Understanding Cellular Radio (Artech House Telecommunications Library)

282 Pages·1998·0.71 MB·English

by  William Webb

Understanding Cellular Radio
Understanding Cellular Radio
William Webb
Artech House
Boston • London
LibraryofCongressCataloging-in-PublicationData
Webb,William,Dr.
Understandingcellularradio/WilliamWebb.
p. cm.—(ArtechHousemobilecommunicationslibrary)
Includesbibliographicalreferencesandindex.
ISBN0-89006-994-8 (alk.paper)
1.Cellularradio. I.Title. II.Series.
TK6570.M6W43 1998
621.3845’6—dc21 98-2921
CIP
BritishLibraryCataloguinginPublicationData
Webb,William
Understandingcellularradio—(ArtechHousemobilecommunicationslibrary)
1.Cellularradio
I.Title
621.3’8456
ISBN0-89006-994-8
CoverillustrationbyEliCedrone
©1998ARTECHHOUSE,INC.
685CantonStreet
Norwood,MA02062
Allrightsreserved.PrintedandboundintheUnitedStatesofAmerica.Nopartofthisbook
may be reproduced or utilized in any form or by any means, electronic or mechanical, in-
cludingphotocopying,recording,orbyanyinformationstorageandretrievalsystem,with-
outpermissioninwritingfromthepublisher.
Alltermsmentionedinthisbookthatareknowntobetrademarksorservicemarkshave
beenappropriatelycapitalized.ArtechHousecannotattesttotheaccuracyofthisinforma-
tion.Useofaterminthisbookshouldnotberegardedasaffectingthevalidityofanytrade-
markorservicemark.
InternationalStandardBookNumber:0-89006-994-8
LibraryofCongressCatalogCardNumber:98-2921
10987654321
Contents
Preface xi
Objectives xi
Acknowledgments xii
Part I Wireless Communications Systems 1
1 Introduction 3
1.1 Whyabooksimplyexplainingtechnicalaspects? 3
1.2 Scopeofmaterialcovered 4
1.3 Acronyms,abbreviations,andotherwaystomakeit
1.3 complicated 4
1.4 Howtoreadthisbook 5
1.5 Furtherreading 6
v
vi Understanding Cellular Radio
2 Overview of a Cellular System 7
2.1 Introduction 7
2.2 Whyitiscalledcellular? 7
2.3 Systemoverview 9
3 Basic Cellular System Design 21
3.1 Introduction 21
3.2 Thescarcityofradiospectrum 22
3.3 Theuseofcellsasameanstoconservespectrum 27
3.4 Whyonechannelcanservemanyusers 31
3.5 Basicnetworkdesignprinciples 35
3.6 Connectingupthenetwork 41
3.6.1 Leasedlink 42
3.6.2 Microwavelinks 43
3.6.3 Satellitelinks 46
Part II Getting Calls to Moving Subscribers 49
4 Keeping Track of Where the Users Are 51
4.1 Introduction 51
4.2 Theconceptoflocationareas 51
4.3 Attachanddetach 53
4.4 Periodiclocationupdating 54
4.5 Themobileinacall 55
5 How Calls are Made Between Two Users 57
5.1 Introduction 57
5.2 Paging 57
5.3 Respondingtoapagingmessage 59
6 Hand-off 69
6.1 Themobileinacall 69
6.2 Handingthemobiletoanothercell 69
Contents vii
6.3 Cellselectioninidlemode 71
7 Network Management, Roaming, and Authentication 73
7.1 Networkmanagement 73
7.1.1 Monitoringthecorrectworkingofthenetwork 74
7.1.2 Deliveringnetworkstatistics 74
7.1.3 Changingnetworkconfiguration 75
7.1.4 Addinganddeletingsubscribers 75
7.1.5 Generatingbills 76
7.1.6 Monitoringfraud 77
7.1.7 Providingcustomercare 77
7.2 Internationalroaming 78
7.3 Authenticationandciphering 79
7.4 Callrouting 82
Part III Transmitting the Signal 85
8 Radio Propagation 87
8.1 Introduction 87
8.1.1 Distance-relatedattenuation 89
8.1.2 Slowfading 91
8.1.3 Fastfading 91
8.2 Widebandchannels 94
8.3 Predictingcellularcoverage 95
8.4 Sectorization 96
8.5 Microcellsandunderlay/overlaynetworks 98
9 Radio Systems 101
9.1 Fromspeechtoradiowaves 101
9.2 Speechcoding 102
9.3 Errorcorrectioncodingandinterleaving 106
9.4 Interleaving 110
9.5 Modulation 111
viii Understanding Cellular Radio
9.6 Frequencyhopping 112
9.6.1 Overcomingfading 112
9.6.2 Reducinginterference 114
9.7 Equalization 116
9.8 Multipleaccess 118
9.8.1 FDMA 120
9.8.2 TDMA 121
9.8.3 CDMA 123
9.8.4 CDMApowercontrol 132
9.9 Packetandcircuitswitching 133
10 TDMA or CDMA 137
10.1 Introductiontothedebate 137
10.2 AmoregenerallookatCDMAversusTDMA 138
10.2.1 Divisionofthefrequencies 140
10.2.2 Distributingtheinterference 140
10.2.3 MakingTDMAinterferencemoreeven 141
10.3 Comparisonofadvantagesanddisadvantages 142
10.3.1 Capacity 142
10.3.2 Greaterrange 143
10.3.3 Sectorization 143
10.3.4 Nofrequencyplanning 145
10.3.5 Macrocell/microcell 145
10.3.6 Risk 147
10.3.7 Cost 147
10.3.8 Bandwidthflexibility 147
10.3.9 Frequencyhoppingversusdirectsequence 147
10.4 Summary 148
Part IV Specific Radio Systems 151
11 Cellular Systems 153
11.1 Thedifferencebetweenanaloganddigitalcellular 153
Contents ix
11.2 Cellularsystemsinoverview 155
11.3 GSM 160
11.3.1 Framingformat 160
11.3.2 Howmobilesmeasureadjacentcells 174
11.3.3 Numberingscheme 175
11.3.4 Spectrumefficiency 176
11.4 CDMAone 177
11.4.1 Softhand-off 181
12 Cordless Systems 183
12.1 Overviewofcordless 183
12.2 DECT 185
12.3 PHS 187
13 Overview of Wireless Local Loop Systems 191
13.1 Introduction 191
13.2 Accesstechnologies 194
13.3 TheattractionofWLLsystems 197
13.4 CurrentstatusofWLL 200
13.5 ThedifferencesbetweenWLLandcellular 201
13.6 WLLpropagation 201
13.6.1 Fastfading 203
13.6.2 Newobstructions 204
13.6.3 Rainfall 204
14 WLL Technologies 207
14.1 Introduction 207
14.2 TheLucentAirLoopWLLsystem 208
14.2.1 Localexchange(termedaswitchinGSM) 211
14.2.2 CATU(termedabasestationcontrollerinGSM) 211
14.2.3 CTRU(termedabasestationinGSM) 212
14.2.4 Thesubscriberunit(mobileinGSM) 212
14.3 DECTasaWLLtechnology 212
x Understanding Cellular Radio
15 The Future of WLL 217
15.1 Introduction 217
15.2 TechnicaladvancesinWLL 218
15.3 Technicaladvancesinotheraccesstechniques 219
15.4 Changinguserdemand 220
15.5 PredictionsforWLL 222
16 Satellite Systems 225
16.1 Whyusesatellites? 225
16.2 Howsatellitesystemswork 226
16.3 Willsatellitesystemsbesuccessful? 227
17 The Future of Cellular 231
17.1 Whatcouldbebetterthancurrentsystems? 231
17.2 Thethird-generationideal 232
17.2.1 GSMevolution 235
17.3 Mobile/fixedconvergence 237
17.4 Thelongertermfuture 238
Bibliography 241
Model Answers 247
Glossary 257
About The Author 271
Index 273