Transcript Wireless Communications and Networks

Mobile Networks
Asst. Prof. Dr. Mohammad kaleem
Computer Engineering Department,
National University of Sciences and
Technology, Islamabad
Text Book
•Wireless Communications and
Networks, by William Stallings,
Prentice Hall, 2nd Edition, 2005
•This textbook will be followed for
most of the course.
•The material on multihop and
sensor networks will be taken
from research papers,
and other collections.
Prerequisites
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Computer Communications And Networks
Digital Communications
Introduction
Chapter 1
Wireless Comes of Age
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Guglielmo Marconi invented the wireless
telegraph in 1896
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Communications satellites launched in 1960s
Advances in wireless technology
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Communication by encoding alphanumeric characters
in analog signal
Sent telegraphic signals across the Atlantic Ocean
Radio, television, mobile telephone, communication
satellites
More recently
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Satellite communications, wireless networking, cellular
technology, ad hoc networks, Sensor networks
Broadband Wireless Technology
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Higher data rates obtainable with broadband
wireless technology
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Graphics, video, audio
Shares same advantages of all wireless services:
convenience and reduced cost
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Service can be deployed faster than fixed service
No cost of cable plant
Service is mobile, deployed almost anywhere
Future Generations
Other Tradeoffs:
Rate vs. Coverage
Rate vs. Delay
Rate vs. Cost
Rate vs. Energy
Rate
802.11n
802.11b WLAN
2G
4G
3G
Wimax/3G
2G Cellular
Mobility
Fundamental Design Breakthroughs Needed
Evolution of Current Systems
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Wireless systems today
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Next Generation is in the works
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3G Cellular: ~200-300 Kbps.
WLANs: ~450 Mbps (and growing).
4G Cellular: Likely OFDM/MIMO
4G WLANs: Wide open, 3G just being finalized
Technology Enhancements
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Hardware: Better batteries. Better
circuits/processors.
Link: Antennas, modulation, coding, adaptivity, DSP,
BW.
Network: more efficient resource allocation
Application
Application
Transport
Transport
Network
Network
Data Link
Physical
Network
Network
Data Link
Data Link
Data Link
Physical
Physical
Physical
Radio
Medium
Scope of this course:
Anything above and related protocols
Wireless communication systems
Target information systems: “Anytime,
Anywhere, Anyform”
 Applications: Ubiquitous computing and
information access
 Market in continuous growth:
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35-60% annual growth of PCS
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Number of subscribers:
Services)
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(Personal Communications
by 2001: over 700M mobile phones
by 2003: 1 billion wireless subscribers (source Ericsson)
300% growth in wireless data from 1995-1997
Large diversity of standards and products
 Confusing terminology
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Mobile Subscribers in Pakistan
Customers of Mobile Service Providers in Pakistan*
Year
Mobilin
k
Paktel
Instapho
ne
2000
114,272
80,22
1
2001
309,272
116,711
2002
800,000
2003
Ufone
Telen
or
Total
Growth Rate
112,000
306,493
15.39
96,62
3
220,000
742,606
142.29
350,00
0
218,5
36
330,000
1,698,53
6
128.73
1,115,00
0
550,00
0
319,4
00
420,000
2,404,40
0
41.56
2004
3,215,98
9
801,16
0
470,0
21
535,738
5,022,90
8
108.90
2005
7,469,08
5
2,579,1
03
924,4
86
454,147
12,771,2
03
154.26
14,119,2
57
10.56
15,511,0
45
9.7
835,7
27
Warid
508,65
5
Jul-05
Company wise Data is updated on Quarterly Basis
Aug -05
More than 15,511,045 subscribers of Cellular Networks
*From
Telecom Indicators section of PTA Website
Mobile Subscribers in Pakistan
Warid
2005
2004
Telenor
2003
Instaphone
2002
2001
Paktel
2000
Ufone
Mobilink
0
2,000,000
4,000,000
6,000,000
8,000,000
Limitations and Difficulties of
Wireless Technologies
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Wireless is convenient and less expensive
Limitations and political and technical difficulties
inhibit wireless technologies
Lack of an industry-wide standard
Device limitations
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E.g., small LCD on a mobile telephone can only
displaying a few lines of text
E.g., browsers of most mobile wireless devices use
wireless markup language (WML) instead of HTML
Wireless around us…
WLAN, DAB, GSM,
etc…
Personal Travel Assistant,
PDA, Laptop, GSM, cdmaOne
WLAN, Bluetooth, ...
Radio frequency spectrum
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Wireless technologies have gradually
migrated to higher frequencies
Wireless & Mobility
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Wireless:
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Mobility:
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User location may change with time
Speed of mobile impacts wireless bandwidth
Need mechanism for handoff
Security: easier spoofing
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Limited battery, storage, computing, and GUI
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Limited bandwidth
Broadcast medium: requires multiple access schemes
Variable link quality (noise, interference)
High latency, higher jitter
Heterogeneous air interfaces
Security: easier snooping
Portability
Challenges in Mobile Networking
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Three major challenges:
Wireless Channel
 Mobility
 Device Limitation
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Part One: Background
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Provides preview and context for rest of
book
Covers basic topics
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Data Communications
TCP/IP
Chapter 2: Transmission
Fundamentals
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Basic overview of transmission topics
Data communications concepts
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Includes techniques of analog and digital data
transmission
Channel capacity
Transmission media
Multiplexing
Chapter 3: Communication
Networks
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Comparison of basic communication
network technologies
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Circuit switching
Packet switching
Frame relay
ATM
Chapter 4: Protocols and the
TCP/IP Protocol Suite
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Protocol architecture
Overview of TCP/IP
Open systems interconnection (OSI)
reference model
Internetworking
Part Two: Wireless
Communication Technology
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Underlying technology of wireless
transmission
Encoding of analog and digital data for
wireless transmission
Chapter 5: Antennas and
Propagation
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Principles of radio and microwave
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Antenna performance
Wireless transmission modes
Fading
Chapter 6: Signal Encoding
Techniques
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Wireless transmission
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Analog and digital data
Analog and digital signals
Chapter 7: Spread Spectrum
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Frequency hopping
Direct sequence spread spectrum
Code division multiple access (CDMA)
Chapter 8: Coding and Error
Control
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Forward error correction (FEC)
Using redundancy for error detection
Automatic repeat request (ARQ) techniques
Part Three: Wireless Networking
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Examines major types of networks
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Satellite-based networks
Cellular networks
Cordless systems
Fixed wireless access schemes
Use of mobile IP and Wireless Access
Protocol (WAP) to provide Internet and
Web access
Chapter 9: Satellite
Communications
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Geostationary satellites (GEOS)
Low-earth orbiting satellites (LEOS)
Medium-earth orbiting satellites (MEOS)
Capacity allocation
Chapter 10: Cellular Wireless
Networks
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Cellular wireless network design issues
First generation analog (traditional
mobile telephony service)
Second generation digital cellular networks
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Time-division multiple access (TDMA)
Code-division multiple access (CDMA)
Third generation networks
Chapter 11: Cordless Systems
and Wireless Local Loop
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Cordless systems
Wireless local loop (WLL)
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Sometimes called radio in the loop (RITL) or
fixed wireless access (FWA)
Chapter 12: Mobile IP and
Wireless Access Protocol
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Modifications to IP protocol to
accommodate wireless access to Internet
Wireless Application Protocol (WAP)
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Provides mobile users access to telephony and
information services including Internet and
Web
Includes wireless phones, pagers and personal
digital assistants (PDAs)
Part Four: Wireless Local Area
Networks
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Examines underlying wireless LAN
technology
Examines standardized approaches to local
wireless networking
Chapter 13: Wireless LAN
Technology
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Overview of LANs and wireless LAN
technology and applications
Transmission techniques of wireless LANs
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Spread spectrum
Narrowband microwave
Infrared
Chapter 14: IEEE 802.11
Wireless LAN Standard
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Wireless LAN standards defined by IEEE
802.11 committee
Chapter 15: Bluetooth
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Bluetooth is an open specification for
wireless communication and networking
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Personal computers
Mobile phones
Other wireless devices
Internet and Web Resources
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Web page for this book
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Computer Science Student Support Site
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WilliamStallings.com/Wireless1e.html
Useful web sites, errata sheet, figures, tables, slides,
internet mailing list, wireless courses
WilliamStallings.com/StudentSupport.html
Newsgroups
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comp.std.wireless
comp.dcom.*