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REDES INALÁMBRICAS Máster de Ingeniería de Computadores-DISCA
Redes Inalámbricas – Tema 1 General conceptsRedes Inalámbricas – Tema 1 General concepts
An overall view of: Technologies MANETs networks Applications Devices References
Acknowledgments Mark Weiser Vint Cerf Jim Kurose, Keith Ross, “Computer Networking: A Top Down Approach Featuring the Internet,
2nd edition. Addison-Wesley, July 2002
REDES INALÁMBRICAS Máster de Ingeniería de Computadores-DISCA
Redes Inalámbricas – Tema 1 General conceptsRedes Inalámbricas – Tema 1 General concepts
Technologies
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2010 Various types of wireless technologies
WiMax WiFi Bluetooth Network telephony. Various
generations: GSM GPRS, EDGE; UMTS HSDPA LTE
Satellites: Satellites Geostationary Earth Orbit
(GEO) Example: Inmarsat
Satellites Low-Earth Orbit (LEO) Example : Iridium (66 satellites)
(2.4 Kbps data)
Infrared: IrDA Ultra-Wide Band (UWB) RFID Zigbee …
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Wireless networks are the best option for mobile devices: Easy installation: no problems with cables Systems easily expandable according to the needs
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Local AreaLocal AreaPersonal AreaPersonal Area Wide AreaWide Area
Wireless LAN
IEEE 802.11
PAN
Bluetooth
Cellular Systems
GSM, GPRS, EDGE
UMTS
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2010 Uses of WLANs
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• COMMON AREAS,• MEETING ROOMS,• LABORATORIES,
• TEMPORARY OFFICE
“CORPORATE CAMPUS”
• AIRPORTS• HOTELS
• CONVENTION CENTER
“HOME OFFICE”
“HOT SPOTS”
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DSC
HDTV
STB/Media Center
PC
Photo/Printer
Mobile/Smart HH
Mass Storage
Substitute cables
Personal ad hoc connectivity
KB, Mouse
DVC
Voice, Stereo Audio
BT Model UWB Model
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There are several types of mobility Physical mobility (of the devices)
off line connectivity: portable on line connectivity : mobile
Logical mobility: Of the processes Of the applications “ubiquitous computing”
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Bandwidth variability Applications should adapt. E.g., a videoconferencing application could
vary the image size or its quality when varying the bandwidth. Disconnection
Allow asynchronous operations, pre-fetching, caching, weak consistency, ...
Security and privacy The wireless channels are prone to "wiretapping''(snooping) Who should be given access to the location information? How much
accurate should be this information? Energy management:
stop discs, turn off the screen, standby mode of the CPU, put to sleep the network card, …
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“Mobile ad hoc networking: imperatives and challenges”, Imrich Chlamtac, Marco Conti, Jennifer J.-N. Liu, Ad Hoc Networks, Elsevier, 1 (2003).
REDES INALÁMBRICAS Máster de Ingeniería de Computadores-DISCA
Redes Inalámbricas – Tema 1 General conceptsRedes Inalámbricas – Tema 1 General concepts
Devices
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Mica Hardware Platform: The Mica sensor node (left) with the Mica Weather Board developed for environmental monitoring applications
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World’s smallest web serverhttp://www.webservusb.com/
IP picture framehttp://www.ceiva.com/
Web-enabled toaster+weather forecaster
Screenfridge
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REDES INALÁMBRICAS Máster de Ingeniería de Computadores-DISCA
Redes Inalámbricas – Tema 1 General conceptsRedes Inalámbricas – Tema 1 General concepts
MANETs networks
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Networks formed by mobile wireless nodes. Do not use any existing infrastructure
There are hybrid solutions known as "mesh networks“
In a MANET mobility has a crucial importance. routes vary over time partitioning
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2010 Why ad hoc networks?
The ad hoc networks can be deployed in a flexible manner in environments that have no fixed infrastructure
Having a fixed wired infrastructure or access points is not always possible or feasible It is not economically viable or interesting It is not practical in temporary environments It may have been destroyed, for example, due to natural disasters
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2010 A “clear” example: vehicular networks
About “smart cars” and “smart roads”. On-board systems “talk” with the “road”.
They car offer: Cooperative driver assistance:
Emergency notification Overtaking assistance Obstacle warning
Decentralized floating car data: Traffic jam monitor Dynamic navigation Route weather forecast
User communications and information services:
Hot-spot Internet access Inter-vehicle chat Distributed games
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REDES INALÁMBRICAS Máster de Ingeniería de Computadores-DISCA
Redes Inalámbricas – Tema 1 General concepts Redes Inalámbricas – Tema 1 General concepts
Applications: UBIQUITOUS COMPUTING
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Mark Weiser – The father of “Ubiquitous Computing” (1988)
Definitions Ubiquitous computing is the method of enhancing computer use by
making many computers available throughout the physical environment, but making them effectively invisible to the user
– Mark Weiser
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Mark Weiser (1952-1999) was the chief technology officer at Xerox’s Palo Alto Research Center (Parc). He is often referred to as the father of ubiquitous computing. He coined the term in 1988 to describe a future in which invisible computers, embedded in everyday objects, replace PCs. Other research interests included garbage collection, operating systems, and user interface design. He received his MA and PhD in computer and communication science at the University of Michigan, Ann Arbor. After completing his PhD, he joined the computer science department at the University of Maryland, College Park, where he taught for 12 years. He wrote or cowrote over 75 technical publications on such subjects as the psychology of programming, program slicing, operating systems, programming environments, garbage collection, and technological ethics. He was a member of the ACM, IEEE Computer Society, and American Association for the Advancement of Science. Weiser passed away in 1999. Visit www.parc.xerox.com/csl/members/weiser or contact [email protected] for more information about him.
Mark Weiser (1952-1999)
http://www-sul.stanford.edu/weiser/ M. Weiser, The Computer for the 21st Century Scientific American, 1991
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Ubiquitous Computing
What Ubiquitous Computing is: Information technology everywhere
Is a paradigm shift where technology becomes virtuallyinvisible in our lives “Calm Technology”
It needsSmart Objects embedded processorsWireless Technology to interconnect them
What Ubiquitous Computing is not: Mobility itself doesn’t lead to UbiComp Multimedia itself doesn’t lead to UbiComp either Virtual reality neither
Ubiquitous Computing: And old vision
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The new paradigm
Generic Features “Invisible” interfaces that
provideinteraction between user and application
Awareness of context Context information about the
environment with which theapplication is associated.
LOCATION and TIME are simple examples of context !
Capture experience To capture our day-to-day
experience and make it available for future use.
To acquires knowledge from places visited to server future visitors
Research challenges Multiple streams of information Their time synchronization Their correlation and integration
TransparentInterfaces
Awareness ofContext(s)
Capture Experience
Environment Preferences
AutoDiary
CAApp
Context Data LayerContext Data Layer
Sou
rces
Sin
ksSpa
ces
Sensor
PublicDisplay
ManualInput
ContextBrowser
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http://ttt.media.mit.edu/
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Redes Inalámbricas – Tema 1 General conceptsRedes Inalámbricas – Tema 1 General concepts
Applications: RURAL COMMUNICATIONS
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2010 Global survey on rural communications
Rural communications on the global agenda Connecting villages with Information and Communication Technologies
(ICT) and establishing community access points
Benefits E-business and e-commerce could play an important role in enabling
local artisans to reach national and international markets
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Yasuhiko Kawasumi, “Rural communications on the global agenda,” Global Survey on Rural Communications for the ITU-D on Communications for rural and remote areas.
Over 40% of the world’s population lives in rural and remote areas of developing countries and have difficult or no access to even basic telecommunications services. Development of telecommunications in rural and remote areas, therefore forms an important mission of the ITU Development sector.
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Needs of rural people in connection with e-services E-health, e-education and e-administration top the list as primary needs E-business and e-banking also scored highly
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ITU-D global survey, Doc 111/SG2
For many rural areas, electricity supply is simply non-existent or insufficient
Telemedicine Training in Bhutan by Tokai University: Tokai University Institute of Medical Sciences donated the medical equipments with ICT functions and provided the training on the use of equipments. Tokai University Second Opinion center provides the assistance service over the internet when requested by the Bhutanese ends.
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Optimal Technologies to connect Rural Communities
Question 1: What are the requirements for communications system in rural areas Implementation should be possible at a low cost in areas where
population density is low The system can be easily installed, even in remote and inaccessible
locations System operation and maintenance may be carried out even where
qualified technical personnel are scarce Implementation should be possible even when basic infrastructure such
as mains electricity, running water, paved road networks, etc., are absent
Long life cycles
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Optimal Technologies to connect Rural Communities
Question 2: What are the choices of technologies for communications in rural areas Satellite communications system (VSAT) Terrestrial wireless communications system
Wi-Fi, Wi-Max, 802.16 Mobile communications system (2G,GSM) Copper wire including power line The final report of ITU Focus Group 7 on “New
technologies for rural applications” (2001) recommended (WiFi) based on the IEEE 802.11 b/g
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Optimal Technologies to connect Rural Communities
Question 3: What is the advantage of wireless technologies for communications in rural areas Provide significant life time cost benefits in rural areas in cases where
cable deployment is uneconomic. Provide easy and speedy installation in harsh terrain and extremely
remote areas, smaller investment increments and avoidance of copper cable theft.
Provide lower maintenance cost and greater network flexibilities
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Optimal Technologies to connect Rural Communities
Question 4: What are the barriers for communications in the environment of rural areas Scarcity and absence of reliable electricity supply, water, access roads
and regular transport Scarcity of technical personnel Difficult topographical conditions (lakes, rivers, hills, mountains, or
deserts, etc.) Severe climatic conditions that make critical demands on the
equipment. Low level of economic activity mainly based on agriculture, fishing,
handicrafts, etc. Low per capita income Underdeveloped social infrastructure (health, education) Low population density Low literacy rate
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El Programa Telecentros
¿Qué es? El programa Telecentros se ha dirigido a los municipios de zonas rurales y a
núcleos urbanos desfavorecidos, a través de las Diputaciones, Cabildos y Consejos insulares o, en su caso, Comunidades Autónomas uniprovinciales. La actuación tuvo como principal objetivo facilitar el acceso a las nuevas tecnologías tanto a las poblaciones rurales como a los colectivos menos integrados, a fin de lograr su participación efectiva en la Sociedad de la Información.
La actuación tiene como principal objetivo facilitar el acceso a las nuevas tecnologías tanto a las poblaciones rurales como a los colectivos menos integrados, a fin de lograr su participación efectiva en la Sociedad de la Información.
Actuaciones: Conexiones a Internet de banda ancha en zonas rurales
y urbanas desfavorecidas. Equipamiento de los Centros de Acceso Público a Internet. Servicios de instalación, mantenimiento y atención al usuario. Servicios de control y gestión del Centro. Portales de servicios a poblaciones rurales. Servicios de dinamización y formación
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EU y las redes rurales
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Features Multi-hop Networks Automatic organization and maintenance Support for mobility (clients) Integration of technology access
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MIT Roofnet: http://pdos.csail.mit.edu/roofnet/doku.php Wireless access to the MIT Computer Science Lab
1,25 squared miles
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MIT Roofnet: Distribution of nodes
and quality of the links
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guifi.net
Public WiFi network deployed basically in Cataluña
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Kingsbridge Link http://www.kblink.co.uk/ Based on Linksys WRT54g
panOULU http://www.panoulu.net/ Finland
Meraki http://meraki.com/ San Francisco
Fon http://www.fon.com/es/
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REDES INALÁMBRICAS Máster de Ingeniería de Computadores-DISCA
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Applications: VANETs
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Safety and transport efficiency In Europe around 40,000 people die and more than 1.5 millions are
injured every year on the roads Traffic jams generate a tremendous waste of time and of fuel
Most of these problems can be solved by providing appropriate information to the driver or to the vehicle
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What’s in front of
that bus ?
What’s behind the
bend ?On rainy days
On foggy days
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VC promises safer roads,
… more efficient driving,
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… more fun,
… and easier maintenance.
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VANETs vs MANETs
Vehicular ad-hoc network (VANET) are a special case of Mobile ad-hoc networks (MANET) VANET constrained by
Predefined roads (e.g. one-way and multi-lane)Vehicle velocities restricted by speed limitsLevel of congestion in roads (e.g. urban or suburban)Traffic control mechanisms (e.g. traffic light)
VANET advantage by Rechargeable source of energyEquipped with devices with potentially longer transmission ranges.
(e.g. adopt WAVE and WiMAX) etc.
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VANETs vs MANETs
Rapid Topology Changes High relative speed of vehicles => short link life
Frequent Fragmentation Chunks of the net are unable to reach nodes in nearby regions
Small Effective Network Diameter A path may cease to exist almost as quickly as it was discovered
(reactive routing)
Limited Redundancy The redundancy in MANETs is critical to providing additional bandwidth In VANETs the redundancy is limited both in time and in function
REDES INALÁMBRICAS Máster de Ingeniería de Computadores-DISCA
Redes Inalámbricas – Tema 1General concepts Redes Inalámbricas – Tema 1General concepts
References
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References
Bibliografía Básica / Basic book The basic reference book for this course is "Wireless Networking in the
Developing World". This is a free book about designing, implementing, and maintaining low-cost wireless networks.
Reference books about advanced topics: "Wireless Communications: Principles and Practice (2nd Edition)",
Theodore S. Rappaport, Prentice Hall, January 2002. Available via Safari. "802.11 Wireless Networks: The Definitive Guide, Second Edition",
Matthew Gast, O'Reilly, April 2005. Available via Safari. "Ad Hoc Mobile Wireless Networks: Protocols and Systems", C. K. Toh,
Prentice Hall, 2001. Available via Safari. "Ad Hoc Wireless Networks Architectures and Protocols", C. Siva Ram
Murthy; B. S. Manoj, Prentice Hall, 2004. Available via Safari.
Documentación adicional para matriculados UPV Disponible en Poliformat
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de-facto standards “Rough consensus and running code”, D. Clark
Defined in documents called RFCs (Request For Comments) available on line: http://www.rfc-editor.org/
Phases: Proposed standards Draft Standard Internet Standard Before getting to RFC we use Internet-Drafts which are working
documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. https://datatracker.ietf.org/drafts/
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(Internet Architecture Board)IAB
IRTF IETFIETF
1983
1989
Internet SocietyInternet Society~1991
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Where to find up-to-date research references
Journals and Magazines: IEEE Network Magazine IEEE Communications Magazine IEEE Wireless Communications Magazine IEEE Pervasive Computing IEEE/ACM Transactions on Networking (TON) IEEE Transactions on Mobile Computing IEEE Journal on Selected Areas of Communications (JSAC)
Conferences: MOBICOM, MOBIHOC, PIMRC, MWCN... ICC, ISCC, ICCN GLOBECOM INFOCOM SIGCOMM
WWW http://www.grc.upv.es/links/ Web pages of research groups Google…
