Transcript Lecture1(Introduction of WirelessComm)

Wireless Communication
Lecture 2
Tahir Iqbal
[email protected]
Air University, Islamabad
• Text Books:
– Rappaport, Theodore S., “Wireless Communications Principles
and Practice” 2/e, Prentice Hall PTR
– Jochen H. Schiller, “Mobile Communications”, 2nd edition ©
2004, Addison-Wesley
• Reference Books:
– Ulysis Black, “Mobile & Wireless", Printice Hall Co.
– Bud Bates, "Wireless Network Communication", Mc-Graw Hill.
– Asha Melotra, "GSM System Engineering.", Artech house Inc.
London.
– Demy stified, "3G - Wireless ", Mc-Graw Hill.
– Charles Perkins, “Mobile IP”
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Objective of course
• The objective of this course is to familiarize the students
about the fundamentals of Wireless and Mobile
Communications covering the above mentioned topics.
• The course will also introduce the students with the modern
trends in Wireless and Mobile Communications, WAP
Applications, wireless Networks standards, ISDN, GSM
architecture, services, cellular principles, Cross-layer designing
for wireless Network, ad-hoc network, wireless sensor
network and security issues in ah-hoc and wireless sensor
network.
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• The course will mainly cover the following topics:
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Modern Wireless Communication Systems
The Cellular Concepts
Mobile Radio Propagation
Modulation Techniques for mobile radio
Multiple Access techniques for wireless
Communications
– Wireless Networking
– Wireless Systems and Standards
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Grading and General Course Policies
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Visit class folder regularly for course updates, announcements, and for other
course materials. Go to Common=>(Your Class:BETE04…)=>Wireless
Communications
Assignments and/or grade percentages are subject to change. The breakdown is
as follows:
Quizzes
Project(NS2)/Articles
Mid Term
Final
Total
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10%
20%
30%
40%
100%
No makeup tests will be given
No late assignments will be accepted.
Late phase assignments will not be accepted.
All assignments submitted should be the outcome of individual work only. Group
work is explicitly prohibited (severe penalties for violation).
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Some useful Wireless Links
Stanford Course on Advanced Topics in Wireless Communications (Network
Focus).
Wireless and Mobile Networking Course by Y. Altunbasak at Georgia Tech.
Advanced Wireless Class by J. Andrews at UT Austin.
Mobile and Wireless Networks and Applications Course by Mary Baker at
Stanford.
Wireless Information Networks Laboratory Rutgers University.
Berkeley Wireless Research Center University of California at Berkeley.
Center for Wireless Communications University of California at San Diego.
Center for Wireless Information Network Studies Worcester Polytechnic.
Bluetooth Homepage.
Packet Radio Reading List.
Resource and Course Website for William Stallings Book on Wireless
Communications and Networks..
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Organization of the Lecture
1.1) Introduction to Wireless Communication
1.2) An Overview of Applications and Examples of Wireless Communication
1.3) Historical Evolution and Trends in Wireless Communications
1.4) Terminology and Definitions of Wireless Communication Systems
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Why Mobile Communication?
Question: Why do we need a new technology when we have
such a developed public telephone network. The answer is
mobility.
This course is about Wireless Communication, with emphasis on
Mobile (also known as Cellular) Radio Communication
Systems.
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Challenges of mobility
Challenges of using a radio channel:
The use of radio channels necessitates methods of sharing them – channel
access.
The quality of the path - a more challenging problem than with wires.
Bandwidth: it is possible to add wires but not bandwidth. So it is important to
develop technologies that provide for channel reuse.
Privacy and security - a more difficult issue than with wired phone.
Others: low energy (battery), hand off, etc.
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Historical Evolution and Trends in
Wireless Communication
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Early History of Wireless
Communication
Many people in history used light for communication.
1. heliographs, flags (“semaphore”)
2. 150 BC smoke signals (Polybius, Greece)
3. 1794, optical telegraph, Claude Chappe
b. Later on Electromagnetic waves became important:
1. 1831 Faraday demonstrates electromagnetic induction.
2. J. Maxwell (1831- 79): Theory of electromagneticfields, wave equations
(1864)
3. H. Hertz (1857-94): demonstrated the wave character of electrical
transmission through space.
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Historical Background
• Evolution of Voice Oriented Wireless Networks
The origin of wireless communication dates back to the era of
Marconi ---- 1897, when he demonstrated the radio’s communication
ability to provide continuous contact with the ships sailing the English
channel.
– Mobile telephone service was first offered by AT&T in 1946. This
service was mobile, but not cellular. The base station had a coverage
of about 100 km.
– Early systems, based on FM, required 120 KHz of spectrum for an
information bandwidth of 3 kHz. Large equipment (mounted in cars).
Low capacity: 50 users or more cause overloading, 65% blocking
probability. Multiple Access method used was FDMA.
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•
Next step was the introduction of trunking - relaxing the
constraint of using a channel for each user. Frequency-agile
radio to search for free channels.
• Cellular concept emerges in early 1970s. Cellular is not a new
technology but rather a new organization. Replication of the
wide-area network concept. Cellular concept leads to
frequency-reuse concept. By late 60's there we,re 70,000
users throughout US.
• Invention of the microprocessor facilitated the
implementation of the complex control algorithms required
mainly for switching between base stations.
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• Digital control link emerged, regulatory obstacles were
cleared and 1 st generation (1 G) systems were deployed in
1983.
• Early 1990s digital voice was developed - 2nd generation (2G)
systems. Smaller and longer-life batteries. Miniaturization of
the handset
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The current status of Wireless
Communication
• The modern era has seen extremely rapid growth in Wireless
Communication, especially in Cellular communication.
• Nowadays, because of the growth of other parallel
engineering fields, and the state of the art available
technology, Wireless Communication is enjoying the fastest
growth period in history.
• It is also the fastest growing field, by any measure, of today’s
world.
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• There are about 1billion cellular phone users in the world.
• Income of wireless industry surpasses that of wired telephone
industry.
• The Internet brought the computer communications industry
from the office to home.
• The information exchange industry consists of:
– Fixed telephone
– Wireless
– Internet
• It is by far the largest industry in the world
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1982 Deployment of 1st generation Nordic analog NMT
1983 Deployment of US Amps
1988 GSM development
1988 IS-54 development
1988 CDMA development
1991 GSM deployment
1993 IS-95 development
1995 PCS band auctions
1998 3G standardization started
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Personal Communication Systems
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Examples of Mobile Radio Communication
Systems
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Paging
Amateur Radio
Citizen Band (CB) Radio
Cordless Phones
Mobile Telephones
Satellite Phones
Radio Communication with aircrafts and ships
Global Positioning System (GPS)
Wireless Networks (both LANs and WANs)
Personal Communication Systems, such as:
Garage door opener
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Remote Controls for various appliances
Localization / Position Finding Systems
Remote Controlled Vehicles and un-manned planes etc
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Wide Area Paging System
• The paging control center dispatches pages received
from the PSTN throughout several cities at the same
time
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Wide Area Paging System
Landline link
PSTN
Paging
control
center
Landline link
Satellite link
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City 1:
Paging
terminal
City 2:
Paging
terminal
City N:
Paging
terminal
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Paging systems are communication systems
that send brief messages to a subscriber...
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Numeric messages
Alpha-numeric message
Voice message
News headlines
Stock quotes
Faxes
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Paging Systems Coverage Area
• 2 to 5 km
• Within individual buildings
• Worldwide coverage
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Wireless Applications
• Two classes of applications:
– voice oriented
– data oriented
Voice-oriented applications evolved around wireless connections to
PSTN.
• Local area voice oriented:
low-power, low-mobility, high quality voice:
cordless phone, PCS
• Wide area voice oriented:
high-power, high mobility, comprehensive coverage, lower
quality than local area.
cellular wireless
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Wireless Data Applications
• Data oriented:
broadband local and ad hoc, wide area mobile data
market.
• Local – WLANs and wireless personal area networks
(WPANs)
wireless high speed Internet access.
• Wide area
Internet access to mobile users.
• Concept of Mobile IP:
user carries his lap-top while sitting in his car---internet connectivity
via cellular networks
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Terminology
• Mobile - historically, any radio terminal that can
move during operation. More recently, a terminal
attached to a high speed moving platform
• Portable - walking.
• Subscriber- user paying a subscription fee.
• Base station - connected to a commercial power
source and a fixed backbone network.
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• Simplex / half-duplex / full-duplex
• Simplex - one way communication e.g. paging.
• Half duplex - two way communication, using some
radio channel. User can only transmit or receive e.g.
"push-to-talk’’ feature.
• Full duplex - use separate channels. Frequency
division duplexing FDD – uses single antenna with
duplexer.
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Terminology and Definitions
• Control Channel:
– Radio channel used for transmission of call setup, call request, call
initiation and other control purposes.
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Voice Channel:
– Radio channels used for transmission of voice
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Hand-off:
– The process of transferring a mobile station from one channel or base
station to the other during the conversation.
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Roamer:
– A mobile station which operates in a service area other than that from
which service has been subscribed.
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Page:
– A brief message which is broadcast over the entire service area,
usually in a simulcast fashion by many base stations at the same time.
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• Transceiver:
– A device capable of transmitting and receiving radio signals
• Frequency Division Duplexing (FDD):
– Duplexing means transmitting and receiving simultaneously.
When transmitter and receiver use different frequency channels,
it’s called FDD.
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Time Division Duplexing (TDD):
– When Transmitter and Receiver use different Time Slots for
duplexing purposes, this is called TDD.
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