chapter 1 introduction original

8/20/2019 Chapter 1 Introduction Original

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MOBILE

COMPUTINGRoger Wattenhofer

Summer 2004

Distributed

ComputingGroup


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Distributed Computing Group MOBILE COMPUTING R. Wattenhofer 1/3

Overview

• What is it?

• Who needs it?

• History• Future

• Course overview

• Organization of exercises• Literature

• Thanks to J. Schiller for slides

[ D

e r S p i e g e l ]


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A computer in 2010?

• Advances in technology

– More computing power in smaller devices

– Flat, lightweight displays with low power consumption

– New user interfaces due to small dimensions

– More bandwidth (per second? per space?)

– Multiple wireless techniques

• Technology in the background

– Device location awareness: computers adapt to their environment

– User location awareness: computers recognize the location of the

user and react appropriately (call forwarding)

• “Computers” evolve

– Small, cheap, portable, replaceable

– Integration or disintegration?


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What is Mobile Computing?

• Aspects of mobility

– User mobility: users communicate “anytime, anywhere, with anyone”

(example: read/write email on web browser)

– Device portability: devices can be connected anytime, anywhere to the

network

• Wireless vs. mobile Examples Stationary computer Notebook in a hotel

Wireless LANs in historic buildings Personal Digital Assistant (PDA)

• The demand for mobile communication creates the need for

integration of wireless networks and existing fixed networks

– Local area networks: standardization of IEEE 802.11 or HIPERLAN

– Wide area networks: GSM and ISDN

– Internet: Mobile IP extension of the Internet protocol IP


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Application Scenarios

• Vehicles

• Nomadic user

• Smart mobile phone

• Invisible computing

• Wearable computing

• Intelligent house or office

• Meeting room/conference• Taxi/Police/Fire squad fleet

• Service worker

• Lonely wolf

• Disaster relief and Disaster alarm

• Games

• Military / Security

What is important?


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Vehicles

a d h o c

DAB

[J. Schiller]

GSM,

UMTS

GPS


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Vehicles 2

[Der Spiegel]


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Nomadic user

• Nomadic user has laptop/palmtop

• Connect to network infrequently

• Interim period operate in disconnected mode

• Access her or customer data

• Consistent database for all agents

• Print on local printer (or other service)

– How do we find it?

– Is it safe? – Do we need wires?

• Does nomadic user need her own hardware?

• Read/write email on web browser • Access data OK too


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B u i l t

1 5 0 B C

Smart mobile phone

• Mobile phones get smarter

• Converge with PDA?

• Voice calls, video calls (really?)

• Email or instant messaging

• Play games

• Up-to-date localized information

– Map – Pull: Find the next Pizzeria

– Push: “Hey, we have great Pizza!”

• Stock/weather/sports info

• Ticketing• Trade stock

• etc.

[Nokia]

[J. Schiller]


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Invisible/ubiquitous/pervasive and wearable computing

• Tiny embedded “computers”

• Everywhere

• Example: Microsoft’s Doll

• I refer to my colleagues

Friedemann Mattern and

Bernt Schiele and their

courses

[ABC, Schiele]


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Intelligent Office and Intelligent House

• Bluetooth replaces cables

• Plug and play, without the “plug”

• Again: Find the local printer

• House recognizes inhabitant

• House regulates temperature

according to person in a room

• Trade Shows

• Home without cables looks better

• LAN in historic buildings [MS]


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Meeting room or Conference

• Share data instantly

• Send a message to someone

else in the room

• Secretly vote on controversial

issue

• Find person with similar interests

• Broadcast last minute changes

• Ad-Hoc Network


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Taxi / Police / Fire squad / Service fleet

• Connect

• Control

• Communicate

• Service Worker

• Example: SBB service workers

have PDA

– Map help finding broken signal

– PDA gives type of signal, so that

service person can bring the right

tools right away


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Lonely wolf

• We really mean everywhere!

• Cargo’s and yachts

• Journalists

• Scientists

• Travelers

• Sometimes cheaper than

infrastructure?

• Commercial flop [Motorola]


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Disaster relief

• After earthquake, tsunami,

volcano, etc:

• You cannot rely on

infrastructure but you need toorchestrate disaster relief

• Early transmission of patient

data to hospital

• Satellite

• Ad-Hoc network

[Red Cross]


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Disaster alarm

• With sensors you might be

able to alarm early

• Example: Tsunami

• Example: Cooling room

• Or simpler: Weather station

• Satellite

• Ad-Hoc network


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Application Scenarios: Discussion

• Vehicles

• Nomadic user

• Smart mobile phone

• Invisible computing

• Wearable computing

• Intelligent house or office

• Meeting room/conference

• Taxi/Police/Fire squad fleet• Service worker

• Lonely wolf

• Disaster relief and Disaster alarm

• Games• Military / Security

• Anything missing?

What do you like?


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Mobile devices

performance and sizeperformance and size

Pager

• receive only

• tiny displays

• simple text

messages

Mobile phone

• voice, data

• simple text display

PDA

• simple graphical displays

• character recognition

• simplified WWW

Palmtop• tiny keyboard

• simple versions

of standard applications

Laptop

• fully functional

• standard applications

Sensors,

embedded

controllers


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Effects of device portability

• Energy consumption

– there is no Moore’s law for batteries or solar cells

– limited computing power, low quality displays, small disks

– Limited memory (no moving parts)

– Radio transmission has a high energy consumption

– CPU: power consumption ~ CV2f

• C: total capacitance, reduced by integration

• V: supply voltage, can be reduced to a certain limit

• f: clock frequency, can be reduced temporally• Limited user interfaces

– compromise between size of fingers and portability

– integration of character/voice recognition, abstract symbols

• Loss of data – higher probability (e.g., defects, theft)


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Wireless networks in comparison to fixed networks

• Higher loss-rates due to interference – emissions of, e.g., engines, lightning

• Restrictive regulations of frequencies

– frequencies have to be coordinated, useful frequencies are almost all

occupied

• Low transmission rates

– local some Mbit/s, regional currently, e.g., 9.6kbit/s with GSM

• Higher delays, more jitter

– connection setup time with GSM in the second range, several hundredmilliseconds for other wireless systems, tens of seconds with Bluetooth

• Lower security, simpler active attacking

– radio interface accessible for everyone, base station can be simulated,

thus attracting calls from mobile phones• Always shared medium

– secure access mechanisms important


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History: Antiquity – 1890

• Many people in history usedlight for communication

– Heliographs (sun on mirrors),

flags („semaphore“), ...

– 150 BC: smoke signals forcommunication (Polybius, Greece)

– 1794: Optical telegraph by Claude Chappe

• Electromagnetic waves – 1831: Michael Faraday (and Joseph Henry)demonstrate electromagnetic induction

– 1864: James Maxwell (1831-79): Theory of

electromagnetic fields, wave equations

– 1886: Heinrich Hertz (1857-94): demonstrateswith an experiment the wave character

of electrical transmission through space


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History: 1920 – 1945

• 1920: Discovery of short waves by Marconi

– reflection at the ionosphere

– smaller sender and receiver

– Possible with vacuum tube

• 1926: First phone on a train

– Hamburg – Berlin

– wires parallel to the railroad track

• 1926: First car radio

• 1928: First TV broadcast

– John L. Baird (1888 – 1946)

– Atlantic, color TV

– WGY Schenectady

• 1933: Frequency modulation

– Edwin H. Armstrong (1890 – 1954)


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History: 1945 – 1980

• 1958: German A-Netz

– Analog, 160MHz, connection setup

only from mobile station, no handover,

80% coverage, 16kg, 15k Marks

– 1971: 11000 customers

– Compare with PTT (Swisscom) NATEL:

1978 – 1995, maximum capacity

4000, which was reached 1980

• 1972: German B-Netz – Analog, 160MHz, connection setup from the fixed network too (but

location of the mobile station has to be known)

– available also in A, NL and LUX, 1979 13000 customer in D

– PTT NATEL B: 1984 – 1997, maximum capacity 9000

• 1979: NMT Nordic Mobile Telephone System

– 450MHz (Scandinavia)

[F.Mattern]


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History: 1980 – 1991

• 1982: Start of GSM-specification (Groupe spéciale mobile) – goal: pan-European digital mobile phone system with roaming

• 1984: CT-1 standard for cordless telephones

• 1986: German C-Netz

– analog voice transmission, 450MHz, hand-over possible, digitalsignaling, automatic location of mobile device

– still in use today, services: FAX, modem, X.25, e-mail, 98%

coverage

– American AMPS: 1983 – today – PTT NATEL C: 1986 – 1999

• 1991: DECT

– Digital European Cordless Telephone. Today: “Enhanced”

– 1880-1900MHz, ~100-500m range, 120 duplex channels, 1.2Mbit/sdata transmission, voice encryption, authentication, up to several

10000 users/km2, used in more than 40 countries


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History: 1991 – 1995

• 1992/3: Start of GSM “D-Netz”/“NATEL D” – 900MHz, 124 channels

– automatic location, hand-over, cellular

– roaming in Europe

– now worldwide in more than 130 countries – services: data with 9.6kbit/s, FAX, voice, ...

• 1994/5: GSM with 1800MHz

– smaller cells

– supported by

many countries

– SMS

– Multibandphones


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History: 1995 – today

• 1996: HiperLAN – High Performance Radio Local Area Network

– Products?

• 1997: Wireless LAN

– IEEE 802.11

– 2.4 – 2.5 GHz and infrared, 2Mbit/s

– already many products (with proprietary extensions)

• 1998: Specification of GSM successors – GPRS is packet oriented

– UMTS is European proposal for IMT-2000

• 1998: Iridium – 66 satellites (+6 spare)

– 1.6GHz to the mobile phone


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Wireless systems: overview of the development

cellular phones satellites wireless LANcordless

phones

1992:

GSM

1994:

DCS 1800

2001:IMT-2000

1987:

CT1+

1982:

Inmarsat-A

1992:

Inmarsat-B

Inmarsat-M

1998:

Iridium

1989:

CT 2

1991:

DECT 199x:

proprietary

1997:

IEEE 802.11

1999:

802.11b, Bluetooth

1988:

Inmarsat-C

analogue

digital

1991:

D-AMPS

1991:

CDMA

1981:

NMT 450

1986:

NMT 900

1980:

CT0

1984:

CT1

1983:

AMPS

1993:PDC

2000:

GPRS2000:

IEEE 802.11a

200?:

Fourth Generation

(Internet based)


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The future: ITU-R - Recommendations for IMT-2000

• M.687-2 – IMT-2000 concepts and goals

• M.816-1

– framework for services

• M.817

– IMT-2000 network architectures

• M.818-1

– satellites in IMT-2000

• M.819-2

– IMT-2000 for developing countries

• M.1034-1 – requirements for the radio interface(s)

• M.1035

– framework for radio interface(s) and

radio sub-system functions

• M.1036 – spectrum considerations

• M.1078

– security in IMT-2000

• M.1079

– speech/voiceband data performance

• M.1167

– framework for satellites

• M.1168

– framework for management

• M.1223

– evaluation of security mechanisms

• M.1224

– vocabulary for IMT-2000

• M.1225

– evaluation of transmission technologies

• etc.

• www.itu.int/imt


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The success story of Mobile “Computing”

• Mobile Phones – Switzerland February 2002: More mobile phones than fixnet phones

– Worldwide: More mobile phones than Internet connections

– SMS: “More net profit with SMS than with voice”

• Laptops

– Switzerland 2001: For the first year less computers sold, but more mobile

computers; private households buy 18% more laptops than the previous year.

0

100

200

300

400

500

600

700800

1996 1997 `998 `999 2000 2001

Desktop

Mobile

[ R . W e

i s s ]


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Mobile phones worldwide

[ c r t . d k ]


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Mobile phones Top 12

[ c r t . d k ]


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Mobile phones saturation

[crt.dk]


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Internet vs. Mobile phones

[crt.dk]


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Simple reference model

Application

Transport

Network

Data Link

Physical

Medium

Data Link

Physical

Application

Transport

Network

Data Link

Physical

Data Link

Physical

Network Network

Radio

[ T a n e n b a u m / S c h i l l e r ]


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Course overview: Networking Bottom – Up Approach

– service location – new applications, multimedia

– adaptive applications

– congestion and flow control

– quality of service

– addressing, routing,

device location

– hand-over

– authentication

– media access

– multiplexing

– media access control

– encryption

– modulation

– interference – attenuation

– frequency

• Application layer

• Transport layer

• Network layer

• Data link layer

• Physical layer


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Course Overview: Acronyms

W S P / B

P D C

P O S

C C I R

B W U P T

B S S

M C C

F H S S

H I P E R L

A N I F S F I B

S N D C P

S - S A P

W W W

M S I S D

N L A I

P D A

A T I M

C W

D V B - T

I C M P

P S N

T T L

H E C G I F

L A P D

C S C W

I S O I T U L E D

C C H

C D M A

P A

I T U - R

P D N

I E E E

I r D A

A I D C S

C A C

H T M L

C C N D C

C C A

S N A C K

I M F

J P E G

H D T P

D P C H

H D B H O

G W L

C C X O R

T D - C D M A

J D C I S I

R T T

C T S

B C A

G T P

S I M

M M F

C E P T

S

C P A S - T P

S F D

U B R

D P C C H

S D M

P

T P - C L N S

R L U R I

P H S

T L L I

M O T

C U U I M P P P A I B

M N C

W R C

I M T - M C

W S P

W A P

A T M - C L

L B R

P M A

T C H / F

M - P N N I

H C S A P

E M A S

E I R P

C A T V

D N S

V + D F W

C S M A

D S L

F S K

P L L

A E S A

C S M A / C D

V C D H

H D L C T I

R A S M N S D P

D V T R

C O R B A

G E O

E D T V

H M Q o S

T C H / F S

H E O

P A D

H O - H M P D

U

S A P

S D M A

W M L

E H F

H I B F E C F I C

T C - H M P D

U

V D B

A I D A C T F R

P R A C H

A F S C I F L I

P A C S

R I P L o c

A G C H

A S A

I W F

B L I R

T R - S A P

U D P

S C F

I M T - F T

C n f

I S D N

H T T P

B P S K

T F O

E S S

R T T

T M N

M S R N

S N P D O

G M S C

S I G C N

H D T V

A U S T U S S D

C T S M S

D F W M A C

D H C P

B S C K I D

R O M

E T S I

I S M

Q P S K

U T R A

G R E T M R e q

D V B - S

F P L M T S

C C C H

I S L

M U L

D C

C O F D M

O S I

A M D V B

R T R

S E Q N

C O M S

R S S P S P M T O S P C D A B

P C S L S R S A

R R M C N T E I S

X M L

L F S S 7

M - N N I

H I

T - S A P

C O A

V C C

P T P C S P T M

W M L S c r i p t

M T S A

B L I R C S

R R I M S I

D A M A

R A N D

M I B

G M M

P C H R A N S S L I R S H S D T

B S S A P

S A A L

M A T M

W T L S

T I M F T J C T

P D T C H

G F S K

D - A M P S

C D M

P C M

C S D S W

U M T S

I V P S K

S T A R I B

E M A S - E

M S D U

T A R F C

C L M S

I R N M T

R L P

A C I D T I N A

D Q P S K

T F I

G P R S

P A C S - U

B

V H F P T A B R N S A

W C A C

N T S C

E Y - N P M

A

T M S I T D T

W D P C P U

H M P D U

S D U P L W

D V B - C H D A

C S M A / C

A

A C L

M O C

M A C A

D i s a s s o c

T D M L A N

D P D C H

P L M N D L C Q A M E I R A u C H I D R M D A

P L C P C M

S N A P L O S C A C

V N D C U H F

W C M P

L 2 C A P

A R I B M S K

E C D H

T E T R A

P H Y

D S D V

H A

T C H / H

A S C I I

S R E S

W T A

G S N

C R C

W 3 C

P A L

B R A N

P S T N

M E O

M C M

C K S N

C V S D

I - T C P

S U M R

H S C S D

L C R T

P O T S

H D A C S

T T C

A S K

F D M A

T - T C P

V B R - r t

L R U

B E R

D I F S

B S S

P P G

H D M L

E D G E

P R M A

M S C

N A - T D M A

B F S K

S D T V

T C P

G M S K

M S V P N

N A T

A M A

S C O

I M T - D S

H F

H

C P D U

U S I M

T

C H / H S

D S G P S

C G I

P L I

W I M

S

D C C H

N M A S

M C I

I M T - T C

C P M

O F D M

T I B

A N S I

B C C H

A S P

N F S

I T U - T

S F N

T F T S

W M T

M H E G

A T M N I B

R L C

W A N

S G S N

D E C T

P M D

W T A I

F C C H

F M

C A M E L

F A C O S

Q o S U E P I

T D D

S

C D M A

L M P

A R Q N

D C S

V L R

S A T M

V

B R - n r t

H M A C K

S w M I

F A C C H

D C C H

L A P D m

A K - H C P D

U

D T - H C P D

U

W L A N

S H F

V A D

S I F S

W L L R A M S C

P S F

W - C T R L

G P F D D

U W C

B S S G P

B C H M T I D

S M R I B

U T R A N

N N I

P I F S

G G S N

H C S D U

I M T

O M C

A A L

W T P

D C F

S C H

F C A

P D U I N

I M T - S C

S A

P S P D N

G E R A N

G S M

E D G E

R A N

M - U N I

D S R

T C H

M A C

R N S

B M P

O S S

W - C D M A

S C P S

A M E S I P

W A T M

S C A u t h

S E C - S A P

M F M S C B R

N R L

D S M A

D B P S K

3 G P P

H C

T D M A

M L

M T C

N A V A P

M - T C P

M B S

P T P - C O N

S

S C U D T S F

P D F

G S M

A D S L

U N I

L E O

M S A P

P I N

F D M

P C F

S S L

B T S M

I S M A

V L F

O T A

A D A

S A C C H

D S S S

R A C H

P U K

P P M

S A M A

M M

L A P C

I O T

P A D

R T S

R e s

I C O

D T I M

H B R C D T L S

V B R

D V D

M S I N

H C Q o S

L A D D I B

S S

P N N I

C I D R

D T M F

M S C E I T

I M E I

C o d e c

U P A R Q U N I L R

W A E

I E T F

C D V

A s s o c

H P D C A M H

C D P D

G A P

L L C B T S L M

B - I S D N

H L R

M - Q o S

T P C T V

W P A N

S I R A L G R

W P - C D M A

A M P S

N I T B L I

M P E G

V H E

P C S

C C F


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BluetoothSatellites

Optimal

Frequency

Allocation

Course overview: A large spectrum

TheorySystems

How can we

access a shared

channel?

WAP How does my

wireless LAN

card work?

How do I routein a mobile ad-

hoc network?

Orthogonal

codes

GSM

WML and

WMLscript

C i H d O E i


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Course overview: Hands-On Exercises

• We build a wireless LAN based ad-hoc network

– We start with the “hello world” equivalent

– Neighbor detection

– Chat application – Multihop routing

– Multihop project

– Emulator software

– Grading!

• Supported by

– paper exercises

C i L t d E i


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Course overview: Lectures and Exercises

Clustering

Mobile IP and TCP

[Ostern]

Mobile Web

GSM

[Pfingsten]

Topology Control

Geometric Routing

Ad-Hoc & Sensor Networks

Wireless LAN

Media Access Control

Physical and Link Layer

Introduction

Multihop Project 2

Instant Messenger

Multihop Project 3

Multihop Project 1

Theory: Ad-Hoc Networks

Multihop Routing 2 Multihop Routing 1

Topology Detection

Neighbor Detection

Theory: Codes/MAC

"Hello World"

Hard- and Software Tests

C i lti


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Course specialties

• Maximum possible spectrum of systems and theory

• New area, more open than closed questions

• Lecture and exercises are hard to synchronize

• http://distcomp.ethz.ch/mobicomp

Literature


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Literature

• Jochen Schiller – Mobile Communications / Mobilkommunikation

• Ivan Stojmeniovic – Handbook of Wireless Networks and Mobile

Computing

• Andrew Tanenbaum – Computer Networks, plus other books• Hermann Rohling – Einführung in die Informations– und

Codierungstheorie

• James D. Solomon – Mobile IP, the Internet unplugged

• Charles E. Perkins – Ad-hoc networking

• Plus tons of other books on specialized topics

• Papers, papers, papers, …

Famous last words


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Famous last words

“Mobile wireless computers are like

mobile pipeless bathrooms –

portapotties. They will be common on

vehicles, and at construction sites, and

rock concerts. My advice is to wire up

your home and stay there.”Bob Metcalfe, 1995

(Ethernet inventor)

chapter 1 introduction original

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