Of course, this book would not have been written if it was not thought that WLL will have a bright future. That view is shared by most industry experts, as is shown in the predictions in Figure 19.2 (reproduced from Chapter 5).
Recall also the prediction made by analysts that by the year 2000 over 10% of all lines being installed will be wireless. Other analysts have predicted that the number of wireless lines installed per year could overtake wired lines before the year 2005.
Such a prediction is not difficult to believe when the following factors are taken into consideration:
■ The cost per line for WLL currently is lower than for wired systems and will fall further with economies of scale.
The Future 299
■ The demand for telecommunications around the world will in- crease significantly in coming years.
■ Fragmentation and the development of market niches in the tele- communications market will allow a range of different operators to coexist.
The predictions do not hinge on any technical or commercial break- through, although they do require that other access technologies do not develop unexpectedly or that other access technologies are discovered.
Of course, there will be some problems. Some operators will fail in the first few years through a misunderstanding of the market or through the deployment of inappropriate equipment. Problems soon will emerge with lack of radio spectrum, and that, in effect, will increase the cost of radio spectrum, either directly through auctions or indirectly through the impossibility of obtaining more, forcing greater network costs as smaller cells are deployed. That will be partially solved as higher frequencies are used, but as with mobile radio, shortages of spectrum will remain a permanent problem, limiting subscriber numbers and the data rates that can be offered.
The future of WLL is bright. Hopefully, you are now persuaded to invest some of your time or money in it.
300 250 200 150 100 50 0
Installedlines (millions) Dataquest Strategis Group PA Ovum Herschel Shostek
Figure 19.2 Market predictions for WLL made at the start of 1997.
List of Acronyms
ADPCM adaptive differential pulse code modulation ADSL asymmetric digital subscriber line
AM amplitude modulation
AMPS Advanced Mobile Phone System ARQ automatic repeat request
BCH Bose-Chaudhuri-Hocquenghem
BER bit error rate
BRA basic rate access (ISDN at 144 Kbps) BSC base station controller
CAS channel associated signaling CATU central access and transcoding unit CDMA code division multiple access
301
CEPT European Conference of Postal and Telecommunications Administrations
CT-2 Cordless Telephony system 2 CTRU central transceiver unit D-AMPS digital AMPS
DAN DECT access node
DCA dynamic channel allocation
DCS1800 digital cellular system at 1800 MHz DECT digital enhanced cordless telephone DMT discrete multitone
DPSK differential phase shift keying
DS direct sequence
DSL digital subscriber line
ERMES European Radio Messaging System
ETSI European Telecommunications Standards Institute FAU fixed access unit
FDM frequency division multiplexing FDMA frequency division multiple access
FH frequency hopping
FTTC fiber to the curb FTTH fiber to the home FRA fixed radio access GAP generic access protocol GDP gross domestic product
GMSK Gaussian minimum shift keying
GSM global system for mobile communications HDSL high-speed digital subscriber line
HDTV high-definition TV HFC hybrid fiber coax IRR internal rate of return
ISDN Integrated Services Digital Network
ISI intersymbol interference
ISM industrial, scientific, and medical ITS intelligent telephone socket
ITU International Telecommunications Union LAN local area network
LMDS local multipoint distribution systems
LOS line-of-sight
MAN metropolitan area network
MMDS microwave multipoint distribution system MVDS microwave video distribution system NEXT near-end cross-talk
NIU network interface unit NMT Nordic Mobile Telephone NPV net present value
OFDM orthogonal frequency division multiplexing O&M operations and maintenance
PABX private access branch exchange PAMR public access mobile radio PCM pulse code modulation
PCS personal communications service PHS personal handiphone system
PM phase modulation
PMR private mobile radio
PN pseudo-random noise
POTS plain old telephony service
PSTN public switched telephone network
PTO Post and Telecommunication Organization QAM quadrature amplitude modulation
QPSK quadrature phase shift keying RBS radio base station
List of Acronyms 303
RF radio frequency RFA radio fixed access RLL radio in the local loop RNC radio node controller
RPE-LTP regular pulse excited-long term prediction RPI retail price index
RS Reed Solomon
SIR signal-to-interference ratio SMR specialized mobile radio SNR signal-to-noise ratio STRU subscriber transceiver unit
TACS total access communications system TCM trellis code modulation
TDD time division duplex
TDMA time division multiple access TETRA Trans-European Trunked Radio UHF ultra high frequency
USO universal service obligation
VDSL very high-speed digital subscriber line VSAT very small aperture terminal
VOD video on demand
WiLL Motorola’s version of wireless local loop WLL wireless local loop
xDSL belonging to the family ADSL, HDSL, and VDSL
About the Author
W graduated in electronic engineering with a first class honors degree and all top prizes in 1989. In 1992 he received his Ph.D. in mobile radio, and in 1997 he was awarded an M.B.A., all from Southampton University, United Kingdom.
From 1989 to 1993, Dr. Webb worked for Multiple Access Com- munications Ltd. as Technical Director in the field of hardware design, modulation techniques, computer simulation, and propagation model- ing. In 1993 he moved to Smith System Engineering Ltd., where he was involved in a wide range of tasks associated with mobile radio and spectrum management. In 1997 he joined Netcom Consultants, where he is a principal consultant in the Wireless Access division.
Dr. Webb has published more than 40 papers, holds four patents, was awarded the Institute of Electrical and Radio Engineers Premium in 1994, and is the co-author, with L. Hanzo, of Modern Quadrature Amplitude Modulation(New York: Wiley & Sons, 1992). He is a member of the IEE and a senior member of the IEEE.
305
Access technologies, 19–33 coax, 26–27
comparison of, 33 mobile radio, 30–31 summary of, 32–33
technical advances in, 295–97 TV broadcast, 29
twisted pair, 20–26 WLL, 31–32
Adaptive differential PCM (ADPCM), 92–94 bitstream, 93
defined, 92–93 use of, 93
Administrative pricing, 213–14 advantages/disadvantages of, 214 defined, 211
See alsoRadio spectrum AirLine, 182
AirLoop system, 281
Amplitude modulation (AM), 100 Analog cellular, 158–59
Applications license, 200–201 radio spectrum, 209
Asymmetric digital subscriber lines (ADSLs), 23, 24 Attenuation
distance-related, 72–73 rainfall and, 82 Base stations
controller costs, 239
controller interconnection costs, 239 controllers (BSCs), 160
costs, 238 DECT, 231 defined, 255 307
Base stations (continued) FDMA and, 105 GSM, 231
interconnection costs, 238–39 sectors, 290
site selection, 259 to switch links, 289–90 See alsoCell sites Billing, 273
Bit error rate (BER) channel, 76 Block coding, 97
Bose-Chaudhuri-Hocquenghem (BCH), 97
Broadband technologies, 181–82 Broadcasting, 13–15
access via, 29
advantages/disadvantages of, 29 digital TV, 14–15, 29
satellite TV, 13, 29 See alsoAccess technologies Business case, 233–51
financing arrangements, 245–47 network build costs, 235–40 on-going costs, 241–42 overall structure of, 233–35 predicting revenue, 243–45 summary financial statistics, 247–50 tariffing policies, 250–51
Buster, Claude, 55 Cable TV, 13–14 Calhoun, C., 56, 63 Capacity, 120–24
calculating, 140–41 comparison, 185–86
number of cells required for, 257 Case study, 275–92
GOS, 280–81
market demand forecast, 275–80 network building plan, 286 network configuration, 286–90 numbering requirements, 285–86 radio spectrum requirements, 281–85
sectorization, 283 summary, 291–92
traffic matrix and routing, 290–91 vendor selection, 281
Cells
4-sector arrangement, 261 connecting to switch, 263–71 defined, 255
hierarchical structure of, 263 number for capacity, 257 number of, 255, 257
omnidirectional arrangement, 261 sectorization of, 260–62
size calculation of, 284 Cell sites
defined, 255 negotiation, 260 planning, 260 selecting, 258–63
selecting number of, 255–58 See alsoBase stations Cellular technologies, 12–13,
30–31, 157–69 analog, 158–59 DCS1800, 160–61
deployment in WLL networks, 168 digital, 160–64
future, 164–67 GSM, 160–61 IS-95, 161–64 propagation, 71–72 at start of 1997, 139 strengths of, 157 summary of, 167–69 TACS, 158–59 WLL and, 158
See alsoWireless technologies Central access and transcoding unit
(CATU), 177 Central European Post and
Telecommunications (CEPT), 155, 204–5 radio spectrum plan, 205
308 Introduction to Wireless Local Loop
recommendations, 204
Central transceiver unit (CTU), 177 Centrex, 224
Channel-associated signaling (CAS), 270–71 Ciphering, 94–95 Circuit switching, 117–18 Coaxial cable, 13–14, 26–28
advantages/disadvantages of, 28 FTTH, 26
HFC, 26
tree-and-branch architecture, 26, 27 See alsoAccess technologies
Code division multiple access (CDMA), 8, 83, 107–11 advantages, 110
bandwidth flexibility, 128 capacity, 120–24
calculation, 120, 163 equation, 121 higher, 122–24 code choice, 108 codeword length, 108 cost, 128
defined, 102 diagram, 103 DS-CDMA, 128–29 FH-CDMA, 128–29, 173 frequency planning, 126 gain, 121, 123–24 interference and, 127 numerical representation of
waveforms, 112
operation in unlicensed bands, 126–27 orthogonal code, 117
power control and, 110–11 range, 125
risk, 127–28 sectorization, 125–26 signal generation example, 109 spreading codes in, 111–17 summary, 129–30 TDMA vs., 119–30
technologies, 174–78 WiLL, 168–69
WLL operator use of, 124 WLL systems, 108
WLL vs. mobile purposes, 115
Code excited linear predicator (CELP), 178 Competition
advantages of, 216
current environment of, 229, 232 deregulation and, 210
disadvantages of, 217 high, 49–50 limited, 46–48
radio spectrum, 212, 216–17 in trunk network, 46 Computing, 15–16
network, 15
PTO provision and, 17 Connections, 263–71
decision factors for, 263–64 leased link, 264
microwave link, 265–69 options for, 263 protocols for, 269–71 satellite link, 269 Convergence, 9–18
broadcasting and, 13–15 computing and, 15–16 environment of, 16–18 telecommunications and, 11–13 Convolutional coders, 97, 98 Cordless technologies, 31, 143–55
comparison of, 153 CT-2, 151–52 DECT, 145–50 original concept of, 143 PHS, 124, 150–51 at start of 1997, 139 summary of, 152–55 Costs, 60–66
access, 60 base station, 238
base station controller, 239
Costs (continued) base station controller
interconnection, 239
base station interconnection, 238–39 billing system, 239
calculation of, 140 CDMA, 128
comparison of, 186–88 division of, in network, 245 fixed-link, 266, 267 general management, 241 leased line, 241, 266, 267
maintenance, 62–63, 65–66, 239, 241 marketing/sales, 241
microwave link, 266 network, 238–39 network building, 235–40 on-going, 241–42 operation, 239 radio spectrum, 241 rental, 241 satellite link, 269 service offering, 221
subscriber equipment, 235–38 subscriber management, 241 switch, 239
TDMA, 128 through-life, 66 wired system, 61–63 wireless system, 63–66 See alsoEconomics Coverage
in-building, 229 planning tools, 86 predicting, 86–87 radio spectrum, 219 CT-2, 151–52
comparison with DECT and PHS, 153 defined, 151
equipment, 151 key parameters of, 152 See alsoCordless technologies Customer care, 273
Daisy-chaining, 290
Data, in service offering, 222–23 DECT access node (DAN), 148, 149 Deregulation, 210
Deutsche Telekom, 48 Developing countries, 39–42
India, 41–42
license opportunities in, 196–98 South American, 197
teledensity, 40, 197 telephony installation, 40 Diffraction, 77–79
angles, 79 defined, 77 loss variations, 78
for particular obstruction with frequency, 78
See alsoReflection Digital AMPS (D-AMPS), 134 Digital cellular, 160–64
Digital European cordless telephone (DECT), 31, 145–50, 182 advantages of, 145, 147
base stations/handsets, 231 capacity and, 48
comparison with PHS and CT-2, 153 cordless technologies of, 144 DAN, 148, 149
DCA, 146 delay, 154 Ericsson, 147–48 FAU, 148
key parameters of, 150 RNC, 148, 149 standard, 136–37, 145 TDD, 145–46
TDMA transmission, 145 transceiver requirement, 154 See alsoCordless technologies
Digital subscriber lines (xDSL), 16, 22–26 ADSL, 23, 24
advantages/disadvantages of, 25–26 approaches, 23
310 Introduction to Wireless Local Loop
defined, 22–23 HDSL, 23, 24
installation modification requirements, 25 technical advances in, 295 VDSL, 23, 24
See alsoTwisted pair Direct-sequence CDMA
(CD-CDMA), 128–29 Discrete multitone (DMT), 24 Distance-related attenuation, 72–73 DSC Airspan, 174–76
defined, 174–75
key parameters of, 175–76 radio channels, 175 Dual-mode phones, 231 Dynamic channel allocation
(DCA), 123, 124, 146, 151 Eastern Europe, 43–45
GDP for, 199 Hungary example, 43 information gathering, 198 license opportunities in, 198–200 mobile communication, 43–44 solutions, 44
teledensities, 43, 199 waiting lists for, 199 WLL networks in, 44–45 Economics, 59–68
access costs and, 60 components, 59–60 cost base and, 60 hybrid system, 67 market forecasts, 67–68 wired system, 61–63 wireless system, 63–66
Economic value analysis, 211, 212–13 advantages/disadvantages of, 213 application of, 212
defined, 211
See alsoRadio spectrum Efficient use of the spectrum, 207
Ericsson DECT system, 147–48 architecture illustration, 148 components, 148
Erlang formula, 258 Error correction, 96–99
block coding, 97 convolutional coding, 97 deployment, 96 redundancy, 96 system functioning, 99 European Telecommunications
Standardization Institute (ETSI), 134
spectrum mask, 137 standardization program, 136 WLL and, 136
Fading fast, 73–76 Rayleigh, 74–75 slow, 73
Fast fading, 73–76, 81 defined, 73–74 difficulties, 75 Rayleigh, 74–75 WLL and, 75–76 Fax, in service offering, 222 Fiber to the curb (FTTC), 24, 26 Fiber to the home (FTTH), 26 Financing arrangements, 245–47
direct funding, 246 self-funding, 246
shareholder funding, 246–47 vendor funding, 246 First world countries, 45–53
defined, 45–46 Germany, 48 high penetration, high
competition, 49–50 high penetration, limited
competition, 46–48 license opportunities in, 200 U.K. marketplace, 50–53
First world countries (continued) WLL advantages/disadvantages in, 50 Fixed access unit (FAU), 148
Fixed links costs, 266
leased-line costs vs., 267
Fixed radio access (FRA).SeeWireless local loop (WLL)
Frequencies (WLL), 83–85 need for, 84
proposed, 85 scarcity of, 83–84 standardization of, 84 used, 85
Frequency division duplex (FDD), 172 Frequency division multiple access
(FDMA), 102–5
advantages/disadvantages of, 105 base station and, 105
channels, 117 defined, 102 diagram, 103 ideal spectrum, 103
Frequency division multiplexing (FDM), 24 Frequency-hopped CDMA
(FH-CDMA), 128–29, 173 Frequency planning, 126
Fresnel effect, 80 Full mobility, 227–28 Future public land mobile
telecommunications system (FPLMTS), 164
Gaussian minimum shift keying (GMSK), 160
Generic access protocol (GAP), 145 Germany, 48, 54
Global systems for mobile communications (GSM), 30, 160–61
available services, 161 base stations/handsets, 231 BSCs, 160
comparison with TACS and IS-95, 167
defined, 160
dual-mode phones, 231 GMSK and, 160 key parameters of, 162 network components, 160 ramping up for burst, 106 spectrum, 104
speech coder, 161
See alsoCellular technologies Grade of service (GOS), 280–81
parameters, 280 targets, setting, 280 transmission network, 281 Gross domestic product (GDP), 38
for Eastern Europe, 199 figures for South America, 197 teledensity vs., 38
High-rate digital subscriber lines (HDSLs), 23, 24 Hungary, 43
Huygens-Fresnel theory, 80 Hybrid fiber coax (HFC), 26 Hybrid systems, 67
In-building coverage, 229 India, 41–42
Industrial, scientific, and medical (ISM), 126
Integrated Service Digital Network (ISDN), 16, 21–22 advantage of, 22
defined, 21–22 price of, lowering, 49 primary rate, 22 in service offering, 222
Intelligent telephone socket (ITS), 177, 178 Interleaving, 99–100
disadvantage of, 99 illustrated, 100
Internal rate of return (IRR), 249–50 calculation of, 250
defined, 249
312 Introduction to Wireless Local Loop
iterative approach to solving, 250 International service, 226–27
International Telecommunications Union (ITU), 11
Internet, 15
service provision, 226 telephony, 296
Intersymbol interference (ISI), 75, 83 symbol rate and, 83
TDMA and, 106 IS-95, 161–64
air interface specification, 162 comparison with TACS and GSM, 167 defined, 161–62
fax/data support, 163 key parameters of, 164 See alsoCellular technologies ITU, 203
radio division (ITU-R), 203, 204 recommendations, 203, 204 WLL and, 204
Leased links, 264 cost of, 241, 264, 266 fixed-link costs vs., 267 lines, 225–26
Licenses, 195–219
application for, 200–202 in developing countries, 196–98 in Eastern European countries, 198–200 in first world countries, 200
government objectives, 201–2 opportunities for, 195–200 radio spectrum issues and, 202–19 License spotters, 195–96
Limited mobility, 228–29 Line-of-sight (LOS), 73, 76 Line-of-sight (LOS) channel, 76–80
determining, 76 diffraction and, 77–79 prediction of, 86 reflection and, 79–80 time variation in, 81–82
Lines, provision of, 276–77 Long-distance service, 226–27 Lucent Airloop, 176–78, 182
CATU, 177 central office, 177 CTU, 177 defined, 176
key parameters for, 179 network architecture, 176 NIU, 177–78
See alsoProprietary technologies Macrocells, 127
Maintenance costs, 241 buried cable, 62–63 WLL, 65–66
Market demand forecast, 275–80 provision of lines, 276–77
service offering determination, 277–78 traffic routing, 278–80
Market forecasts, 67–68 difficulty of, 67 prediction chart, 68 for year 2000, 68 Marketing/sales costs, 241 Masks, 94–95
defined, 94–95 multiplication by, 95 See alsoCiphering Mercury, 50, 54 Microcells, 127
Microwave links, 265–69 cost of, 266–67 defined, 265
interconnection arrangements, 268–69 range variation, 265
See alsoNetwork rollout
Microwave multipoint distribution systems (MMDS), 180
Microwave video distribution systems (MVDS), 16, 179–81 advantages/disadvantages of, 32 defined, 32
Microwave video distribution systems (continued) economics of, 181 immaturity of, 180 key parameters of, 180–81 Mobile radio, 12–13, 30–31
cellular systems, 30 cordless systems, 31 private (PMR), 207–8 third-generation, 294 Mobility, 227–32
defined, 227–28 full, 227–28 limited, 228–29 no, 228 options, 230–31 provision of, 228 Modems
cable, 28 defined, 20 standards, 20 voiceband, 20–21 Modulation, 100–102
AM, 100 PCM, 92 PM, 100
QAM, 20, 27, 100 TCM, 100
Multipath propagation, 74 Multiple lines, 224–25
Near-end cross-talk (NEXT), 24 Net present value (NPV), 248–49 Network building costs, 235–40
base station, 238
base station connection, 238–39 base station controller, 239 base station controller
interconnection, 239 billing system, 239
combining elements of, 239–40 maintenance, 239
network, 238–39
operation, 239
spreadsheet example for, 240 subscriber equipment, 235–38 switch, 239
Network configuration, 286–90 base station to switch links, 289–90 illustrated, 288
interswitch links, 288–89 interswitch signaling system, 289 interswitch synchronization, 289 See alsoCase study
Network interface unit (NIU), 177–78 ITS, 177, 178
STRU, 177, 178 Network rollout, 253–74
billing and, 273 block diagram, 254 connections, 263–71 customer care and, 273
subscriber unit installation, 272–73 summary, 273–74
Networks
building plan for, 286
plan deployment illustration, 287 schematic, 255
Nordic Mobile Telephone (NMT), 54, 169 Nortel Proximity I, 172–73
defined, 172 key parameters, 173
Numbering requirements, 285–86 Nyquist theorem, 92
Oftel, 52
On-going costs, 241–42 spreadsheet example, 242 types of, 241
Operations-and-maintenance (O&M), 150 Operator services, 224 Organization, this book, 7–8 Orthogonal frequency division
multiplexing (OFDM), 24
314 Introduction to Wireless Local Loop
Packet switching, 117–18 connection-oriented, 117 nonconnection-oriented, 117 uses, 118
Personal computers (PCs), 10 Personal handiphone system
(PHS), 124, 150–51
comparison with DECT and CT-2, 153 DCA, 151
defined, 150 delay, 154
key parameters of, 151 TDMA-TDD approach, 150 See alsoCordless technologies Phase modulation (PM), 100 Phoenix system, 178–79 Plain old telephony (POTS), 222
Post and telecommunications organizations (PTOs), 12
computer access and, 17
first world country, 46–47, 49–50 monopolies and, 57
Priority and preemption, 226 Private access branch exchange
(PABX), 144
Private mobile radio (PMR), 207–8 Proprietary technologies, 171–84
broadband, 181–82 CDMA, 174–78 characteristics of, 171 comparison of, 183 defined, 171
DSC Airspan, 174–76 equipment sales, 184 growth of, 172 Lucent Airloop, 176–78 MVDS, 179–81
Nortel Proximity I, 172–73 Phoenix, 178–79
at start of 1997, 139 summary of, 182–84 Tadiran Multigain, 173–74 TDMA, 172–74
See alsoWireless technologies Protocols, interconnection, 269–71 Pseudo-noise (PN) codes, 115
advantages of, 116 defined, 116 multiplying, 116
Public switched telephone network (PSTN), 11
Pulse code modulation (PCM)
adaptive differential (ADPCM), 92–94 defined, 92
inefficiency, 92 Q.931, 270–71
Quadrature amplitude modulation (QAM), 20, 27, 100
Quadrature phase shift keying (QPSK), 172 Radio fixed access (RFA).SeeWireless
local loop (WLL)
Radio in the local loop (RLL).SeeWireless local loop (WLL)
Radio node controller (RNC), 148, 149 Radio planning, 260
Radio propagation, 71–87 cellular, 71–72
distance-related attenuation, 72–73 environment of, 71–76
fast fading, 73–76 multipath, 74 phenomena, 72 slow fading, 73 Radio spectrum
administrative pricing, 211, 213–14 allocation/assignment methods, 211–17 applications, increase in, 209
CEPT plan, 205 channel plan, 282
competitions, 212, 216–17 congestion, 206
costs, 241
coverage obligations, 219 deregulation and, 210
Radio spectrum (continued)
economic value analysis, 211, 212–13 efficiency, 207–8, 281–82
as government revenue-raising resource, 211
growth in demand, 209 issues, 202–19 management, 202–11 management and WLL, 217 management technique
implications, 217–19 manager privatization, 211 manager tasks, 205–6 openness and, 210 pricing, 217 profits, 210
requirements, 281–85 shortage implications, 218 trading, 211–12, 214–16 trends, 208–9
Radio systems, 89–118 block diagram, 90 ciphering, 94–95
error-correcting coding, 96–99 interleaving, 99–100
modulation, 100–102 multiple access, 102–11
packet/circuit switching, 117–18 speech encoding, 89–94
Rainfall, 81–82 Range, 125 RAS, 168
Rayleigh fading, 74–75 Redundancy, 96 Reed-Solomon (RS), 98 Reflection, 79–80
defined, 79 materials and, 79 WLL and, 79–80 See alsoDiffraction
Regular pulse excited - long term prediction (RPE-LTP), 93 Revenue prediction, 243–45
revenue division and, 245 spreadsheet example for, 244 Satellite links, 269
Satellite TV, 13
Sectorization, 125–26, 260–62, 283 Self-funding, 246
Service offerings, 221–32
case study determination of, 277–78 Centrex, 224
choosing, 221–32 components of, 222–27 cost and, 221
data, 222–23 fax, 222
Internet service, 226 ISDN, 222
leased lines, 225–26 long-distance/international
services, 226–27 mobility and, 227–32 multiple lines, 224–25 operator services, 224 POTS, 222
supplementary services, 223–24 videophone, 223
Shareholder funding, 246–47 Signaling system 7 (SS7), 270
Signal-to-noise ratio (SNR), 20, 28, 121 Slow fading, 73
South American, 197 Speech coding, 89–94
coders, 94 defined, 89–90 WLL and, 93–94 Speech waveforms, 91–92
changing, 93 illustrated, 91 Spreading codes, 111–17
defined, 112 sequence, 112 Walsh, 115
316 Introduction to Wireless Local Loop
See alsoCode division multiple access (CDMA)
Standards, 134, 135–38 ETSI, 136, 137 lack of, 136–37
Subscriber equipment costs, 235–38 calculation spreadsheet, 237 subsidization of, 236
Subscriber management costs, 241 Subscriber units
future cost of, 295 installing, 272–73
transceiver (STRU), 177, 178 Subsidization, 57–58
subscriber unit, 236 unsustainability of, 58
Summary financial statistics, 247–50 IRR, 249–50
NPV, 248–49
spreadsheet example, 247 Switch
base station to, links, 289–90 costs, 239
interswitch links, 288–89 interswitch signaling system, 289 interswitch synchronization, 289 Tadiran Multigain, 173–74
defined, 173
key parameters of, 174 voice coder, 174
See alsoProprietary technologies Tariffing policies, 250–51 Technical advances, 294–97
in Internet telephony, 296 in WLL, 294–95
in xDSL technologies, 295 Telecommunications, 11–13
in developing countries, 39–42 in Eastern Europe, 43–45 environment, 37–58
in first world countries, 45–53
Telephony
in developing countries, 40 Internet, 296
plain old (POTS), 222 provision of, 16
Time division duplex (TDD), 145–46 advantages of, 145
capacity comparison, 146 defined, 145
Time division multiple access (TDMA), 8, 105–7 advantages/disadvantages of, 107 bandwidth flexibility, 128 burst structure, 106 capacity, 120 CDMA vs., 119–30 channel timeslot, 117 cost, 128
defined, 102 diagram, 103 gain, 125 inefficiencies, 105 ISI and, 106
operation in unlicensed bands, 126–27 overhead, 106
range, 125 risk, 127–28 sectorization, 125–26 sectorization gains, 262 spectrum efficiency, 107 technologies, 172–74
Total access communications system (TACS), 158–59
comparison with GSM and IS-95, 167 defined, 158
disadvantages of, 159 key parameters of, 159 See alsoCellular technologies Trading, 211–12, 214–16
advantages/disadvantages of, 215–16 defined, 211–12
options, 215 transitional steps, 215
Traffic
channels, number of, 258, 284 distribution, 278
matrix, 290–91 routing, 278–80
Tree-and-branch architecture, 26, 27 Trellis code modulation (TCM), 100 Twisted pair, 11, 20–26
emergence of, 12 ISDN, 21–22
technology summary, 26 voiceband modems, 20–21 xDSL technologies, 22–26 See alsoAccess technologies United Kingdom, 49, 50–53
BT market share, 52 liberalization history, 50–51 market share predictions, 53 Oftel, 52
USO, 51
WLL operator effect in, 51–52 WLL operator licensing, 51
U.S. Rural Electrification Administration (REA), 55
Universal Mobile Telecommunications System (UMTS)
defined, 164 features, 165
system characteristics, 166
Universal service obligation (USO), 51, 66 User demand, 297–99
V5.1, 270–71 V5.2, 270, 271 Vendors
funding from, 246 selection of, 281
Very high rate digital subscriber lines (VDSLs), 23, 24
Very small aperture terminals (VSATs), 269 Video on demand (VOD), 12
Videophone, in service offering, 223 Viterbi decoder, 98–99
Voiceband modems, 20–21 advantages/disadvantages of, 21 defined, 20
standards, 20 summary of, 21
Walsh code family, 115, 116 Wideband channels, 82–83 WiLL, 7, 168
Wired system costs, 61–63 maintenance, 62 types of, 61 variables in, 61–62
WLL vs., in high-density case, 64 WLL vs., in medium/low-density
cases, 65 Wireless local loop (WLL)
access via, 31–32 advantages of, 4, 31 coverage prediction, 86 defined, 3, 6–7
developments from 1950 to 1990, 55–56 disadvantages of, 32 as fixed-loop telephony
replacement, 229 frequencies for, 83–85 future of, 299–300 growth of, 55 history of, 53–57 information on, 5–6 market predictions for, 300 network launches, 35 operator competition, 17 role of, 3–4
technical advances in, 294–95 telephone-based, 31–32 video-based, 32
See alsoAccess technologies Wireless system costs, 63–66
cable vs., in high-density case, 64
318 Introduction to Wireless Local Loop