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ix

xi

xvii

1 1 2 2 6 9

21 26 26 27

8 30 30 30 35 40 41

43 43 43 44 49 49 50 52 52 56 61 63 65 65 66 7

on tents

2.3.5 Other Systems

2.4.1 ~enera l Charucteristics 2.4.2 I R ~ D I U ~ T M 2.4.3 ~ ~ O ~ A L S T A R TM

2.4.4 N E ~ I C O r ~ 2.4.5 C O ~ S T E ~ ~ T I O N C O ~ ~ U N I C A T I O ~ S r M 2.4.6 E ~ I P S O TM

2.4 Sate11ite-~ersonal C o ~ ~ u n i c a t i o n Networks (S-PCN)

References

eters

3. I . 1 ~istorical Context 3.1.2 E ~ ~ u t i o n of Sutellite Orbit - Proo~of ~ep le r ' s First b w 3.1.3 S a ~ e l ~ ~ t e Swept Area per Unit Time - Proof of ~ e p l e r ~ s Second Law 3.1.4 The Orbital Period - Proof of ~ep1er'~s Third Luw 3.1.5 sat ell it^ ~ e l o c i ~

3.2, 1 O ~ e ~ i e w .2 Satellite ~ u r u ~ e t e r s .3 Sutellite Location in the Orbitul Plane .4 Sutellite s cation with Respect to the Rotating ~ a r t h

3.2.5 Sutellite Location with Respect to the Celestial Sphere 3.2,Ci Satellite cation with Respect to Satell~te-Cent~ed Spherical Co"ordinutes 3.2.7 Sutell~te cuti ion with Respect to the Look Angles 3.2.8 ~ e o s t u t i o n a ~ Sutellite ~ c u t i ~ n

3.3. f ~enera l D~sc~ssion 3.3.2 ~ ~ e c t s of the ~ o o n and the S ~ n 3.3.3 of the Oblute Eurth 3.3.4 heric Drug

3.3 Orbital Pe~~rba t ion

tellation Design Desig~ ons side rations Polur Orbit Constelluti~n Inclined Orbit ~onste~lation

Channel Ch~ac te~s t i c s

~ r o w ~ u n ~ Channel ~ o d e l s 4.2.3 ~ i d e b a ~ d ~hunnel ~ o d e l s

4.3 ~ e r o n a ~ t i c ~ l Link

4.5 Fixed Link 4.5.1 ~ro~ospheric E ~ e c ~ s 4.5.2 1onos~heric ~ ~ e c t s

References

68 68 49 69 70 71 74 77 77 81

83 83 83 84 86 87 88 89 89 90 91 93 94 95 97

100 101 101 101 103 304 104 104 106 111 114

115 115 115 115 118 127 128 129 129 129 142 143

5.1 ~ntroduction 147 147 148

vii ont tents

5.3

5.4

5.5

5.2.1 P u ~ o s e 5.2.2 Trans~iss~on and ~ e c e ~ t i o n 5.2.3 ~ o i s e 5.2.4 Sate~lite Truns~ond~r

dulation I O9e~ iew

5.3.2 Phase Ship Keying 5.3.3 ~ i n i ~ u ~ S h ~ t ~ e ~ i n g 5.3.4 ~uudruture ~ ~ ~ l i t u ~ e ~odulation ~~A~~ Channel Coding 5.4.1 ~ a c k g r o u n ~ 5.4.2 Block Codes 5.4.3 Con9olutional Codes 5.4.4 Int~rleavin~ 5.4.5 Concutenated Codes 5.4.6 ~ u r b o Codes

7 A u t o ~ t i c ~ e ~ e a t ~ e ~ u e s t S c h e ~ e s ltiple Access

5.5.1 P u ~ o s e 5.5.2 ~~~~

5.5.3 T ~ ~ A 5.5.4 C ~ ~ A 5.5.5 Content~on Access S c h e ~ e s 5.5.6 S- U ~ ~ S ~ I ~ T - 2 0 0 Can~~date Solutions

eferences

6.1 In~oduction

6.2. I Ove~ iew of ~S~ Sig~alling ~rotocol Architectur~ 2 S-PCN Inte~aces and Signal~ing Protocol Architecture

. I Sutell~te Cells and Sutellite cation Areas 6.3.2 ~ c a t i o ~ ~ a n a g e ~ e n t

6.4. I ~b~ect ives 6.4.2 ~ ~ e c ~ s of Sutellite S y , s t e ~ Cha~acterist;cs 6.4.3 ~ ~ e c t s of ~ob i l i t y

.4 ~esource Allocation Strategies

.5 ~ e ~ o r k er at ions and P~ocedures eferences

7.1 In~oduction 7.2 Inte~ration with PSTN

7.2.1 Intro~~ction 7.2.2 ~ a t ~ w u y ~ u n c t i ~ ~ ~ and O~erat~ons 7.2.3 ~ ~ a t o c ~ l ~rchitecture of SSN7

7-3.1 Intrad~ction 7.3.2 I n t ~ ~ r u ~ ~ o n ~ e q ~ i ~ e ~ e ~ t s 7.3.3 ~ ~ t e g r a t i o ~ S~en~r io~s

148 148 152 158 163 163 163 168 168 168 168 169 174 180 181 181 182 184 184 186 186 188 193 194 195

197 197 3 98 198 199 20 1 20 1 202 20

224 224 225 226 227 23 1 243

247 247 248 248 248 49

253 54 54

256 258

I ~ ~ a c t of Inte~rat~on scenario^ on the an dove I ~ ~ a c t of lnte~rution Sc@~arios on the ~ c a t ~ o n I ~ ~ u c t of Integr~tion Scenurios on the Call Set- The Role of ~ ~ ~ 1 ” ~ o ~ e ~ e r ~ i n a l in T e ~ r e s t r i a ~ S - ~ ~ ~ Integratio~

~ o n c e ~ t of I n t e ~ o r ~ i n g Units *

The R ~ d i o - ~ e p e n ~ e n t and R a d i o - I n ~ e ~ e n ~ e ~ t ~ o n c e p ~

Satell~te Integration with ~ S ~ / E ~ ~ ~ - a Concl~s~on

~ r o c e d ~ r e

7.4 ration with Third ~ e ~ e r a t i o n (3C) Networks

ferences

26 1

290 29 1 291

93 93 95

297

297

299 30 1

309

319 319 320 323 324 325 32 33 330 33 1

339

34 1

53

359

wth in demand, sp

er the last 10 years, the s i ~ ~ i ~ ~ a n t market ~ e n ~ t r ~ t i o ~

sat~1lite ~ y s t ~ ~ s , namely the influence of t e ~ e s ~ i a l

this with v ~ i c ~ c o ~ ~ u n i c a

eface

offers a hostile environment in which to design a reliable communications link. reviews the present status of understanding with regard to the chara~terisation of the channel,

the methods of prediction. he characte~stics of the radio interface are considered in Chapter 5.

sion chain is analysed presenting the link budget method of analysis. The chapter includes a d~scription of applicable modulation and coding techni~ues and multiple access schemes.

In Chapter 6, the network ~rocedures associated with a mobile-satellite networ~ are presented. In order to facilitate a smooth inte~ration with terrestrial mobile netw impo~ant that as many of the procedures between the two systems are as similar as

r focuses on two key areas of mobility ~ a ~ a g e m e ~ t , namely location management er m~agement , as well as resource management techni~ues. In Chapter 7, the

re~u~ements for integration with fixed and mobile networks are presented, hi~hli~hting the re~uirements for integration with the GSM network.

Chapter 8 presents an analysis of the market potential for mobile-satellite co~unica t ions . The methodology for deriving the market is presented, followed by a series of rnaket predictions. Finally, in Chapter 9, we attempt to predict how the mobile-satellite market will develop over the coming decade.

C e ~ ~ n l y , it has been an interesting time to produce a book of this type. The next 10 years promise to be as innovative, if not more so, than the last, with the introduction of mobile multimedia s e ~ i ~ e s and a greater in~uence of the I n t e ~ e t on mobile service evolution. It will be interesting to see how the mobile-satellite communicatio~s industry adapts to meet these new markets over the next few years.

The texts extracted from the ITU material have been reproduced with the prior autho~sation of the union as copyright holder.

The sole responsibility for selecting extracts for reproduction lies with the b e n e ~ c i ~ e s of this autho~sation alone and can in no way be attributed to the ITU.

The complete volumes of the TTU material, from which the texts reproduc~d can be obtained from:

International Teleco~munication Union

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orbi t a1 characteristics

cal co-or~inate~

4 6

11 12 13 16 19 20 23 27 28 30 34 35 37 39 39 40

55

73 76 77 7

87 90 91 94 95 96 99

105 106 107 108

iv Figures

Figure 3.13 Figure 3.14 Figure 3.15 Figure 4.1 Figure 4.2 Figure 4.3 Figure 4.4 Figure 4.5 Figure 4.6 Figure 4.7 Figure Figure 4.9

Figure 5.2 Figure 5.3

Figure 5.6 Figure 5.7 Figure 5.8 Figure 5.9 Figure 5.10 Figure 5.1 1 Figure 5.12 Figure 5.13 Figure 5.14 Figure 5.15 Figure 5.1 6 Figure 5.1 Figure 5.1 Figure 5.1 Figure 5.20 Figure 5.2 1 Figure 5.22

Figure 5.25

Single geometry for single satellite coverage above latitude d> ~ e o m e ~ y for inclined orbit constellation optimisation Triangle triad used by Ballard for optimisation of the arc range y, Mobile network propagation environment ~ading at 1.5 GHz due to roadside shadowing versus path elevation angle Two-state Markov process indicating shadowed and un-shadowed operation Specific attenuation due to atmosphe~c gasses Total dry air and water vapour attenuation at the zenith from sea level Relationship between slant path length and rain height Rain intensity ( m ~ ) exceeded for 0.01% of an average year ~redicted (Watson-Hu ~ ~ d e 1 ) and ~easured attenuation at Lario station (Italy) Generalised elliptical waveform also illustrating: (a) vertical polarisation, (b) horizontal polarisation, (c) left hand circular pol~sation, (d) right hand circular pol~sation. The direction of travel is into the paper Faraday rotation as a function of TEC and frequency Simpli~ed transmission chain Antenna gain characteristics

GHz band atio ion in antenna gain with frequency Free space loss of: LEO (1000 km); ME0 (10000 km); and GEO Typical receiver chain 3~ghtness te~perature variation with frequency for extra terrestrial noise sources Noise figure variation Composite transmission chain Simple transparent ~ansponder

eference radiation pattern for vehicle mounted antennas operating in the 1-3

llite TWTA operational characteristics i-carrier payload configuration

payload employing microwave switching Comp~son of (a) ASK; (b) FSK; and (c) PSK QPSK modulation PSK phasor diagrams: (a) BPSK; (b) QPSK; (c) 8-PSK PSK de~odulator D-PSK demodu1ator Relationship between P, and E&'?() Signal space diagrams: (a) MSK; (b) 16-QAM RS code structure

a1f"rate convolutional encoder of constraint length 3 tate diagram representation

Tree diagram representation representation

Figure 5.26 trellis diagram Figure 5.27 nterleaver application Figure 5.28 Interleaver block Figure 5.29 code encoder/decoder Figure 5.30 schemes: (a) stop-and-wait; (b) continuous ARQ with repeat;

(c) continuous ARQ with selective repeat usage of shared transponder bandwid~ MA application

Figure 5.33 Typical TDMA frame structure Figure 5.34 F D ~ A ~ D M A hybrid access scheme Figure 5.35 PN sequence auto-correlation function R(T) Figure 5.36 Direct sequence CDMA Figure 5.37 DS-CDMA interference rejection capability Figure 5.38 Frequency hopped CDMA

110 112 113 116 120 126 130 132 133 134 138

140 142 147 149

150 15 1 152 153 154 156 158 158 3 59 160 161 163 164 164 165 166 167 168 173 173 175 177 178 178 179 180 182

184 185 3 85 187 187 189 189 191 192

Figures xv

Figure 5.39 Comp~son oT: (a) direct sequence and (b) frequency hopping CDMA techniques 192 Figure 6.1 GSM signalling protocols and dis~bution among network elements 198

Figure 6.3 ~ocation manage~ent operations 203

Figure 6.5 Partial GCA 205 Figure 6.6 Location area for terminal position approach 207

Figure 6.8 Database p~itioning 213 Figure 6.9 Database hierarchy 213 Figure 6.10 Intra-satellite inter-s~t-beam handover 216 Figure 6.1 1 Inter-satellite handover 216 Figure 6.12 Inter-FES handover 217

6.13 Terrestrial to satellite handover 218 6.14 Satellite to terrestrial handover 219 6.15 Hard handover 222

Figure 6.16 Switched diversity handover 223 Figure 6.17 Combined diversity handover 223 Figure 6.18 Signalling diversity 224 Figure 6.19 Satellite spot-beam cellular concept 228 Figure 6.20 DCA concept in cellular systems 230

gure 6.21 First user registration info~at ion flow [CEC-951 238 Figure 6.22 Subsequent user-registration info~at ion flow [CEC-951 239 Figure 6.23 Call set-up - outgoing call information flow 240 Figure 6.24 Call set-up - incoming call info~at ion flow 24 1 Figure 6.25 Mobile terminal initiated call release information flow 242 Figure 6.26 Network initiated cdl release information flow 243

Figure 6.2 Functional interfaces of a GMR system 200

Figure 6.4 Location area under guaranteed coverage area based approach

Figure 6.7 A fully ~ i s t~bu ted database architecture 212

20

Figure 7.1 Figure 7.2 Figure 7.3 Figure 7.4 Figure 7.5 Figure 7.6 Figure 7.7 Figure 7.8 Figure 7.9

S-P~N-PSTN si~nalling connection S-PCN-~STN gateway function SSN7 sign~ling architecture Routing label of SSN7 S - P C ~ - P S T ~ access function S-PCN-GSM integratio~ scenarios Integration at the Abis interface - common BSC Inte~ration at the A interface - common MSC

248 249 250 25 1 253 258 259 259

Integration at the E interface - separate MSC 260 Figure 7.10 Integration at the U, interface 26 1 Figure 7.1 1 Si~nalling flow for a GSM cell to a satellite spot-beam handover for integration

at the E-interface [CEC-951 263 Figure 7.12 GSM Inter-BSS handover protocol 270 Figure 7.13 GSM-to-satellite handover for integration at the A-interface - scenario 1 [CEC-95] 271 Figure 7.14 GSM-to-satellite handover for integration at the A-interface - scenario 2 [CEC-95] 272 Figure 7.15 Satellite to GSM handover - scenario 1 [CEC-95] 274 Figure 7.16 Satellite to GSM handover - scenario 2 [CEC-951 275 Figure 7.17 GSM location updating signalling flow [CEC-951 277 Figure 7.18 S-PCN location update for GCA based approach [CEC-951 278 Figure 7.19 S-PCN location update for TP based approach [CEC-95] 279

28 I Figure 7.21 Mapping of IMUIs and TMTIs onto different network segments for a group D Figure 7.22 map pin^ of the same IMUI onto different "ITIS with different network seg~ents

through two different DMTs 286 Figure 7.23 Re~registration mechanism for changing service association - scenario I 286 Figure 7.24 Re-registration mechanism for changing service association - scenario 2 28 Figure 7.25 Initial ~ M T S mobile equipment domain and core networks concept [ETS-981 28 Figure 7.26 Radio-~ependent and ~ddio-independent concept 288

ure 7.20 Call set-up procedure [CEC-951

vi ieures

in. EU-15 states

spheric platfom s c e ~ ~ o

9 0 1 4 5 6

304 30 305 308 309 31 1 312 312 313 313 3 14 314 315

334

ational consi~eratio~s Table 2.4b ~ o ~ ~ ~ i s o n of satellite orbits: i ~ ~ l e ~ e n t a t i o n considerations Table 2.5 sat satellite con~guration Table 2.6 Table 2.7

able 2.8

frequency alloc~tions below 500 MHz of mobile~satellite service f re~~encies in the L-/~-bands

c ~ ~ a c t e ~ s t i c s : satellite and orbit ch~ac te~s t ics : services ch~acteristics: radio interface

ue of M , for Julian dates calcula~on Value of the a z i ~ u t ~ angle 5 with respect to the relative position of the sub-satellite point

elevation [ITU-99a] ents for e s t i m a t i ~ ~ attenuation

oss ~otential market for di~erent terminal classi~cations rrestrial roll-out criteria

10 13 22 23 29 49 50 51 53 54 57 65 69 78 79 80 94

99 10 109 113 1 1 1 1 1 170 201

22 1 255 264

273 300 302 03

307

viii Tables

minutes per terminal type

ffs at service introduction Table 9.1 A~location of m~bile-sa~ellite service frequencies in the ~ a - b ~ ~ s

307 310 310 326

The mobile phone has proved to be one of the most outstanding technological and c o m ~ e r - cial successes of the last decade. Since its introd~ction in the 1980s, the phone’s place in the market place has rapidly progressed from a mino~ty, specialised item to virtually an essential c o ~ ~ o d i t y for both ~usiness and leisure use. Over the last two decades, advances in mobile te~hnology, combined with the significant reduction in operating c ts and the development of new applications and services, have ensured a buoyant market. mid-2000, there were over 220 million mobile subscribers in Europe and over 580 million mobile s~bscribers world-wide. In the UK, every other person owns a mobile phone; while in Finland the number of mobile phones per capita now exceeds that of households with fixed phone lines.

As with most technological innovations, the mobile phone’s marketability is not based on overnig~t success but rather a systematic, evolutionary development involving multi-national co-operation at both technical and political levels. In fact? the concept of a mobile phone is not new. As early as 1947, the cellular concept was discussed within Bell ~ a b o r a t o ~ e s [YOU- 791. , it was not until the 1970s that technology had developed su~ciently to allow the a1 i~plementation of such a system to be investigated.

The evolution of mobile communicatio~s can be categorised into generations of sently, we are on the verge of the third-~eneration ( 3 6 ) of mobile systems. first-generation (1G) systems are those that paved the way and are g

ational networks that are based on analogue technology, Such networks service in the 1980s. These networks were designed to provide voice

econd-generation (26) systems are categorised by digital technology. They are suppo~ed by i n t e ~ a ~ o n a l roaming agreements, allowing the possibility to operate a mobile phone across national boundaries. With the introduction of 2 6 systems, in addition to digital voice tele- phony, a new range of low data rate digital services became available, ~ncluding mobile fax, voice mail and short ~ e s s a g e service ) [PEE-001. Also at this stage in the evolution, new types of systems began to emerge w d for p ~ i c u l a r market needs; not only cell mobile, but also cordless, public mobile radio, satellite and wireless-local area n e t w o ~ ~ LAN) sol~tions. 2 6 systems are synonymous with the globalisation of mobile ~ystems, and in

obile Satellite ~ o r n ~ u ~ i ~ a t i o n ~ e t ~ o ~ ~ s

oduce mobile~multimedia services.

) based technologies is now the major d ~ v i n ~ force The 3 6 mobile co~mu~icat ions s

ations at data rates of up to and be s under the overall res~onsibility o

rink of the establishme~t of the mobile i n f o ~ a t i o ~ society.

divi~ing the service area i rces or cha~nels, whi access

~ o b i l e ~ o ~ ~ ~ ~ i c a t i o n System Evolution

~sua l ly cellular coverage is represented by a hexagonal cell structure to demonstrate the the shape of cells is d e t e ~ i n e ~ by the local to

used extensively by terrestrial cellular operator cellular networks. of a cell is d e t e ~ i n e d by its base st

com~u~ica te s with mobile users through si ansmitted in the direction from the and conversely9 the ~ ~ v e ~ ~ e Z ~ n ~ or

to the mobile are termed t h e ~ u ~ ~ ~ ~ nk is in the direction of mobile to

perform administrative and ~ a n a g e ~ e n t functions suc re used to convey the in fo~a t ion content of a call. is therefore divided between These are allocated for both fo

In order to increase the capacity of a network, there are three possibilities, either:

ater n u ~ b e r of channels are made available; spectr~lly efficient modulation and multiple access techni~ues

e c ~ a ~ n e l s are re-used, separated by a distance which wou acce~ ta~ le level of co-chan~el interference.

, which are limited in terms of available bandwidth, operat y re-use. This implies that the same pool of fre~uencies is re-

that are su~ciently separated so as not to cause h m f u l co-channel interfe hexa~onal cell s ~ c ~ r e , it is possible to cluster cells so that no two adjacent cells are

quency. This is only achievable for certain cell-cluster size om the relationship

N = i2 i- ij -i- j 2 (1.1) where i, j = 0, 1, 2, 3 , etc.

to the network is divided between cells in

the system cap~city can be increased, since more channels can be available

A seven-cell ~re~uency re-use ~ a t t e r ~ is shown in Figure 1.1. The total ban

ber of calls that can be suppo~ed in each cell.

ction in the cluster size will also res the s y s t e ~ may become more pron

e~uation

i s the mean re-use distance, R is the cell radius rrestrial mobile radio e~vironment, the strength

the transmitter i s related by the following expression:

(1.3)

w h e ~ ~ y is a constant related to the terrain environment, usually a s s u ~ e

Mobile Satellite Co~~un ica t ion Networks

e-Use

ure 1.1 Seven-cell frequency re-use pattern.

For a seven-cell re-use con~guration, the ratio of the ca~ier-to-inte~erence e ~ p e ~ e n c e d by a mobile from the six cells located at a ~ n i m u m re-use distance of D from the mobile, that is on the first tier of the cell cluster re-use pattern, is given by

From the above, q, termed the c o - c ~ a n ~ e l in te~e~ence r ~ ~ ~ ~ t i o ~ factor, is 891

Note: the above assumes that equal power is radiated by all cells and that the in t~~erence received from cells operating using the same frequency in the second tier of the cell cluster, can be neglected. Thus, for y = 4, a seven-cell cluster pattern can provide a C/I ratio of 18 In order to minimise the effect of co-channel inte~erence, power control techniques are employed at the mobile terminal and the that power levels are maintained at the ~ n i m u m level needed to ~a in ta in

ow the mobile user gains access to the available channels within a cell is g o v e ~ e d by the multiple access technique used by the network. Analogue cellular networks employ frequency division multiple access ( ~ M ~ ) , whereas digital networks employ either time division m~ltiple access ~TDMA) or code division multiple access (C seven cell re-use pattern is generally employed, whereas for CDMA a single-cell frequency re-use p a t t e ~ is achievable. Further discussions on the advantages and dra~backs of each technique, in the context of satellite communications, can be found in Cha~ter 5.

In a te~estrial mobile env i ro~en t , reception cannot rely on li~e-of-sight ly ~ependent upon the reception of signal r e~e~ t ions from the su te: This is the opposite of the mobile-satellite case, which is reliant on line-of- n, and is discussed in detail in Chapter 4.) The resultant scatte~ng and multip

components arrive at the receiver with random phase. The propa~ation channel can charac te~se~ by a combination of a slow-fading, long-term component and a fast-fad in^, short-term component. As a consequenc of the local terrain, the change in a mobile's positioii relative to that of a transmitting €3 will result in periodic nulls in the received signal

is is due to the fact that the vector s u m ~ a t i o ~ of the multipath and scatte~ng

obile C o ~ ~ ~ c a t i o n System Evolution

components at the receiver results in a signal envelope of the form of a standing wave pattern, which has signal nulls at half-wave intervals. For a signal transmitting at 900 typical for cellular applications, a half-wavelength distance c o ~ e s ~ o n d s to 17 cm. This phenomenon is known as slow-fading and is characterised b probability density function.

As the mobile’s velocity, v, increases, the variation in the received becomes much more pronounced and the efTect of the Doppler shift on the received multipath signal compo~ents also has an influence on the received signal, where Doppler shift,&, is given by

V fd = ,cos(a) Hz

where a is the angle of arrival of the incident wave. This phe~omenon is termed fast-fading and is characterised by a ayleigh probability

above the root mean square signal level, although such extremes occur

In rural areas, where the density of users is relatively low, large cells of about 25 km radius

. Such variations in received signal strength can be as much as 30 d

can be employed to provide service coverage. This was indeed the scenario when communications were first introduced into service. In order to sustain the mobile to over such a distance requires the use of a vehicular-type mobile t e ~ n a l , where available transmit power is not so constrained in comparison with hand-held devices. With an increase in user-density~ the cell size needs to reduce in order to enable a greater frequency re-use and hence to increase the capacity of the network. Urban cells are typically of S km radius. This reduction in cell size will also correspond to a reduction in BS and mobile terminal t rans~i t power requirements. This is p~icu lar ly impo~ant in the latter case, since it paves the way for the introduction of hand-held terminals.

When a mobile moves from one cell to another during the course of an o handover (also termed handoff) of the call between BSs must be performed in that the call continues without in te~pt ion . Otherwise the call will be dropped and the mobile user would need to re-initiate the call set-up sequence. Handover between monitoring of the signal strength between the mobile to 13s link. Once the s

*

en t~eshold, the network initiates a procedure to reserve a channel which can provide a channel of sufficient signal strength (Figure S.2).

are clustered together via a fixed-network connection to a mobile switch- hich provides the switching functionality between

and can also provide connection to the fixed or core network (CN) to a1 calls. The clustering of BSs around a MSC is used to define a Location Area, which can be used to determine the latest known location of a mobile user. This is achieved by associatin

me and Vi ation regis

tion Areas to a mobile. Each mobile is registered with a single ho upon joining the network. Once a mobile roams outside of its Home

rs with the network ) associated with the ~ o ~ i l e ’ s loca~ion is

some of which is then forwarded to the VLR. The network also comprises of other d~tabases

Location Area into a new designated Location Area, it tempor re its details are stored in a visitor location reg

network has an associated VLR and , a database containing various info

Basic cellular network architecture,

that can be used to verify that the mobile has access to the network, such as the

system. ), for example. These procedures are described later in the chapter for the

ion society, where mobile~multimedia delivery will be the major force, analogue cellular te~hnology has little, if

ss Europe, mobile digital t ec~no lo~y .

role in many countries around the mobile voice telepho~y at a compe

y s t e ~ s that can still be found with s ign i~c~n t custo

communication facilities

rt of 180 c h ~ n ~ l s . Since it the development of the

own city based ~ o ~ i ~ e for and-h~ld and port c o ~ ~ o d a t e higher data rates

ered an i ~ p o ~ a n t and necessa~

to provide ~ ~ a l - b a n d phones in order to s

the phone? s e v ~ l ~ t i o n forward.

e s y s t ~ ~ o ~ e ~ a t e s in

is at 10 kbitls ernpl

Mobile Satellite ~ o ~ u n i c a t i o n ~ e t w o r ~ s

C) and reverse voice channel ( VC); and to the mobile using the channels 1 channel (FOCC) and forward oice channel ( W C ) . and reverse control channels are used exclusively for network control infor-

mation and can be referred to as Common Control Channels. To safeguard control channels from the effect of the mobile channel, information is protected using concatenated pairs of block codes. To further protect information, an inner code employs multipl~ repetition of

ose-Chadhuri-Hocquenghem) code word at least five times, and 11 times for

In order to identify the S assigned to a call, AMPS employs a s u p e ~ i s o ~ audio tone (SAT), which can be one of three frequencies (5970, 6000 and 6030 Hz). At call set-up, a mobile terminal is i n f o ~ e d of the SAT at the BS to which it communicates. During a call, the mobile terminal continuously monitors the SAT injected by the BS. The S also monitors the same SAT injected by the mobile terminal. Should the received SAT be incorrect at either the mobile terminal or the BS, the signal is muted, since this would imply reception of a source of inte~erence.

standard has continued to evolve and r e m ~ n s orld. Although market penetration did not reach

in its unmodifie~ form, it remains a dominant standard in the Americas and Asia.

Motorola developed the na~owband- available capacity offered by the net 30 H z AMPS channel into three. N- imum deviation of 5 M z from the carrier. From the

phones were developed for dual-mode operation allowing operation with the channel.

employs frequency

er band~idth, there is a slight de~radation in speech quality when In order to optimise reception, N - A ~ P S e ~ p l o y s a radio r e s o ~ c e

~ a n a g e ~ e n t technique called ~ o ~ i Z e ~ e ~ o ~ t e ~ I ~ t e ~ e r e ~ c e . This procedure involves the le t e ~ i n a l ~onitoring the received signal strength of a fo on the control signals of the associated control channel.

decision threshold on the reserve associated control channel, be

nalling control channels are transmitted using a continuous 100 bids in-band su~-audible signal. In addition to signalling messages, a l p h a n u ~ e ~ c ~essages can also smitted to the mobile.

combined with the N was standardised in 1992 under IS-88, I

~ O S , most of ~ e s t e r n Europe had to adopt its own system. For exam

Mobile Com~unication System Evolution

nically compatible systems, in~oduced the TACS into service in January 1985. TACS was based on the American channel spacing. TACS

~etween the two operators. Twenty-one of these channels are ded per operator. The system was developed with the aim of serving hi as well as rural areas. This necessitated the use of a small cell siz

S standard with modifications to the operating fr a capacity of 600 channels in the bands 8 9 ~ 9 0 ~

93~-950 MHz (BS to mobile), the available bandwidth being d d for control channels populated urban areas

an areas of 1 km. In cell size ranges from

modulation with a 9.5 10 Ism. TACS provides a channel spacing of

z peak deviation for voice signals. In highly populated regions, the number of available channels is increased to up to 640 (320 channels per operator) by and Telegraphs

ng the available spectrum to below the conferenc cellular band. This is known as extended TACS

ands are 917-933 M

TACS was first in~oduced into the UK, the combined Vodafone and Cellnet customer base ~ o u n t e d to just under half a million subscribers out of a total of 31 million, The future of analogue technology in developed markets is clearly limited, larly with the r e - f ~ n g of the spectrum for the 3 6 services. Neve~heless, ~ a l o g u e S

have been responsible for developing the mobile culture and in this respect, on to the evolution of the mobile society remains significant.

ithin Europe, TACS networks can also be found in Austria, A%erb~jan, Ireland, Italy, alta and Sp~in. A variant of TACS, known as J-TACS, operates in ~apan.

~ollowing a proposal by Nordic Telecom and etherl lands ) study group was formed in 1982 by the C

pan-European public land mobile system. . The aim of this study

y the middle of the 1 80s, the mobile industry’s attention had focused on the need to implem~nt more spectrally e ~ c i e n t 2 6 digital type services, offering a number of adv~tages includin~ greater immunity to interference, increased security and the of provi~ing a wider range of services. Unlike the evolution of the North Americ which will be discussed shortly, the implementation of CSM took a more revolution^ approach to its design and implementation.

perators and a ~ ~ n i s t r a t o r s signed the GSM memorandum of un~erstandin ent and the original French name was changed to the more descriptive bile communications (GSM), although the acronym remained the sa

1999, 296 operators and administrators from 1 10 countries had signed the Si~ni~cantly, in 198’7, following the evaluation of several candidate technologies laborato~ and field trial experiments, agreement was reached on the use of a regul excitation- line^ predictive coder (R the multiple access method.

In 1989 responsibility for the year later Phase 1

C) for speech coding and TD

ecification was transfe~ed to the speci~cations were published. Commercial GS

Mobile Satellite C o ~ ~ u n i c ~ t i o n ~ e t w o r ~ s

popular in Europe, with the transmission of in excess of 1

services.

h at e ~ ~ l o i t i ~ ~ the poten~al markets in the mobile data the Internet on mobile technologies.

in each band was initially reserved for the in~oduction of

to limit a~jacent channe~ interf~re~ce). nal class, as s h o ~ n in Table 1.1. The power level can

e power control is ality of the mobile

ower level should be adjusted. r a n ~ i n ~ from 2.5 to 320 W i

catego~sed, in a simi

GSM terminal classes

Class Peak ~ a n s ~ i t Peak t rans~i t power (vv)

1 20 2 8 3 5 4 2 5 0.8

43 39 37 33 29

obile ~ o m m u n i c a t i o ~

its in total. These bits are then subje

vice i s fed into the c ~ a ~ n ~ l coder, ~ h i c h

at: 1

GSM TDMA 26-frame structure.