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WIRELESS NETWORKS
P. Nicopolitidis
Aristotle University, Greece
M. S. Obaidat
Monmouth University, USA
G. I. Papadimitriou
Aristotle University, Greece
A. S. Pomportsis
Aristotle University, Greece
JOHN WILEY & SONS, LTD
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To My Parents
Petros Nicopolitidis
To My Mother and the Memory of My Late Father
Mohammad Salameh Obaidat
To My Parents Zoi and Ilias,
To My Wife Maria and our Children
Georgios I. Papadimitriou
To My Sons Sergios and George
Andreas S. Pomportsis
Contents
Preface xv
1 Introduction to Wireless Networks 1
1.1 Evolution of Wireless Networks 2
1.1.1 Early Mobile Telephony 2
1.1.2 Analog Cellular Telephony 3
1.1.3 Digital Cellular Telephony 4
1.1.4 Cordless Phones 7
1.1.5 Wireless Data Systems
1.1.6 Fixed Wireless Links 11
1.1.7 Satellite Communication Systems 11
1.1.8 Third Generation Cellular Systems and Beyond 12
1.2 Challenges 12
1.2.1 Wireless Medium Unreliability 13
1.2.2 Spectrum Use 13
1.2.3 Power Management 13
1.2.4 Security 14
1.2.5 Location/Routing 14
1.2.6 Interfacing with Wired Networks 14
1.2.7 Health Concerns 14
1.3 Overview 15
1.3.1 Chapter 2: Wireless Communications Principles and Fundamentals 15
1.3.2 Chapter 3: First Generation (1G) Cellular Systems 16
1.3.3 Chapter 4: Second Generation (2G) Cellular Systems 16
1.3.4 Chapter 5: Third Generation (3G) Cellular Systems 17
1.3.5 Chapter 6: Future Trends: Fourth Generation (4G) Systems and Beyond 18
1.3.6 Chapter 7: Satellite Networks 19
1.3.7 Chapter 8: Fixed Wireless Access Systems 19
1.3.8 Chapter 9: Wireless Local Area Networks 20
1.3.9 Chapter 10: Wireless ATM and Ad Hoc Routing 21
1.3.10 Chapter 11: Personal Area Networks (PANs) 21
1.3.11 Chapter 12: Security Issues in Wireless Systems 22
1.3.12 Chapter 13: Simulation of Wireless Network Systems 22
1.3.13 Chapter 14: Economics of Wireless Networks 23
WWW Resources 23
References 23
2 Wireless Communications Principles and Fundamentals 25
2.1 Introduction 25
2.1.1 Scope of the Chapter 26
2.2 The Electromagnetic Spectrum 26
2.2.1 Transmission Bands and their Characteristics 27
2.2.2 Spectrum Regulation 30
7
2.3 Wireless Propagation Characteristics and Modeling 32
2.3.1 The Physics of Propagation 32
2.3.2 Wireless Propagation Modeling 36
2.3.3 Bit Error Rate (BER) Modeling of Wireless Channels 41
2.4 Analog and Digital Data Transmission 41
2.4.1 Voice Coding 43
2.5 Modulation Techniques for Wireless Systems 46
2.5.1 Analog Modulation 47
2.5.2 Digital Modulation 49
2.6 Multiple Access for Wireless Systems 54
2.6.1 Frequency Division Multiple Access (FDMA) 55
2.6.2 Time Division Multiple Access (TDMA) 56
2.6.3 Code Division Multiple Access (CDMA) 58
2.6.4 ALOHA-Carrier Sense Multiple Access (CSMA) 59
2.6.5 Polling Protocols 61
2.7 Performance Increasing Techniques for Wireless Networks 67
2.7.1 Diversity Techniques 67
2.7.2 Coding 71
2.7.3 Equalization 74
2.7.4 Power Control 75
2.7.5 Multisubcarrier Modulation 76
2.8 The Cellular Concept 77
2.8.1 Mobility Issues: Location and Handoff 80
2.9 The Ad Hoc and Semi Ad Hoc Concepts 81
2.9.1 Network Topology Determination 82
2.9.2 Connectivity Maintenance 83
2.9.3 Packet Routing 84
2.9.4 The Semi Ad Hoc Concept 84
2.10 Wireless Services: Circuit and Data (Packet) Mode 85
2.10.1 Circuit Switching 85
2.10.2 Packet Switching 86
2.11 Data Delivery Approaches 87
2.11.1 Pull and Hybrid Systems 88
2.11.2 Push Systems 88
2.11.3 The Adaptive Push System 89
2.12 Overview of Basic Techniques and Interactions Between the Different Network Layers 90
2.13 Summary 92
WWW Resources 92
References 93
Further Reading 94
3 First Generation (1G) Cellular Systems 95
3.1 Introduction 95
3.1.1 Analog Cellular Systems 96
3.1.2 Scope of the Chapter 97
3.2 Advanced Mobile Phone System (AMPS) 97
3.2.1 AMPS Frequency Allocations 97
3.2.2 AMPS Channels 98
3.2.3 Network Operations 99
3.3 Nordic Mobile Telephony (NMT) 102
3.3.1 NMT Architecture 102
3.3.2 NMT Frequency Allocations 103
3.3.3 NMT Channels 103
3.3.4 Network Operations: Mobility Management 104
3.3.5 Network Operations 106
viii Contents
3.3.6 NMT Security 107
3.4 Summary 109
WWW Resources 109
References 109
4 Second Generation (2G) Cellular Systems 111
4.1 Introduction 111
4.1.1 Scope of the Chapter 113
4.2 D-AMPS 113
4.2.1 Speech Coding 114
4.2.2 Radio Transmission Characteristics 114
4.2.3 Channels 115
4.2.4 IS-136 116
4.3 cdmaOne (IS-95) 117
4.3.1 cdmaOne Protocol Architecture 117
4.3.2 Network Architecture-Radio Transmission 118
4.3.3 Channels 118
4.3.4 Network Operations 120
4.4 GSM 121
4.4.1 Network Architecture 122
4.4.2 Speech Coding 125
4.4.3 Radio Transmission Characteristics 125
4.4.4 Channels 129
4.4.5 Network Operations 129
4.4.6 GSM Authentication and Security 132
4.5 IS-41 133
4.5.1 Network Architecture 133
4.5.2 Inter-system Handoff 134
4.5.3 Automatic Roaming 135
4.6 Data Operations 136
4.6.1 CDPD 136
4.6.2 HCSD 138
4.6.3 GPRS 138
4.6.4 D-AMPS1 139
4.6.5 cdmaTwo (IS-95b) 140
4.6.6 TCP/IP on Wireless-Mobile IP 140
4.6.7 WAP 142
4.7 Cordless Telephony (CT) 143
4.7.1 Analog CT 143
4.7.2 Digital CT 144
4.7.3 Digital Enhanced Cordless Telecommunications Standard (DECT) 144
4.7.4 The Personal Handyphone System (PHS) 147
4.8 Summary 147
WWW Resources 148
References 148
5 Third Generation (3G) Cellular Systems 151
5.1 Introduction 151
5.1.1 3G Concerns 153
5.1.2 Scope of the Chapter 154
5.2 3G Spectrum Allocation 154
5.2.1 Spectrum Requirements 154
5.2.2 Enabling Technologies 157
5.3 Third Generation Service Classes and Applications 158
Contents ix
5.3.1 Third Generation Service Classes 159
5.3.2 Third Generation Applications 160
5.4 Third Generation Standards 161
5.4.1 Standardization Activities: IMT-2000 161
5.4.2 Radio Access Standards 162
5.4.3 Fixed Network Evolution 183
5.5 Summary 185
WWW Resources 186
References 186
6 Future Trends: Fourth Generation (4G) Systems and Beyond 189
6.1 Introduction 189
6.1.2 Scope of the Chapter 190
6.2 Design Goals for 4G and Beyond and Related Research Issues 190
6.2.1 Orthogonal Frequency Division Multiplexing (OFDM) 192
6.3 4G Services and Applications 195
6.4 Challenges: Predicting the Future of Wireless Systems 196
6.4.1 Scenarios: Visions of the Future
6.4.2 Trends for Next-generation Wireless Networks 197
6.4.3 Scenario 1: Anything Goes 198
6.4.4 Scenario 2: Big Brother 199
6.4.5 Scenario 3: Pocket Computing 200
6.5 Summary 200
WWW Resources 201
References 201
7 Satellite Networks 203
7.1 Introduction 203
7.1.1 Historical Overview 203
7.1.2 Satellite Communications Characteristics 204
7.1.3 Spectrum Issues 205
7.1.4 Applications of Satellite Communications 206
7.1.5 Scope of the Chapter 207
7.2 Satellite Systems 207
7.2.1 Low Earth Orbit (LEO) 208
7.2.2 Medium Earth Orbit (MEO) 209
7.2.3 Geosynchronous Earth Orbit (GEO) 210
7.2.4 Elliptical Orbits 212
7.3 VSAT Systems 213
7.4 Examples of Satellite-based Mobile Telephony Systems 215
7.4.1 Iridium 215
7.4.2 Globalstar 220
7.5 Satellite-based Internet Access 222
7.5.1 Architectures 222
7.5.2 Routing Issues 224
7.5.3 TCP Enhancements 225
7.6 Summary 226
WWW Resources 227
References 228
Further Reading 228
x Contents
Further Reading 18
197
7
8 Fixed Wireless Access Systems 229
8.1 Wireless Local Loop versus Wired Access 229
8.2 Wireless Local Loop 231
8.2.1 Multichannel Multipoint Distribution Service (MMDS) 231
8.2.2 Local Multipoint Distribution Service (LMDS) 232
8.3 Wireless Local Loop Subscriber Terminals (WLL) 234
8.4 Wireless Local Loop Interfaces to the PSTN 234
8.5 IEEE 802.16 Standards 235
8.6 Summary 237
References 238
9 Wireless Local Area Networks 239
9.1 Introduction 239
9.1.1 Benefits of Wireless LANs 240
9.1.2 Wireless LAN Applications 240
9.1.3 Wireless LAN Concerns 241
9.1.4 Scope of the Chapter 243
9.2 Wireless LAN Topologies 243
9.3 Wireless LAN Requirements 245
9.4 The Physical Layer 247
9.4.1 The Infrared Physical Layer 247
9.4.2 Microwave-based Physical Layer Alternatives 249
9.5 The Medium Access Control (MAC) Layer 256
9.5.1 The HIPERLAN 1 MAC Sublayer 257
9.5.2 The IEEE 802.11 MAC Sublayer 260
9.6 Latest Developments 267
9.6.1 802.11a 267
9.6.2 802.11b 267
9.6.3 802.11g 268
9.6.4 Other Ongoing Activities within Working Group 802.11 268
9.7 Summary 269
WWW Resources 271
References 271
Further Reading 272
10 Wireless ATM and Ad Hoc Routing 273
10.1 Introduction 273
10.1.1 ATM 273
10.1.2 Wireless ATM 275
10.1.3 Scope of the Chapter 276
10.2 Wireless ATM Architecture 276
10.2.1 The Radio Access Layer 277
10.2.2 Mobile ATM 278
10.3 HIPERLAN 2: An ATM Compatible WLAN 280
10.3.1 Network Architecture 280
10.3.2 The HIPERLAN 2 Protocol Stack 281
10.4 Routing in Wireless Ad Hoc Networks 287
10.4.1 Table-driven Routing Protocols 288
10.4.2 On-demand Routing Protocols 291
10.5 Summary 295
WWW Resources 296
References 296
Contents xi
11 Personal Area Networks (PANs) 299
11.1 Introduction to PAN Technology and Applications 299
11.1.1 Historical Overview 299
11.1.2 PAN Concerns 301
11.1.3 PAN Applications 302
11.1.4 Scope of the Chapter 303
11.2 Commercial Alternatives: Bluetooth 303
11.2.1 The Bluetooth Specification 303
11.2.2 The Bluetooth Radio Channel 306
11.2.3 Piconets and Scatternets 307
11.2.4 Inquiry, Paging and Link Establishment 309
11.2.5 Packet Format 310
11.2.6 Link Types 311
11.2.7 Power Management 313
11.2.8 Security 314
11.3 Commercial Alternatives: HomeRF 315
11.3.1 HomeRF Network Topology 316
11.3.2 The HomeRF Physical Layer 318
11.3.3 The HomeRF MAC Layer 318
11.4 Summary 323
WWW Resources 325
References 325
Further Reading 325
12 Security Issues in Wireless Systems 327
12.1 The Need for Wireless Network Security 327
12.2 Attacks on Wireless Networks 328
12.3 Security Services 330
12.4 Wired Equivalent Privacy (WEP) Protocol 331
12.5 Mobile IP 334
12.6 Weaknesses in the WEP Scheme 335
12.7 Virtual Private Network (VPN) 336
12.7.1 Point-to-Point Tunneling Protocol (PPTP) 337
12.7.2 Layer-2 Transport Protocol (L2TP) 337
12.7.3 Internet Protocol Security (IPSec) 338
12.8 Summary 338
References 339
13 Simulation of Wireless Network Systems 341
13.1 Basics of Discrete-Event Simulation 341
13.1.1 Subsystem Modeling 344
13.1.2 Variable and Parameter Estimation 344
13.1.3 Selection of a Programming Language/Package 344
13.1.4 Verification and Validation (V&V) 344
13.1.5 Applications and Experimentation 345
13.2 Simulation Models 346
13.3 Common Probability Distributions Used in Simulation 348
13.4 Random Number Generation 351
13.4.1 Linear-Congruential Generators (LCG) 351
13.4.2 Midsquare Method 352
13.4.3 Tausworthe Method 352
13.4.4 Extended Fibonacci Method 352
13.5 Testing Random Number Generators 353
13.6 Random Variate Generation 354
xii Contents
13.6.1 The Inverse Transformation Technique 355
13.6.2 Rejection Method 355
13.6.3 Composition Technique 356
13.6.4 Convolution Technique 356
13.6.5 Characterization Technique 357
13.7 Case Studies 357
13.7.1 Example 1: Performance Evaluation of IEEE 802.11 WLAN Configurations Using
Simulation 357
13.7.2 Example 2: Simulation Analysis of the QoS in IEEE 802.11 WLAN System 360
13.7.3 Example 3: Simulation Comparison of the TRAP and RAP Wireless LANs Protocols 366
13.7.4 Example 4: Simulation Modeling of Topology Broadcast Based on Reverse-Path
Forwarding (TBRPF) Protocol Using an 802.11 WLAN-based MONET Model 372
13.7 Summary 378
References 378
14 Economics of Wireless Networks 381
14.1 Introduction 381
14.1.1 Scope of the Chapter 382
14.2 Economic Benefits of Wireless Networks 382
14.3 The Changing Economics of the Wireless Industry 383
14.3.1 Terminal Manufacturers 383
14.3.2 Role of Governments 384
14.3.3 Infrastructure Manufacturers 385
14.3.4 Mobile Carriers 385
14.4 Wireless Data Forecast 387
14.4.1 Enabling Applications 387
14.4.2 Technological Alternatives and their Economics 388
14.5 Charging Issues 388
14.5.1 Mobility Charges 389
14.5.2 Roaming Charges 391
14.5.3 Billing: Contracts versus Prepaid Time 391
14.5.4 Charging 393
14.6 Summary
References 397
Further Reading 397
Index 399
Contents xiii
396
Preface
The field of wireless networks has witnessed tremendous growth in recent years and it has
become one of the fastest growing segments of the telecommunications industry. Wireless
communication systems, such as cellular, cordless and satellite phones as well as wireless
local area networks (WLANs) have found widespread use and have become an essential tool
to many people in every-day life. The popularity of wireless networks is so great that we will
soon reach the point where the number of worldwide wireless subscribers will be higher than
the number of wireline subscribers. This popularity of wireless communication systems is due
to its advantages compared to wireline systems. The most important of these advantages is the
freedom from cables, which enables the 3A paradigm: communication anywhere, anytime,
with anyone. For example, by dialing a friend or colleague’s mobile phone number, one is
able to contact him in a variety of geographical locations, thus overcoming the disability of
fixed telephony.
This book aims to provide in-depth coverage of the wireless technological alternatives
offered today. In Chapter 1, a short introduction to wireless networks is made.
In Chapter 2, background knowledge regarding wireless communications is provided.
Issues such as electromagnetic wave propagation, modulation, multiple access for wireless
systems, etc. are discussed Readers who are already familiar with these issues may skip this
chapter.
In Chapter 3, the first generation of cellular systems is discussed. Such systems are still
used nowadays, nevertheless they are far from being at the edge of technology. Chapter 3
discusses two representative first generation systems, the Advanced Mobile Phone System
(AMPS) and the Nordic Mobile Telephony (NMT) system.
In Chapter 4, the second generation of cellular systems is discussed. The era of mobile
telephony as we understand it today, is dominated by second generation cellular standards.
Chapter 4 discusses several such systems, such as D-AMPS, cdmaOne and the Global system
for Mobile Communications (GSM). Moreover, data transmission over 2G systems is
discussed by covering the so-called 2.5G systems, such as the General Packet Radio Service
(GPRS), cdmaTwo, etc. Finally, Chapter 4 discusses Cordless Telephony (CT) including the
the Digital European Cordless Telecommunications Standard (DECT) and the Personal
Handyphone System (PHS) standards.
Chapter 5 discusses the third generation of cellular systems. These are the successors of
second generation systems. They are currently starting to be deployed and promise data rates
up to 2 Mbps. The three different third generation air-interface standards (Enhanced Data
Rates for GSM Evolution (EDGE), cdma2000 and wideband CDMA (WCDMA)) are
discussed.
Chapter 6 provides a vision of 4G and beyond mobile and wireless systems. Such systems
target the market of 2010 and beyond, aiming to offer data rates of at least 50 Mbps. Due to
the large time window to their deployment, both the telecommunications scene and the
services offered by 4G systems and beyond are not yet known and as a result aims for
these systems may be changing over time.
Chapter 7 discusses satellite-based wireless systems. After discussing the characteristics of
the various satellite orbits, Chapter 7 covers the VSAT, Iridium and Globalstar systems and
discusses a number of issues relating to satellite-based Internet access.
Chapter 8 discusses fixed wireless systems. The main points of this chapter are the wellknown Multichannel Multipoint Distribution Service (MMDS) and Local Multipoint Distribution Service (LMDS).
Chapter 9 covers wireless local area networks. It discusses the design goals for wireless
local area networks, the different options for using a physical layer and the MAC protocols of
two wireless local area network standards, IEEE 802.11 and ETSI HIPERLAN 1. Furthermore, it discusses the latest developments in the field of wireless local area networks.
Chapter 10 is devoted to Wireless Asynchronous Transfer Mode (WATM). After providing
a brief introduction to ATM, it discusses WATM and HIPELRAN 2, an ATM-compatible
wireless local area network. The chapter also provides a section on wireless ad-hoc routing
protocols.
Chapter 11 describes Personal Area Networks (PANs). The concept of a PAN differs from
that of other types of data networks in terms of size, performance and cost. PANs target
applications that demand short-range communications. After a brief introduction, Chapter 11
covers the Bluetooth and HomeRF PAN standards.
Chapter 12 discusses security issues in wireless networks. Security is a crucial point in all
kinds of networks but is even more crucial in wireless networks due to the fact that wireless
transmission cannot generally be confined to a certain geographical area.
Chapter 13 deals with the basics of simulation modeling and its application to wireless
networking. It discusses the basic issues involved in the development of a simulator and
presents several simulation studies of wireless network systems.
Finally, Chapter 14 discusses several economical issues relating to wireless networks. It is
reported that although voice telephony will continue to be a significant application, the
wireless-Internet combination will shift the nature of wireless systems from today’s voiceoriented wireless systems towards data-centric ones. The impacts of this change on the key
players in the wireless networking world are discussed. Furthermore, the chapter covers
charging issues in the wireless networks.
We would like to thank the reviewers of the original book proposal for their constructive
suggestions. Also, we would like to thank our students for some feedback that we received
while trying the manuscript in class. Many thanks to Wiley’s editors and editorial assistants
for their outstanding work.
xvi Wireless Networks
1
Introduction to Wireless
Networks
Although it has history of more than a century, wireless transmission has found widespread
use in communication systems only in the last 15–20 years. Currently the field of wireless
communications is one of the fastest growing segments of the telecommunications industry.
Wireless communication systems, such as cellular, cordless and satellite phones as well as
wireless local area networks (WLANs) have found widespread use and have become an
essential tool in many people’s every-day life, both professional and personal. To gain insight
into the wireless market momentum, it is sufficient to mention that it is expected that the
number of worldwide wireless subscribers in the years to come will be well over the number
of wireline subscribers. This popularity of wireless communication systems is due to its
advantages compared to wireline systems. The most important of these advantages are
mobility and cost savings.
Mobile networks are by definition wireless, however as we will see later, the opposite is not
always true. Mobility lifts the requirement for a fixed point of connection to the network and
enables users to physically move while using their appliance with obvious advantages for the
user. Consider, for example, the case of a cellular telephone user: he or she is able to move
almost everywhere while maintaining the potential to communicate with all his/her colleagues, friends and family. From the point of view of these people, mobility is also highly
beneficial: the mobile user can be contacted by dialing the very same number irrespective of
the user’s physical location; he or she could be either walking down the same street as the
caller or be thousands of miles away. The same advantage also holds for other wireless
systems. Cordless phone users are able to move inside their homes without having to carry
the wire together with the phone. In other cases, several professionals, such as doctors, police
officers and salesman use wireless networking so that they can be free to move within their
workplace while using their appliances to wirelessly connect (e.g., through a WLAN) to their
institution’s network.
Wireless networks are also useful in reducing networking costs in several cases. This stems
from the fact that an overall installation of a wireless network requires significantly less
cabling than a wired one, or no cabling at all. This fact can be extremely useful:
† Network deployment in difficult to wire areas. Such is the case for cable placement in
rivers, oceans, etc. Another example of this situation is the asbestos found in old buildings.
Inhalation of asbestos particles is very dangerous and thus either special precaution must
be taken when deploying cables or the asbestos must be removed. Unfortunately, both
solutions increase the total cost of cable deployment.
† Prohibition of cable deployment. This is the situation in network deployment in several
cases, such as historical buildings.
† Deployment of a temporary network. In this case, cable deployment does not make sense,
since the network will be used for a short time period.
Deployment of a wireless solution, such as a WLAN, is an extremely cost-efficient solution
for the scenarios described above. Furthermore, deployment of a wireless network takes
significantly less time compared to the deployment of a wired one. The reason is the same:
no cable is installed.
In this introductory chapter we briefly overview the evolution of wireless networks, from
the early days of pioneers like Samuel Morse and Guglielmo Marconi to the big family of
today’s wireless communications systems. We then proceed to briefly highlight the major
technical challenges in implementing wireless networks and conclude with an overview of
the subjects described in the book.
1.1 Evolution of Wireless Networks
Wireless transmission dates back into the history of mankind. Even in ancient times, people
used primitive communication systems, which can be categorized as wireless. Examples are
smoke signals, flashing mirrors, flags, fires, etc. It is reported that the ancient Greeks utilized a
communication system comprising a collection of observation stations on hilltops, with each
station visible from its neighboring one. Upon receiving a message from a neighboring
station, the station personnel repeated the message in order to relay it to the next neighboring
station. Using this system messages were exchanged between pairs of stations far apart from
one another. Such systems were also employed by other civilizations.
However, it is more logical to assume that the origin of wireless networks, as we understand them today, starts with the first radio transmission. This took place in 1895, a few years
after another major breakthrough: the invention of the telephone. In this year, Guglielmo
Marconi demonstrated the first radio-based wireless transmission between the Isle of Wight
and a tugboat 18 miles away. Six years later, Marconi successfully transmitted a radio signal
across the Atlantic Ocean from Cornwall to Newfoundland and in 1902 the first bidirectional
communication across the Atlantic Ocean was established. Over the years that followed
Marconi’s pioneering activities, radio-based transmission continued to evolve. The origins
of radio-based telephony date back to 1915, when the first radio-based conversation was
established between ships.
1.1.1 Early Mobile Telephony
In 1946, the first public mobile telephone system, known as Mobile Telephone System
(MTS), was introduced in 25 cities in the United States. Due to technological limitations,
the mobile transceivers of MTS were very big and could be carried only by vehicles. Thus, it
was used for car-based mobile telephony. MTS was an analog system, meaning that it
processed voice information as a continuous waveform. This waveform was then used to
modulate/demodulate the RF carrier. The system was half-duplex, meaning that at a specific
2 Wireless Networks