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CS 647 1.1
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..
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