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Vehicular Networks

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Vehicular Networks

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  1. Vehicular Networks Slides are integrated from researchers at EPFL

  2. Outline • Why vehicular networks • Technical challenges • Conclusion

  3. Outline • Why vehicular networks • Technicals • Applicaitions • Wireless Urban Grid • Technical challenges • Conclusion

  4. Vehicular communications: why? • Combat the awful side-effects of road traffic • Fatal losses yearly on the roads; and injured (huge numbers) • 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

  5. A modern vehicle is a computer on wheels (GPS) - Human-Machine Interface - Navigation system • Processing power: comparable with a Personal Computer + a few dozens of specialized processors • Communication: typically over a dedicated channel:Dedicated Short Range Communications (DSRC) • In the US, 75 MHz at 5.9 GHz; • In Europe, 20 MHz requested but not yet allocated) • Protocol: IEEE 802.11p • Penetration will be progressive (over 2 decades or so)

  6. Example of service: electronic brake warning • Similar services: • Road condition warning • Emergency vehicle approaching

  7. Other example of service: traffic information

  8. Liability-related messages • The information carried by these messages is susceptible to be stored in the Event Data Recorder of each vehicle

  9. Another application : SmartPark Park! Turn left! 30m to go… Turn right! 50m to go…

  10. Other examples of services based on vehicular networks (these ones usually involve road side infrastructure) • Vehicle to road • Electronic toll collection • Vehicles as probes to collect traffic data • Ramp metering to reduce congestion • Road to vehicle • Signal violation warning • Intersection collision warning • Data downloads

  11. Message categories and properties Real-timecons-traints D: Destination R: Relay S: Source

  12. Outline • Why vehicular networks • Technicals • Applicaitions • Wireless Urban Grid (another file) • Technical challenges • Conclusion

  13. Outline • Why vehicular networks • Technical challenges • Service penetration and connectivity • Research opportunities in the vehicular networks • Conclusion

  14. Vehicular communications:a compelling (and tough) research challenge • High speed of the nodes (relative speed up to 500 km/h) • Real time constraints (milliseconds) • Sporadic connectivity (a few seconds or less) • Crucial role of the geographic position of the nodes • Very gradual penetration • Last but not least, a very specific security research question

  15. Penetration and connectivity First level approximation:

  16. Number of hops Vs penetration (1/2)

  17. Hopping on vehicles in the reverse direction

  18. Number of hops Vs penetration (2/2)

  19. compute connectivity in this case

  20. Performance evaluation • Two scenarios drawn from DSRC • ns-2 simulations; single-hop transmission • Effect of message size (including the security overhead) on delay and number of received packets (Not to scale) (Not to scale) Rough estimate of incoming traffic: 36 veh * 10 msg/(veh*s) * 800 Bytes/msg = approx. 3 Mb/s Rough estimate of incoming traffic: 120 veh * 3.33 msg/(veh*s) * 800 Bytes/msg = approx. 3 Mb/s

  21. Delay Vs message size RSA NTRU ECDSA No security

  22. Received packets Vs message size RSA NTRU ECDSA No security

  23. Factors in performance evaluation of vehicular networks • Nature of data traffic (e.g., single hop, geocast) • Available spectrum (e.g., 75 MHz or 20MHz around 5.9 GHz) • Radio propagation model in vehicular environment • Kind of antenna (directional or not) • Number of radios • Penetration rate (e.g., parameter from 5% to 100%) • Considered crypto algorithm • Vehicle mobility models • Road topology • Amount of roadside infrastructure (e.g., none) Powercontrol • Connectivity • Goodput • Delay • Delay jitter • Fairness Performanceevaluation • Examples of design questions: • Is CSMA/CA really the best solution? • To what extent can geographic position be taken into account for routing?

  24. Conclusion • The performance of vehicular communications is a difficult and highly relevant problem • Car manufacturers seem to be poised to massively invest in this area • Slow penetration makes connectivity more difficult • Security leads to a substantial overhead and must be taken into account from the beginning of the design process • The field offers plenty of novel research challenges • M. Raya and J.-P. Hubaux, “The Security of Vehicular Ad Hoc Networks”, Workshop on Secure Ad Hoc and Sensor Networks (SASN) 2005

  25. Events and resources • Conferences and journals • VANET, colocated with Mobicom • V2V-Com, co-located with Mobiquitous • WIT: Workshop on Intelligent Transportation • VTC: Vehicular Technology Conference • IV: Conference on Intelligent Vehicles • IEEE Transactions on Intelligent Transportation Systems • IEEE Transactions on Vehicular Technology