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Mobile Communication WS 2005/
Chair for Computer Networks & Internet Wilhelm-Schickard-Institute for Computer Science University of Tübingen
Mobile Communications
Prof. Dr.-Ing. Georg Carle Dipl.-Ing. Christian Hoene
Chair for Computer Networks & Internet Wilhelm-Schickard-Institute for Computer Science University of Tübingen
http://net.informatik.uni-tuebingen.de/ carle|[email protected]
Winter Term 2005/
Mobile Communication WS 2005/06 2.
Acknowledgements
This course, including the slides, is based on the course on mobile
communications of my former colleague,
Prof. Dr.-Ing. Jochen Schiller , Free University Berlin, author of the book
"Mobile Communications" , published by Addison-Wesley.
In case of questions, suggestions or comments to the course material
Mobile Communication WS 2005/06 2.
Course organization
Lecture Thursday 15.00-17.00, Sand 1, A Übung (14-tägig): Wednesday 15-17 Uhr (Auf der Morgenstelle - Gebäude C - 9. Stock - A03)
Questions and Answers / Office hours Prof. Dr. Georg Carle
- After the course
- Office hours: Thursday, 11.00 to 12.00, Auf der Morgenstelle 10C Dipl.-Ing. Christian Hoene
- [email protected]; Auf der Morgenstelle 10C9, Tel. 07071-29- Dipl.-Inf. Andreas Klenk
- [email protected]; Auf der Morgenstelle 10C9, Tel. 07071-29-
News and updates http://net.informatik.uni-tuebingen.de/
Literature All slides are available online (and without the slides it is very difficult to follow the lectures...)! The slides may be updated during the course. This course is based on the book "Mobile Communications”, 2nd edition, by Jochen Schiller , available in English, German, Chinese, and Finnish.
Mobile Communication WS 2005/06 2.
Georg Carle
1985-1992: Study of Electrical Engineering, University of Stuttgart Master of Science in Digital Systems, Brunel University, London, U.K. (Master Thesis at General Electric Corporation, Hirst Research Centre, London) Research project at Telecom Paris - Ecole Nationale Supérieure des Télécommunications (ENST), Paris Sept. 1992 - Dec. 1996: Doctoral Degree in Computer Science at University of Karlsruhe in 1996, working as Scientist at Institute of Telematics and Member of Graduiertenkolleg 'Controllability of Complex Systems' Jan.-Oct. 1997: Postdoctoral Researcher, Institut Eurecom, Sophia Antipolis, France Oct. 1997-Dec. 2002: Fraunhofer Institut FOKUS (previously: GMD FOKUS): Head of Competence Center Global Networking Since Dec. 2002: Chair for Computer Networks and Internet, University of Tübingen
Mobile Communication WS 2005/06 2.
Computers for the next decades?
Computers are integrated
small, cheap, portable, replaceable - no more separate devices
Technology is in the background
computer 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”)) this and related functionality is summarized under “ambient intelligence”
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 cubic meter multiple wireless interfaces: wireless LANs, wireless WANs, regional wireless telecommunication networks etc. („overlay networks“)
Mobile Communication WS 2005/06 2.
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 Examples
8 8 stationary computer 8 9 notebook in a hotel 9 8 wireless LANs in historic buildings 9 9 Personal 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 IP wide area networks: e.g., internetworking of GSM and ISDN
Mobile Communication WS 2005/06 2.
Applications I
Vehicles
transmission of news, road condition, weather, music via DAB personal communication using GSM position via GPS local 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
Emergencies
early transmission of patient data to the hospital, current status, first diagnosis replacement of a fixed infrastructure in case of earthquakes, hurricanes, fire etc. crisis, war, ...
Mobile Communication WS 2005/06 2.
Typical application: road traffic
ad hoc
UMTS, WLAN,
DAB, GSM,
cdma2000, TETRA, ...
Personal Travel Assistant, PDA, Laptop, GSM, UMTS, WLAN, Bluetooth, ...
Mobile Communication WS 2005/06 2.
Location dependent services
Location aware services
what services, e.g., printer, fax, phone, server etc. exist in the local environment
Follow-on services
automatic 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 services
caches, intermediate results, state information etc. „follow“ the mobile device through the fixed network
Privacy
who should gain knowledge about the location
Mobile Communication WS 2005/06 2.
Mobile devices
performanceperformance
Pager
- receive only
- tiny displays
- simple text messages
Mobile phones
- voice, data
- simple graphical displays
PDA
- simpler graphical displays
- character recognition
- simplified WWW
Palmtop
- tiny keyboard
- simple versions of standard applications
Laptop/Notebook
- fully functional
- standard applications
Sensors, embedded controllers
www.scatterweb.net
Mobile Communication WS 2005/06 2.
Effects of device portability
Power consumption
limited computing power, low quality displays, small disks due to limited battery capacity CPU: power consumption ~ CV 2 f
- C: internal capacity, reduced by integration
- V: supply voltage, can be reduced to a certain limit
- f: clock frequency, can be reduced temporally
Loss of data
higher probability, has to be included in advance into the design (e.g., defects, theft)
Limited user interfaces
compromise between size of fingers and portability integration of character/voice recognition, abstract symbols
Limited memory
limited value of mass memories with moving parts flash-memory or harddisc as alternative
Mobile Communication WS 2005/06 2.
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.,53kbit/s with GSM/GPRS
Higher delays, higher jitter
connection setup time with GSM in the second range, several hundred milliseconds for other wireless systems
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
Mobile Communication WS 2005/06 2.
History of wireless communication II
1928 many TV broadcast trials (across Atlantic, color TV, TV news)
1933 Frequency modulation (E. H. Armstrong)
1958 “A-Netz” in Germany
analog, 160MHz, connection setup only from the mobile station, no handover, 80% coverage, 1971 11000 customers
1972 “B-Netz” in Germany
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
1979 NMT at 450MHz (Scandinavian countries)
1982 Start of GSM-specification
goal: pan-European digital mobile phone system with roaming
1983 Start of the American AMPS (Advanced Mobile Phone
System, analog)
1984 CT-1 standard (Europe) for cordless telephones
Mobile Communication WS 2005/06 2.
History of wireless communication III
1986 “C-Netz” in Germany
analog voice transmission, 450MHz, hand-over possible, digital signaling, automatic location of mobile device Was in use until 2000, services: FAX, modem, X.25, e-mail, 98% coverage
1991 Specification of DECT
Digital 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/km 2 , used in more than 50 countries
1992 Start of GSM
in D as D1 and D2, fully digital, 900MHz, 124 channels automatic location, hand-over, cellular roaming in Europe - now worldwide in more than 200 countries services: data with 9.6kbit/s, FAX, voice, ...
Mobile Communication WS 2005/06 2.
History of wireless communication IV
1994 E-Netz in Germany
GSM with 1800MHz, smaller cells As Eplus in D (1997 98% coverage of the population )
1996 HiperLAN (High Performance Radio Local Area Network)
ETSI, standardization of type 1: 5.15 - 5.30GHz, 23.5Mbit/s recommendations for type 2 and 3 (both 5GHz) and 4 (17GHz) as wireless ATM-networks (up to 155Mbit/s)
1997 Wireless LAN - IEEE802.
IEEE standard, 2.4 - 2.5GHz and infrared, 2Mbit/s already many (proprietary) products available in the beginning
1998 Specification of GSM successors
for UMTS (Universal Mobile Telecommunication System) as European proposals for IMT-
Iridium
66 satellites (+6 spare), 1.6GHz to the mobile phone
Mobile Communication WS 2005/06 2.
History of wireless communication V
1999 Standardization of additional wireless LANs
IEEE standard 802.11b, 2.4-2.5GHz, 11Mbit/s Bluetooth for piconets, 2.4Ghz, <1Mbit/s
Decision about IMT-
Several “members” of a “family”: UMTS, cdma2000, DECT, …
Start of WAP (Wireless Application Protocol) and i-mode
First step towards a unified Internet/mobile communicaiton system Access to many services via the mobile phone
2000 GSM with higher data rates
HSCSD offers up to 57,6kbit/s First GPRS trials with up to 50 kbit/s (packet oriented!)
UMTS auctions/beauty contests
Hype followed by disillusionment (approx. 50 B$ payed in Germany for 6 UMTS licenses !)
2001 Start of 3G systems
Cdma2000 in Korea, UMTS in Europe, Foma (almost UMTS) in Japan
Mobile Communication WS 2005/06 2.
Worldwide wireless subscribers (old prediction 1998)
Americas Europe Japan others total
Mobile Communication WS 2005/06 2.
Mobile phones per 100 people 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
2002: 50-70% penetration in Western Europe
Mobile Communication WS 2005/06 2.
Worldwide cellular subscriber growth
0
200
400
600
800
1000
1200
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Subscribers [million]
Note that the curve starts to flatten in 2000
Mobile Communication WS 2005/06 2.
Cellular subscribers per region (June 2002)
Asia Pacific; 36,
Europe; 36,
Americas (incl. USA/Canada); 22
Africa; 3,
Middle East; 1,
Mobile Communication WS 2005/06 2.
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
Mobile Communication WS 2005/06 2.
Influence of mobile communication to the layer model
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
Mobile Communication WS 2005/06 2.
Overview of the main chapters
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
Mobile Communication WS 2005/06 2.
Overlay Networks - the global goal
regional
metropolitan area
campus-based
in-house
vertical handover
horizontal handover
integration of heterogeneous fixed and mobile networks with varying transmission characteristics
