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CMPE 257: Wireless Networking

CMPE 257: Wireless Networking. Disruption Tolerant Networking. Outline. Motivation Open problems Examples of state of the art and future work Key Message: There is much to be done!. Motivation. Motivation.

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CMPE 257: Wireless Networking

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  1. CMPE 257: Wireless Networking Disruption Tolerant Networking UCSC CMPE257

  2. Outline • Motivation • Open problems • Examples of state of the art and future work Key Message: There is much to be done! UCSC CMPE257

  3. Motivation UCSC CMPE257

  4. Motivation • Provide access to information, people, and services even when physical connectivity is sporadic or disrupted frequently. • Opportunistic use of available resources • Example applications: • Interplanetary internetworking • Networks in battlefield and disaster relief • Environmental and wild-life monitoring • Developing regions • Vehicular networks • Peer-to-peer systems and opportunistic messaging UCSC CMPE257

  5. End-to-end information flow across the solar system • Layered architecture for evolvability and interoperability • IP-like protocol suite tailored to operate over long round trip light times • Integrated communications and navigation services UCSC CMPE257

  6. Extremely LongPropagation Delays UCSC CMPE257

  7. Challenges with Interplanetary Internet • Extremely long and variable propagation delays • Asymmetrical forward and reverse link capacities • Extremely high link error rates • Intermittent link connectivity, e.g., Blackouts • Power, mass, size, and cost constraints for communication hardware and protocol design • However, links have predictable on-off schedules! UCSC CMPE257

  8. History of Delay Tolerant Networking (DTN) (Source: “Delay Tolerant Networking,” S. Burleigh et al, 24 April 2003) UCSC CMPE257

  9. History of Delay Tolerant Networking (DTN) (Source: “Delay Tolerant Networking,” S. Burleigh et al, 24 April 2003) UCSC CMPE257

  10. Environmental Monitoring Link on-off schedules are random because of subject under observation or equipment constraints. Some nodes can move randomly or with controlled/known routes (source: EPFL) (source: Intel) UCSC CMPE257

  11. Battlefield and Disaster Relief z End-to-end connectivity need not ever exist and links (contacts) may not be suitable for schedules UCSC CMPE257

  12. Healthcare Monitoring Networks • Personal area networks • Subjects may have on-off connectivity with environment • Self configuring Source: Wellness environments UCSC CMPE257

  13. VANETs: Car to Car Communication Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 65 mphAcceleration: - 5m/sec^2Coefficient of friction: .65Driver Attention: YesEtc. Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 75 mphAcceleration: + 20m/sec^2Coefficient of friction: .65Driver Attention: YesEtc. Alert Status: None Alert Status: None Alert Status: Inattentive Driver on Right Alert Status: Slowing vehicle ahead Alert Status: Passing vehicle on left Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 45 mphAcceleration: - 20m/sec^2Coefficient of friction: .65Driver Attention: NoEtc. Vehicle type: Cadillac XLRCurb weight: 3,547 lbsSpeed: 75 mphAcceleration: + 10m/sec^2Coefficient of friction: .65Driver Attention: YesEtc. Alert Status: Passing Vehicle on left (Source: M. Gerla, UCLA)

  14. Dedicated Short Range Communications (DSRC)/802.11p • Car-Car communications in 5.9Ghz frequency band • Range of 1 Km • Node speeds up to 85mph • Data rates of 6 to 27 Mbps (depending on range) • Derived from 802.11a • three types of channels: Vehicle-Vehicle service, a Vehicle-Gateway service and a control broadcast channel . • Ad hoc mode and infrastructure mode • 802.11p: IEEE Task Group that intends to standardize DSRC for Car-Car communications • Same problems as 802.11a/b/g in MANETs

  15. Hot Spot Hot Spot (Source: M. Gerla, UCLA) Vehicular Grid as Opportunistic Ad Hoc Net

  16. Power Blackout Power Blackout Hot Spot Hot Spot (Source: M. Gerla, UCLA) Vehicular Grid as Emergency Net

  17. Power Blackout Power Blackout (Source: M. Gerla, UCLA) Vehicular Grid as Emergency Net

  18. Commercial Market?“Opportunistic” MANETs Connectivity is a problem because of market penetration and node density UCSC CMPE257

  19. h Example Application:A Self-Organizing Wireless Messaging Network (SOWER) Each user owns: home device mobile device m • Home devices are: • power plugged – always on • static devices • same radio as mobiles Home devices form a wireless backbone for message transmission Source: SOWER: “Self-­Organizing Wireless Network for Messaging,” Mark Felegyhazi, Srdjan Capkun and Jean-Pierre Hubaux , Tech Rept. IC/2004/62 UCSC CMPE257

  20. Penetration Requirements Scenario ultra-modern (Manhattan) modern (Berlin) historic (Rome) small (Berkeley) Population density (persons/km2) 25850 12500 8177 2260 Required device density (devices/km2) 5000 3000 700 380 Required market penetration (simulation for 100mW) 0.193 0.24 0.086 0.168 Required market penetration (calculated for 1W, α=5) 0.06 0.05 0.02 0.04 Source: SOWER: “Self-­Organizing Wireless Network for Messaging,” Mark Felegyhazi, Srdjan Capkun and Jean-Pierre Hubaux , Tech Rept. IC/2004/62 More information: http://lcawww.epfl.ch/felegyhazi/ UCSC CMPE257

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