Presentation on theme: "Redes Inalámbricas – Tema 1 General concepts"— Presentation transcript:
1Redes Inalámbricas – Tema 1 General concepts An overall view of:TechnologiesMANETs networksApplicationsDevicesReferencesAcknowledgmentsMark WeiserVint CerfJim Kurose, Keith Ross, “Computer Networking: A Top Down Approach Featuring the Internet, 2nd edition. Addison-Wesley, July 2002
2Redes Inalámbricas – Tema 1 General concepts Technologies
4Wireless Data Networks Wireless networks are the best option for mobile devices:Easy installation: no problems with cablesSystems easily expandable according to the needsLocal AreaPersonal AreaWide AreaWireless LAN IEEEPANBluetoothCellular Systems GSM, GPRS, EDGE UMTS
5Uses of WLANs “CORPORATE CAMPUS” “HOME OFFICE” “HOT SPOTS” COMMON AREAS,MEETING ROOMS,LABORATORIES,TEMPORARY OFFICE“HOT SPOTS”AIRPORTSHOTELSCONVENTION CENTER
7Mobility There are several types of mobility Physical mobility (of the devices)off line connectivity: portableon line connectivity : mobileLogical mobility:Of the processesOf the applications “ubiquitous computing”
8Mobility and the applications Bandwidth variabilityApplications should adapt. E.g., a videoconferencing application could vary the image size or its quality when varying the bandwidth.DisconnectionAllow asynchronous operations, pre-fetching, caching, weak consistency, ...Security and privacyThe 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, …
9General view“Mobile ad hoc networking: imperatives and challenges”, Imrich Chlamtac, Marco Conti, Jennifer J.-N. Liu, Ad Hoc Networks, Elsevier, 1 (2003).
10Redes Inalámbricas – Tema 1 General concepts Devices
11SensorsMica Hardware Platform: The Mica sensor node (left) with the Mica Weather Board developed for environmental monitoring applications
17Redes Inalámbricas – Tema 1 General concepts MANETs networks
18Mobile Ad-hoc Networks (MANETs) Networks formed by mobile wireless nodes.Do not use any existing infrastructureThere are hybrid solutions known as "mesh networks“In a MANET mobility has a crucial importance.routes vary over timepartitioning
19Why ad hoc networks?The ad hoc networks can be deployed in a flexible manner in environments that have no fixed infrastructureHaving a fixed wired infrastructure or access points is not always possible or feasibleIt is not economically viable or interestingIt is not practical in temporary environmentsIt may have been destroyed, for example, due to natural disasters
20A “clear” example: vehicular networks About “smart cars” and “smart roads”. On-board systems “talk” with the “road”.They car offer:Cooperative driver assistance:Emergency notificationOvertaking assistanceObstacle warningDecentralized floating car data:Traffic jam monitorDynamic navigationRoute weather forecastUser communications and information services:Hot-spot Internet accessInter-vehicle chatDistributed games
21Redes Inalámbricas – Tema 1 General concepts Applications: UBIQUITOUS COMPUTING
22Ubiquitous Computing Mark Weiser Definitions – Mark Weiser – The father of “Ubiquitous Computing” (1988)DefinitionsUbiquitous 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 WeiserMark Weiser ( ) 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 Visit or contact for more information about him.Mark Weiser ( )M. Weiser, The Computer for the 21st Century Scientific American, 1991
23Ubiquitous Computing What Ubiquitous Computing is: Information technology everywhereIs a paradigm shift where technology becomes virtually invisible in our lives “Calm Technology”It needsSmart Objects embedded processorsWireless Technology to interconnect themWhat Ubiquitous Computing is not:Mobility itself doesn’t lead to UbiCompMultimedia itself doesn’t lead to UbiComp eitherVirtual reality neitherUbiquitous Computing: And old vision
24The new paradigm Generic Features “Invisible” interfaces that provide interaction between user and applicationAwareness of contextContext information about the environment with which the application is associated.LOCATION and TIME are simple examples of context !Capture experienceTo capture our day-to-day experience and make it available for future use.To acquires knowledge from places visited to server future visitorsResearch challengesMultiple streams of informationTheir time synchronizationTheir correlation and integration
26Redes Inalámbricas – Tema 1 General concepts Applications: RURAL COMMUNICATIONS
27Global survey on rural communications Rural communications on the global agendaConnecting villages with Information and Communication Technologies (ICT) and establishing community access pointsBenefitsE-business and e-commerce could play an important role in enabling local artisans to reach national and international marketsOver 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.Yasuhiko Kawasumi, “Rural communications on the global agenda,” Global Survey on Rural Communications for the ITU-D on Communications for rural and remote areas.
28Rural populations and their ICT needs Needs of rural people in connection with e-servicesE-health, e-education and e-administration top the list as primary needsE-business and e-banking also scored highlyITU-D global survey, Doc 111/SG2For many rural areas, electricity supply is simply non-existent or insufficientTelemedicine 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.
29Optimal Technologies to connect Rural Communities Question 1: What are the requirements for communications system in rural areasImplementation should be possible at a low cost in areas where population density is lowThe system can be easily installed, even in remote and inaccessible locationsSystem operation and maintenance may be carried out even where qualified technical personnel are scarceImplementation should be possible even when basic infrastructure such as mains electricity, running water, paved road networks, etc., are absentLong life cycles
30Optimal Technologies to connect Rural Communities Question 2: What are the choices of technologies for communications in rural areasSatellite communications system (VSAT)Terrestrial wireless communications systemWi-Fi, Wi-Max,Mobile communications system (2G,GSM)Copper wire including power lineThe final report of ITU Focus Group 7 on “New technologies for rural applications” (2001) recommended (WiFi) based on the IEEE b/g
31Optimal Technologies to connect Rural Communities Question 3: What is the advantage of wireless technologies for communications in rural areasProvide 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
32Optimal Technologies to connect Rural Communities Question 4: What are the barriers for communications in the environment of rural areasScarcity and absence of reliable electricity supply, water, access roads and regular transportScarcity of technical personnelDifficult 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 incomeUnderdeveloped social infrastructure (health, education)Low population densityLow literacy rate
33El 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
35Mesh Networks Features Multi-hop Networks Automatic organization and maintenanceSupport for mobility (clients)Integration of technology access
36MIT Roofnet: Distribution of nodes and quality of the links Wireless access to the MIT Computer Science Lab1,25 squared milesMIT Roofnet: Distribution of nodes and quality of the links
37guifi.netPublic WiFi network deployed basically in Cataluña
38Other proposals Kingsbridge Link panOULU Meraki Fon Based on Linksys WRT54gpanOULUFinlandMerakiSan FranciscoFon
39Redes Inalámbricas – Tema 1 General concepts Applications: VANETs
40Motivation Safety and transport efficiency In Europe around 40,000 people die and more than 1.5 millions are injured every year on the roadsTraffic jams generate a tremendous waste of time and of fuelMost of these problems can be solved by providing appropriate information to the driver or to the vehicle
41Passive Approach is not Enough On foggy daysWhat’s in front of that bus ?What’s behind the bend ?On rainy days
42Vehicle Communication (VC) VC promises safer roads,… more efficient driving,
43Vehicle Communication (VC) … more fun,… and easier maintenance.
46VANETs vs MANETsVehicular ad-hoc network (VANET) are a special case of Mobile ad-hoc networks (MANET)VANET constrained byPredefined 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 byRechargeable source of energyEquipped with devices with potentially longer transmission ranges. (e.g. adopt WAVE and WiMAX)etc.Vehicular ad-hoc network (stand for VANET) is a special case of mobile ad-hoc networks.
47VANETs vs MANETs Rapid Topology Changes Frequent Fragmentation High relative speed of vehicles => short link lifeFrequent FragmentationChunks of the net are unable to reach nodes in nearby regionsSmall Effective Network DiameterA path may cease to exist almost as quickly as it was discovered (reactive routing)Limited RedundancyThe redundancy in MANETs is critical to providing additional bandwidthIn VANETs the redundancy is limited both in time and in function
48Redes Inalámbricas – Tema 1 General concepts References
49References 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 Available via Safari." Wireless Networks: The Definitive Guide, Second Edition", Matthew Gast, O'Reilly, April Available via Safari."Ad Hoc Mobile Wireless Networks: Protocols and Systems", C. K. Toh, Prentice Hall, Available via Safari."Ad Hoc Wireless Networks Architectures and Protocols", C. Siva Ram Murthy; B. S. Manoj, Prentice Hall, Available via Safari.Documentación adicional para matriculados UPVDisponible en Poliformat
50(Internet Architecture Board) Standards en Internetde-facto standards“Rough consensus and running code”, D. ClarkDefined in documents called RFCs (Request For Comments) available on line:Phases: Proposed standards Draft Standard Internet StandardBefore 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/(Internet Architecture Board)IABIRTFIETF19831989Internet Society~1991
51Where to find up-to-date research references Journals and Magazines:IEEE Network MagazineIEEE Communications MagazineIEEE Wireless Communications MagazineIEEE Pervasive ComputingIEEE/ACM Transactions on Networking (TON)IEEE Transactions on Mobile ComputingIEEE Journal on Selected Areas of Communications (JSAC)Conferences:MOBICOM, MOBIHOC, PIMRC, MWCN...ICC, ISCC, ICCNGLOBECOMINFOCOMSIGCOMMWWWWeb pages of research groupsGoogle…