Mobile Mobile CommunicationCommunication

ss

IntroductionIntroduction

A case for mobility – many aspectsA case for mobility – many aspects History of mobile communicationHistory of mobile communication MarketMarket Areas of researchAreas of research

Mobile communicationMobile communication Two aspects of mobility:Two aspects of mobility:

user mobilityuser mobility: users communicate (wireless) “anytime, : users communicate (wireless) “anytime, anywhere, with anyone”anywhere, with anyone”

device portabilitydevice portability: devices can be connected anytime, : devices can be connected anytime, anywhere to the networkanywhere to the network

Wireless vs. mobile ExamplesWireless vs. mobile Examples stationary computerstationary computer notebook in a hotelnotebook in a hotel wireless LANs in historic buildingswireless LANs in historic buildings Personal Digital Assistant (PDA)Personal Digital Assistant (PDA)

The demand for mobile communication creates the need for The demand for mobile communication creates the need for integration of wireless networks into existing fixed networks:integration of wireless networks into existing fixed networks: local area networks: standardization of IEEE 802.11, local area networks: standardization of IEEE 802.11,

ETSI (HIPERLAN)ETSI (HIPERLAN) Internet: Mobile IP extension of the internet protocol IPInternet: Mobile IP extension of the internet protocol IP wide area networks: e.g., internetworking of GSM and ISDNwide area networks: e.g., internetworking of GSM and ISDN

Applications Applications

VehiclesVehiclestransmission of news, road condition, weather, music via DABtransmission of news, road condition, weather, music via DABpersonal communication using GSMpersonal communication using GSMposition via GPSposition via GPSlocal ad-hoc network with vehicles close-by to prevent accidents, local ad-hoc network with vehicles close-by to prevent accidents,

guidance system, redundancy guidance system, redundancy vehicle data (e.g., from busses, high-speed trains) can be transmitted vehicle data (e.g., from busses, high-speed trains) can be transmitted

in advance for maintenance in advance for maintenance

EmergenciesEmergenciesearly transmission of patient data to the hospital, current status, first early transmission of patient data to the hospital, current status, first

diagnosisdiagnosisreplacement of a fixed infrastructure in case of earthquakes, replacement of a fixed infrastructure in case of earthquakes,

hurricanes, fire etc.hurricanes, fire etc.crisis, war, ...crisis, war, ...

Typical application: road Typical application: road traffictraffic

ad ho

cUMTS, WLAN,DAB, DVB, GSM, cdma2000, TETRA, ...

Personal Travel Assistant,PDA, Laptop, GSM, UMTS, WLAN, Bluetooth, ...

Mobile and wireless services – Mobile and wireless services – Always Best ConnectedAlways Best Connected

UMTS2 Mbit/s

UMTS, GSM384 kbit/s

LAN100 Mbit/s,WLAN54 Mbit/s

UMTS, GSM115 kbit/s

GSM 115 kbit/s,WLAN 11 Mbit/s

GSM/GPRS 53 kbit/sBluetooth 500 kbit/s

GSM/EDGE 384 kbit/s,DSL/WLAN 3 Mbit/s

DSL/ WLAN3 Mbit/s

Applications Applications Travelling salesmenTravelling salesmen

direct access to customer files stored in a central locationdirect access to customer files stored in a central location consistent databases for all agentsconsistent databases for all agents mobile officemobile office

Replacement of fixed networksReplacement of fixed networks remote sensors, e.g., weather, earth activitiesremote sensors, e.g., weather, earth activities flexibility for trade showsflexibility for trade shows LANs in historic buildingsLANs in historic buildings

Entertainment, education, ...Entertainment, education, ... outdoor Internet access outdoor Internet access intelligent travel guide with up-to-dateintelligent travel guide with up-to-date

location dependent informationlocation dependent information ad-hoc networks forad-hoc networks for

multi user games multi user games

HistoryInfo

Location dependent servicesLocation dependent services Location aware servicesLocation aware services

what services, e.g., printer, fax, phone, server etc. exist in what services, e.g., printer, fax, phone, server etc. exist in the local environmentthe local environment

Follow-on servicesFollow-on services automatic call-forwarding, transmission of the actual automatic call-forwarding, transmission of the actual

workspace to the current locationworkspace to the current location Information servicesInformation services

„„push“: e.g., current special offers in the supermarketpush“: e.g., current special offers in the supermarket „„pull“: e.g., where is the Black Forrest Cherry Cake?pull“: e.g., where is the Black Forrest Cherry Cake?

Support servicesSupport services caches, intermediate results, state information etc. „follow“ caches, intermediate results, state information etc. „follow“

the mobile device through the fixed networkthe mobile device through the fixed network PrivacyPrivacy

who should gain knowledge about the locationwho should gain knowledge about the location

Mobile devicesMobile devices

performanceperformance

Pager• receive only• tiny displays• simple text messages

Mobile phones• voice, data• simple graphical displays

PDA• graphical displays• character recognition• simplified WWW

Palmtop• tiny keyboard• simple versions of standard applications

Laptop/Notebook• fully functional• standard applications

Sensors,embeddedcontrollers

www.scatterweb.net

Effects of device portabilityEffects of device portability Power consumptionPower consumption

limited computing power, low quality displays, small disks limited computing power, low quality displays, small disks due to limited battery capacitydue to limited battery capacity

CPU: CPU: power consumption ~ CVpower consumption ~ CV22ff C: internal capacity, reduced by integrationC: internal capacity, reduced by integration V: supply voltage, can be reduced to a certain limitV: supply voltage, can be reduced to a certain limit f: clock frequency, can be reduced temporallyf: clock frequency, can be reduced temporally

Loss of dataLoss of data higher probability, has to be included in advance into the higher probability, has to be included in advance into the

design (e.g., defects, theft)design (e.g., defects, theft) Limited user interfacesLimited user interfaces

compromise between size of fingers and portabilitycompromise between size of fingers and portability integration of character/voice recognition, abstract symbolsintegration of character/voice recognition, abstract symbols

Limited memoryLimited memory limited value of mass memories with moving partslimited value of mass memories with moving parts flash-memory or ? as alternativeflash-memory or ? as alternative

Wireless networks in Wireless networks in comparison to fixed networkscomparison to fixed networks

Restrictive regulations of frequenciesRestrictive regulations of frequencies frequencies have to be coordinated, useful frequencies are almost frequencies have to be coordinated, useful frequencies are almost

all occupiedall occupied Low transmission ratesLow transmission rates

local some Mbit/s, regional currently, e.g., 53kbit/s with GSM/GPRSlocal some Mbit/s, regional currently, e.g., 53kbit/s with GSM/GPRS Higher delays, higher jitterHigher delays, higher jitter

connection setup time with GSM in the second range, several connection setup time with GSM in the second range, several hundred milliseconds for other wireless systemshundred milliseconds for other wireless systems

Higher loss-rates due to interferenceHigher loss-rates due to interference emissions of, e.g., engines, lightningemissions of, e.g., engines, lightning

Lower security, simpler active attackingLower security, simpler active attacking radio interface accessible for everyone, base station can be radio interface accessible for everyone, base station can be

simulated, thus attracting calls from mobile phonessimulated, thus attracting calls from mobile phones Always shared mediumAlways shared medium

secure access mechanisms importantsecure access mechanisms important

Wireless systems: overview of the Wireless systems: overview of the developmentdevelopment

cellular phones satellites wireless LANcordlessphones

1992:GSM

1994:DCS 1800

2001:IMT-2000

1987:CT1+

1982:Inmarsat-A

1992:Inmarsat-BInmarsat-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

4G – fourth generation: when and how?

2000:GPRS

2000:IEEE 802.11a

200?:Fourth Generation(Internet based)

Mobile phones per 100 Mobile phones per 100 people 1999people 1999

0 10 20 30 40 50 60

Finland

Sweden

Norway

Denmark

Italy

Luxemburg

Portugal

Austria

Ireland

Switzerland

Great Britain

Netherlands

France

Belgium

Spain

Greece

Germany

2005: 70-90% penetration in Western Europe

Worldwide cellular subscriber Worldwide cellular subscriber growthgrowth

0

200

400

600

800

1000

1200

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Su

bsc

rib

ers

[mil

lio

n]

Note that the curve starts to flatten in 2000 – 2004: 1.5 billion users

Cellular subscribers per Cellular subscribers per region (June 2002)region (June 2002)

Asia Pacific; 36,9

Europe; 36,4

Americas (incl. USA/Canada);

22

Africa; 3,1

Middle East; 1,6

2004: 715 million mobile phones delivered

Areas of research in mobile Areas of research in mobile communicationcommunication

Wireless CommunicationWireless Communication transmission quality (bandwidth, error rate, delay)transmission quality (bandwidth, error rate, delay) modulation, coding, interferencemodulation, coding, interference media access, regulationsmedia access, regulations

MobilityMobility location dependent serviceslocation dependent services location transparencylocation transparency quality of service support (delay, jitter, security)quality of service support (delay, jitter, security)

PortabilityPortability power consumptionpower consumption limited computing power, sizes of display, ...limited computing power, sizes of display, ... usabilityusability ......

Simple reference model used Simple reference model used herehere

Application

Transport

Network

Data Link

Physical

Medium

Data Link

Physical

Application

Transport

Network

Data Link

Physical

Data Link

Physical

Network Network

Radio

Influence of mobile Influence of mobile communication to the layer communication to the layer

modelmodelservice locationservice locationnew applications, multimedianew applications, multimediaadaptive applicationsadaptive applicationscongestion and flow controlcongestion and flow controlquality of servicequality of serviceaddressing, routing, addressing, routing,

device locationdevice locationhand-overhand-overauthenticationauthenticationmedia accessmedia accessmultiplexingmultiplexingmedia access controlmedia access controlencryptionencryptionmodulationmodulationinterferenceinterferenceattenuationattenuationfrequencyfrequency

Application layerApplication layer

Transport layerTransport layer

Network layerNetwork layer

Data link layerData link layer

Physical layerPhysical layer

Overview of the main Overview of the main chapterschapters

Chapter 2: Wireless Transmission

Chapter 3: Medium Access Control

Chapter 4: Telecommunication

Systems

Chapter 5: Satellite Systems

Chapter 6: Broadcast Systems

Chapter 7: Wireless

LAN

Chapter 8: Mobile Network Layer

Chapter 9: Mobile Transport Layer

Chapter 10: Support for Mobility

Overlay Networks - the global goalOverlay Networks - the global goal

regional

metropolitan area

campus-based

in-house

verticalhandover

horizontalhandover

integration of heterogeneous fixed andmobile networks with varyingtransmission characteristics