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CS647 - Advanced Topics in Wireless Networks

Introduction

Drs. Baruch Awerbuch & Amitabh MishraComputer Science Department

Johns Hopkins University

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A case for mobility – many aspectsHistory of mobile communicationMarketWireless Networks

Cellular NetworksAd hoc NetworksSensor Networks

Areas of research

Outline

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Computers for the next decades?

Computers are integratedsmall, cheap, portable, replaceable - no more separate devices

Technology is in the backgroundcomputer are aware of their environment and adapt (“location awareness”)computer recognize the location of the user and react appropriately (e.g., call forwarding, fax forwarding, “context awareness”))

Advances in technologymore computing power in smaller devicesflat, lightweight displays with low power consumptionnew user interfaces due to small dimensionsmore bandwidth per cubic metermultiple wireless interfaces: wireless LANs, wireless WANs, regional wireless telecommunication networks etc. (“overlay networks“)

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Mobile communication

Two aspects of mobility:user mobility: users communicate (wireless) “anytime, anywhere, with anyone”device portability: devices can be connected anytime, anywhere to the network

Wireless vs. mobile Examplesstationary computernotebook in a hotelwireless LANs in historic buildingsPersonal Digital Assistant (PDA)

The demand for mobile communication creates the need for integration of wireless networks into existing fixed networks:

local area networks: standardization of IEEE 802.11, ETSI (HIPERLAN)Internet: Mobile IP extension of the internet protocol IPwide area networks: e.g., internetworking of GSM and ISDN

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Cell (Mobile) Phone

As soon as the airplane’s door is opened, you can switch on the cell phone and you are connected….

Beacon Signals

Hello Message

Cellular Service Base Station

Cell Phone contacts the nearest Base Station and registers itself to get service

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Applications - Cellular

Maintaining the telephone number across geographical areas in a wireless and mobile system

Microwave Tower

Cell Chicago

Washington, DC

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First Generation Cellular Systems and Services

AMPS (Advanced Mobile Phone Service) introduced by AT&T in North America

1984

NMT (Nordic Mobile Telephone) 900 system introduced by Ericsson Radio System AB and deployed in Scandinavia

1981

NTT (Nippon Telephone & Telegraph) introduces the first cellular system in Japan

1979

WARC (World Administrative Radio Conference) allocates spectrum for cellular radio

1976

Developments of radio and computer technologies for 800/900 MHz mobile communications

1970s

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Second Generation Cellular Systems and Services

IS-54: North AmericaIS-95: North America, Hong Kong, Israel, Japan, China, etcGSM: 110 countries

1999North American PCS deploys GSM, IS-54, IS-951997Phase II GSM operational1996PCS Licenses issued in North America1995Interim Standard IS-136 adopted by TIA1994Interim Standard IS-95 (CDMA) adopted by TIA1993Phase I GSM system is operational1992

Japanese PDC (Personal Digital Cellular) system standardized by the MPT (Ministry of Posts and Telecommunications)

1991Interim Standard IS-19B (NAMPS) adopted by TIA1990

Interim Standard IS-54 (USDC) adopted by TIA (Telecommunications Industry Association)

1990

CEPT (Conference Europeenne des Post et Telecommunications) established GSM to define future Pan-European cellular Radio Standards

1982

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Worldwide wireless subscribers (old prediction 1998)

0

100

200

300

400

500

600

700

1996 1997 1998 1999 2000 2001

AmericasEuropeJapanotherstotal

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Mobile phones per 100 people 1999

0 10 20 30 40 50 60

FinlandSwedenNorway

DenmarkItaly

LuxemburgPortugal

AustriaIreland

SwitzerlandGreat BritainNetherlands

FranceBelgium

SpainGreece

Germany

2005: 70-90% penetration in Western Europe

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Worldwide cellular subscriber growth

0

200

400

600

800

1000

1200

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Sub

scri

bers

[mill

ion]

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

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Third Generation Cellular Systems and Services (1/2)

IMT-2000 (International Mobile Telecommunications-2000):- Fulfill one's dream of anywhere, anytime communications a reality.

Key Features of IMT-2000 include:- High degree of commonality of design worldwide; - Compatibility of services within IMT-2000 and with the fixed networks;

- High quality; - Small terminal for worldwide use; - Worldwide roaming capability; - Capability for multimedia applications, and a wide

range of services and terminals.

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Third Generation Cellular Systems and Services (2/2)

Important Component of IMT-2000 is its ability to provide high bearer rate capabilities:

- 2 Mbps for fixed environment;- 384 Kbps for indoor/outdoor and pedestrian

environment;- 144 kbps for vehicular environment.

Standardization Work:- In progress

Scheduled Service:- Started in October 2001 in Japan (W-CDMA)

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Foundation: ITU-R - Recommendations for IMT-2000

M.687-2IMT-2000 concepts and goals

M.816-1framework for services

M.817IMT-2000 network architectures

M.818-1satellites in IMT-2000

M.819-2IMT-2000 for developing countries

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

M.1035framework for radio interface(s) and radio sub-system functions

M.1036spectrum considerations

M.1078security in IMT-2000

M.1079speech/voiceband data performance

M.1167framework for satellites

M.1168framework for management

M.1223evaluation of security mechanisms

M.1224vocabulary for IMT-2000

M.1225evaluation of transmission technologies

. . .

http://www.itu.int/imt

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Macrocell

Suburban

Coverage Aspect of Next Generation Mobile Communication Systems

Microcell

Urban

Satellite

Global

Global

Picocell

In-building

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Transmission Capacity

Broadband radio

Glo

bal S

yste

mfo

r Mob

ile C

omm

unic

atio

ns

0.01 0.1 1 10 100

Transmission capacity as a function of mobility in some radio access systems

Mob

ility

Universal Mobile Telecommunications System

Mobile Broadband System

Broadband Satellite Multimedia

Local Multipoint Distribution System

Satellite Universal Mobile Telecommunications System

Data rate (Mb/s)

Stationary

Pedestrian

Vehicular

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Medical and Healthcare Applications

ATM Backbone Network

ATM Backbone Network

Possibility for Remote consulting (including Audio Visual communication)

ATM Switch

Wireless Remote consultation from Ambulance

ATM Switch

Remote Databases

In HospitalPhysician

Sensors on body

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Applications I

Vehiclestransmission of news, road condition, weather, music via DABpersonal communication using GSMposition via GPSlocal ad-hoc network with vehicles close-by to prevent accidents, guidance system, redundancy vehicle data (e.g., from busses, high-speed trains) can be transmitted in advance for maintenance

Emergenciesearly transmission of patient data to the hospital, current status, first diagnosisreplacement of a fixed infrastructure in case of earthquakes, hurricanes, fire etc.crisis, war, ...

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Typical application: road traffic

ad ho

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

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

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Mobile and wireless services – Always 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

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Applications II

Travelling salesmendirect access to customer files stored in a central locationconsistent databases for all agentsmobile office

Replacement of fixed networksremote sensors, e.g., weather, earth activitiesflexibility for trade showsLANs in historic buildings

Entertainment, education, ...outdoor Internet access intelligent travel guide with up-to-datelocation dependent informationad-hoc networks formulti user games

HistoryInfo

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Location dependent services

Location aware serviceswhat services, e.g., printer, fax, phone, server etc. exist in the local environment

Follow-on servicesautomatic call-forwarding, transmission of the actual workspace to the current location

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

Support servicescaches, intermediate results, state information etc. „follow“ the mobile device through the fixed network

Privacywho should gain knowledge about the location

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Mobile 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

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Effects of device portability

Power consumptionlimited computing power, low quality displays, small disks due to limited battery capacityCPU: power consumption ~ CV2f

C: internal capacity, reduced by integrationV: supply voltage, can be reduced to a certain limitf: clock frequency, can be reduced temporally

Loss of datahigher probability, has to be included in advance into the design (e.g., defects, theft)

Limited user interfacescompromise between size of fingers and portabilityintegration of character/voice recognition, abstract symbols

Limited memorylimited value of mass memories with moving partsflash-memory or ? as alternative

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Wireless networks in comparison to fixed networks

Higher loss-rates due to interferenceemissions of, e.g., engines, lightning

Restrictive regulations of frequenciesfrequencies have to be coordinated, useful frequencies are almost all occupied

Low transmission rateslocal some Mbit/s, regional currently, e.g., 53kbit/s with GSM/GPRS

Higher delays, higher jitterconnection setup time with GSM in the second range, several hundred milliseconds for other wireless systems

Lower security, simpler active attackingradio interface accessible for everyone, base station can be simulated, thus attracting calls from mobile phones

Always shared mediumsecure access mechanisms important

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Early history of wireless communication

Many people in history used light for communicationheliographs, flags („semaphore“), ...150 BC smoke signals for communication;(Polybius, Greece)1794, optical telegraph, Claude Chappe

Here electromagnetic waves are of special importance:

1831 Faraday demonstrates electromagnetic inductionJ. Maxwell (1831-79): theory of electromagnetic Fields, wave equations (1864)H. Hertz (1857-94): demonstrateswith an experiment the wave character of electrical transmission through space(1888, in Karlsruhe, Germany, at the location of today’s University of Karlsruhe)

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History of wireless communication I

1896Guglielmo Marconifirst demonstration of wireless telegraphy (digital!)long wave transmission, high transmission power necessary (> 200kw)

1907Commercial transatlantic connectionshuge base stations (30 100m high antennas)

1915Wireless voice transmission New York - San Francisco1920Discovery of short waves by Marconi

reflection at the ionospheresmaller sender and receiver, possible due to the invention of the vacuum tube (1906, Lee DeForest and Robert von Lieben)

1926Train-phone on the line Hamburg - Berlinwires parallel to the railroad track

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History of wireless communication II

1928 many TV broadcast trials (across Atlantic, color TV, TV news)1933 Frequency modulation (E. H. Armstrong)1958A-Netz in Germany

analog, 160MHz, connection setup only from the mobile station, no handover, 80% coverage, 1971 11000 customers

1972B-Netz in Germanyanalog, 160MHz, connection setup from the fixed network too (butlocation of the mobile station has to be known)available also in Austria, Netherland and Luxembourg, 1979 13000 customer in D

1979NMT at 450MHz (Scandinavian countries)1982Start of GSM-specification

goal: pan-European digital mobile phone system with roaming1983Start of the American AMPS (Advanced Mobile Phone

System, analog) 1984CT-1 standard (Europe) for cordless telephones

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History of wireless communication III

1986C-Netz in Germanyanalog voice transmission, 450MHz, hand-over possible, digital signaling, automatic location of mobile deviceWas in use until 2000, services: FAX, modem, X.25, e-mail, 98% coverage

1991Specification of DECTDigital European Cordless Telephone (today: Digital Enhanced Cordless Telecommunications)1880-1900MHz, ~100-500m range, 120 duplex channels, 1.2Mbit/s data transmission, voice encryption, authentication, up to several 10000 user/km2, used in more than 50 countries

1992Start of GSMin D as D1 and D2, fully digital, 900MHz, 124 channelsautomatic location, hand-over, cellularroaming in Europe - now worldwide in more than 200 countriesservices: data with 9.6kbit/s, FAX, voice, ...

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History of wireless communication IV

1994E-Netz in GermanyGSM with 1800MHz, smaller cellsAs Eplus in D (1997 98% coverage of the population)

1996HiperLAN (High Performance Radio Local Area Network)ETSI, standardization of type 1: 5.15 - 5.30GHz, 23.5Mbit/srecommendations for type 2 and 3 (both 5GHz) and 4 (17GHz) as wireless ATM-networks (up to 155Mbit/s)

1997Wireless LAN - IEEE802.11IEEE standard, 2.4 - 2.5GHz and infrared, 2Mbit/salready many (proprietary) products available in the beginning

1998Specification of GSM successorsfor UMTS (Universal Mobile Telecommunication System) as Europeanproposals for IMT-2000

Iridium66 satellites (+6 spare), 1.6GHz to the mobile phone

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History of wireless communication V

1999 Standardization of additional wireless LANsIEEE standard 802.11b, 2.4-2.5GHz, 11Mbit/sBluetooth for piconets, 2.4Ghz, <1Mbit/s

Decision about IMT-2000Several “members” of a “family”: UMTS, cdma2000, DECT, …

Start of WAP (Wireless Application Protocol) and i-modeFirst step towards a unified Internet/mobile communicaiton systemAccess to many services via the mobile phone

2000 GSM with higher data ratesHSCSD offers up to 57,6kbit/sFirst GPRS trials with up to 50 kbit/s (packet oriented!)

UMTS auctions/beauty contestsHype followed by disillusionment (50 B$ payed in Germany for 6 licenses!)

2001 Start of 3G systemsCdma2000 in Korea, UMTS tests in Europe, Foma (almost UMTS) in Japan

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Wireless systems: overview of the development

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)

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Cellular subscribers per 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

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Mobile statistics snapshot (09/2002 / 12/2004)

Total Global Mobile Users869M / 1.52bn

Total Analogue Users 71M / 34mTotal US Mobile users 145M / 140mTotal Global GSM users 680M / 1.25TTotal Global CDMA Users 127M / 202mTotal TDMA users 84M / 120mTotal European users 283M / 343mTotal African users 18.5M / 53mTotal 3G users 130M / 130m(?)Total South African users 13.2m / 19mEuropean Prepaid Penetration 63% European Mobile Penetration 70.2% Global Phone Shipments 2001 393m Global Phone Sales 2Q02 96.7m

http://www.cellular.co.za/stats/stats-main.htm

#1 Mobile Country China (139M / 300m) #1 GSM Country China (99m) #1 SMS Country Philipines#1 Handset Vendor 2Q02 Nokia (37.2%) #1 Network In Africa Vodacom (6.6m) #1 Network In Asia Unicom (153m)#1 Network In Japan DoCoMo#1 Network In Europe T-Mobile (22m /

28m) #1 In Infrastructure Ericsson SMS Sent Globally 1Q02 60T / 135bnSMS sent in UK 6/02 1.3T / 2.1bnSMS sent Germany 1Q02 5.7T GSM Countries on Air 171 / 210GSM Association members 574 / 839Total Cost of 3G Licenses in Europe

110T€ SMS/month/user 36

The figures vary a lot depending on the statistic, creator of the statistic etc.!

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Simple reference model used here

Application

Transport

Network

Data Link

Physical

Medium

Data Link

Physical

Application

Transport

Network

Data Link

Physical

Data Link

Physical

Network Network

Radio

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Influence of mobile communication to the layer model

service locationnew applications, multimediaadaptive applicationscongestion and flow controlquality of serviceaddressing, routing, device locationhand-overauthenticationmedia accessmultiplexingmedia access controlencryptionmodulationinterferenceattenuationfrequency

Application layer

Transport layer

Network layer

Data link layer

Physical layer

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Scope of Wireless technologies

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The envisioned communication puzzle of beyond 4G

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Overlay Networks - the global goal

regional

metropolitan area

campus-based

in-house

verticalhandover

horizontalhandover

integration of heterogeneous fixed andmobile networks with varyingtransmission characteristics

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Areas of research in mobile communication

Wireless Communicationtransmission quality (bandwidth, error rate, delay)modulation, coding, interferencemedia access, regulations...

Mobilitylocation dependent serviceslocation transparencyquality of service support (delay, jitter, security)Routing...

Portabilitypower consumptionlimited computing power, sizes of display, ...usability

Security..