellites operating at the same frequencies leads to an increase in the level of interferenceand this impedes the installation of new satellites. Different systems could use differentfrequencies but this is restricted by the limited number of frequency bands assigned for spaceradiocommunications by the Radiocommunication Regulations. In this context, one can refer toan orbit-spectrum resource which is limited. With orbiting satellites, the geometry of eachsystem changes with time and the relative geometries of one system with respect to anotherare variable and difcult to synchronise. The probability of interference is thus high.The performance of launchers; the mass which can be launched decreases as the altitudeincreases.The geostationary satellite is certainly the most popular. At the present time there are around600 geostationary satellites in operation within the 360

of the whole orbital arc. Some parts of thisorbital arc, however, tend to be highly congested (for example above the American continent andEurope).1.5 RADIO REGULATIONSRadio regulations are necessary to ensure an efcient and economical use of the radio-frequencyspectrum by all communications systems, both terrestrial and satellite. While so doing, thesovereign right of each state to regulate its telecommunication must be preserved. It is the roleof the International Telecommunication Union (ITU) to promote, coordinate and harmonisethe efforts of its members to full these possibly conicting objectives.1.5.1 The ITU organisationThe International Telecommunication Union (ITU), a United Nations organ, operates under aconvention adopted by its member administrations. The ITU publishes the RadiocommunicationRegulations (RR), which are reviewed by the delegates from ITU member administrations atperiodic World/Regional Radio Conferences (WRC/RRC).From1947 to 1993 the technical and operational matters were administrated by two committees:the CCIR (Comite Consultatif International des Radiocommunications) and the CCITT (Comite12 IntroductionConsultatif International Telegraphique et Telephonique). The International Frequency Registra-tion Board (IFRB) was responsible for the examination of frequency-use documentation submittedto the ITU by its member administrations, in compliance with the Radiocommunication Regula-tions, and for maintaining the Master International Frequency Register (MIFR).Since 1994 the ITU has been reorganised into three sectors:The Radiocommunications Sector (ITU-R) deals with all regulatory and technical matters thatwere previously handled respectively by the IFRB and the CCIR.The Telecommunication Standardisation Sector (ITU-T) continues the work of the CCITT, andthose studies by the CCIR dealing with the interconnection of radiocommunications systemswith public networks.The Development Sector (ITU-D) acts as a forumand an advisory structure for the harmoniousdevelopment of communications in the world.The abundant and useful technical literature previously published in the form of reports andrecommendations bythe CCIRandthe CCITThave nowbeenreorganisedinthe formof ITU-RandITU-T series recommendations.1.5.2 Space radiocommunications servicesThe Radiocommunication Regulations refer to the following space radiocommunicationsservices, dened as transmission or reception of radio waves for specic telecommunicationsapplications:Fixed Satellite Service (FSS);Mobile Satellite Service (MSS);Broadcasting Satellite Service (BSS);Earth Exploration Satellite Service (EES);Space Research Service (SRS);Space Operation Service (SOS);Radiodetermination Satellite Service (RSS);Inter-Satellite Service (ISS);Amateur Satellite Service (ASS).1.5.3 Frequency allocationFrequency bands are allocated to the above radiocommunications services to allow compatibleuse. The allocated bands can be either exclusive for a given service, or shared among severalservices. Allocations refer to the following division of the world into three regions:region 1: Europe, Africa, the Middle East, the former USSR;region 2: the Americas;region 3: Asia Pacic, except the Middle East and the former USSR.For example, the xed satellite service makes use of the following bands:Around 6 GHz for the uplink and around 4 GHz for the downlink (systems described as6/4 GHz or C band). These bands are occupied by the oldest systems (such as INTELSAT,American domestic systems etc.) and tend to be saturated.Radio Regulations 13Around 8 GHz for the uplink and around 7 GHz for the downlink (systems described as8/7 GHz or X band). These bands are reserved, by agreement between administrations, forgovernment use.Around 14 GHz for the uplink and around 12 GHz for the downlink (systems described as14/12 GHz or Ku band). This corresponds to current operational developments (such asEUTELSAT, etc.).Around 30 GHz for the uplink and around 20 GHz for the downlink (systems described as30/20 GHz or Ka band). These bands are raising interest due to large available bandwidth andlittle interference due to present rather limited use.The bands above 30 GHz will be used eventually in accordance with developing requirementsand technology. Table 1.3 summarises the above discussion.The mobile satellite service makes use of the following bands:VHF (very high frequency, 137138 MHz downlink and 148150 MHz uplink) and UHF (ultrahigh frequency, 400401 MHz downlink and 454460 MHz uplink). These bands are for non-geostationary systems only.About 1.6 GHz for uplinks and 1.5 GHz for downlinks, mostly used by geostationary systemssuch as INMARSAT; and 16101626.5 MHz for the uplink of non-geostationary systems such asGLOBALSTAR.About 2.2 GHz for downlinks and 2 GHz for uplinks for the satellite component of IMT2000(International Mobile Telecommunications).About 2.6 GHz for uplinks and 2.5 GHz for downlinks.Frequency bands have also been allocated at higher frequencies such as Ka band.The broadcasting satellite service makes use of downlinks at about 12 GHz. The uplink is operatedin the FSS bands and is called a feeder link. Table 1.3 summarises the main frequency allocation andindicates the correspondence with some usual terminology.1.6 TECHNOLOGY TRENDSThe start of commercial satellite telecommunications can be traced back to the commissioningof INTELSAT I (Early Bird) in 1965. Until the beginning of the 1970s, the services provided weretelephone and television (TV) signal transmission between continents. The satellite was designedtocomplement the submarine cable andplayedessentiallythe role of a telephone trunkconnection.Table 1.3 Frequency allocationsRadiocommunications serviceTypical frequency bandsfor uplink/downlink Usual terminologyFixed satellite service (FSS) 6/4 GHz C band8/7 GHz X band14/1211 GHz Ku band30/20 GHz Ka band50/40 GHz V bandMobile satellite service (MSS) 1.6/1.5 GHz L band30/20 GHz Ka bandBroadcasting satellite service (BSS) 2/2.2 GHz S band12 GHz Ku band2.6/2.5 GHz S band14 IntroductionThe goal of increased capacity has led rapidly to the institution of multibeam satellites and there-use of frequencies rst by orthogonal polarisation and subseqently by angular separation(see Chapter 5). Communicationtechniques (see Chapter 4) have changedfromanalogue to digital.The second-generation DVB-S2, although backward compatible with DVB-S, has made use of themany novel technologies developed in recent years, including modulation techniques of 8PSK,16 and32 APSKinadditiontoQPSK; efcient forwarderror correction(FEC) withnewlow-densityparitycheck(LDPC) codes; adaptive codingandmodulations (ACM); andperformance close totheShannon limit. This makes DVB-S2 30% more efcient than DVB-S. DVB-RCS can provide up to20 Mbit/s forward link to user terminal and 5 Mbit/s return link from user terminal, which iscomparable to ADSL technology. Multiple access to the satellite (see Chapter 6) was resolved byfrequency division multiple access (FDMA). The increasing demand for a large number of lowcapacity links, for example for national requirements or for communication with ships, led in 1980to the introduction of demand assignment (see Chapter 6) rst using FDMA with single channelper carrier/frequency modulation (SCPC/FM) or phase shift keying (PSK) and subsequentlyusing time division multiple access/phase shift keying (TDMA/PSK) in order to prot from theexibilityof digital techniques (see Chapter 4). Simultaneously, the progress of antenna technology(see Chapter 9) enabled the beams to conform to the coverage of the service area; in this way theperformance of the link was improved while reducing the interference between systems.Multibeam satellites emerged, with interconnection between beams achieved by transponderhopping or on-board switching using SSTDMA (satellite-switched time division multiple access).Scanning or hopping beams have been implemented in connection with on-board processing onsome experimental satellites, such as Advanced Communications Technology Satellite (ACTS).Multiple beamantennas of today may produce hundreds of beams. Indeed, this brings a twofoldadvantage: the link budget is improved to small user terminals thanks to the high satellite antennagainobtainedwithverynarrowbeams; andthe capacityis increasedbyreusingthe frequencybandallocated to the system many times.Flexible interconnectivity between beams is required more than ever and may be achieved atdifferent network layers by transparent or regenerative on-board processing. Regenerativepayloads take advantage of the availability of baseband signals thanks to carrier demodulation.This is discussed in Chapters 7 and 9. Intersatellite links were developed for civilian applicationsin the framework of multisatellite constellations, such as IRIDIUM for mobile applications, andeventually will develop for geostationary satellites (Chapters 5 and 7). The use of higherfrequencies (Ka band at 30/20 GHz) enables the emergence of broadband services, thanks to thelarge amount of bandwidthcurrentlyavailable, inspite of the propagationproblems causedbyraineffects (Chapter 5).1.7 SERVICESInitially designed as trunks which duplicate long-distance terrestrial links, satellite links haverapidly conquered specic markets. A satellite telecommunication system has three propertieswhich are not, or only to a lesser extent, found in terrestrial networks; these are:the possibility of broadcasting;a wide bandwidth;rapid set-up and ease of reconguration.The preceding section describes the state of technical development and shows the development ofthe ground segment in respect of a reduction in the size of stations and a decreasing station cost.Initially a satellite systemcontained a small number of earth stations (several stations per countryequipped with antennas of 15 to 30 m diameter collecting the trafc from an extensive areaby means of a ground network). Subsequently, the number of earth stations has increased withServices 15a reduction in size (antennas of 1 to 4 m) and a greater geographical dispersion. The stations havebecome closer to the user, possibly being transportable or mobile. The potential of the servicesoffered by satellite telecommunications has thus diversied.Trunking telephony and television programme exchange; this is a continuation of the originalservice. The trafc concerned is part of a countrys international trafc. It is collected anddistributed by the ground network on a scale appropriate to the country concerned. Examplesare INTELSAT and EUTELSAT (TDMA network); the earth stations are equipped with 15 to30 m diameter antennas.Multiservice systems; telephone and data for user groups who are geographically dispersed.Each group shares an earth station and accesses it through a ground network whose extent islimited to one district of a town or an indust