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By Kannikar Siriwong Na Ayutaya

By Kannikar Siriwong Na Ayutaya. Low Overhead With Speed Aware Routing (LOWSAR) in VANETs. Outline. Problem Routing Mechanism Related Works Objective Contention-based Routing (CBR) Algorithm Motivation LOWSAR Algorithm Results Conclusion and Future works. Why need routing for VANETs?.

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By Kannikar Siriwong Na Ayutaya

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  1. By Kannikar Siriwong Na Ayutaya Low Overhead With Speed Aware Routing (LOWSAR) in VANETs

  2. Outline • Problem • Routing Mechanism • Related Works • Objective • Contention-based Routing (CBR) Algorithm • Motivation • LOWSAR Algorithm • Results • Conclusion and Future works

  3. Why need routing for VANETs? • Reasons: High mobility and frequent network disconnection and merging • Result: Topology-based routings in MANETs are NOT suitable for VANETs • Solutions: Position-based routing and Contention-based routing

  4. VANETs Routing Mechanism • Beaconing: periodically exchange location message between vehicles • Location service: process of searching for unknown destination location • Forwarding: transmitting packets to destination (unicast, broadcast, anycast, scan)

  5. Position-based Routing(PBR) Neighbor positions obtained by beaconing Routing decision is done locally by one node at a time Contention-based Routing(CBR) Routing decision is done in distributed manner without beaconing Related Works

  6. 2 1 3 4 Related Works • Position-based Routing(PBR) • Contention-based Routing(CBR) 2 1 3 4

  7. PBR Outdated neighbor positions High routing decision computational complexity Increase message exchanging overhead Enhance packet collision Eliminate packet redundancy CBR Eliminate beaconing overhead during routing decision Create possibility of packet redundancy Related Works (Pros & Cons)

  8. Objective • Extend contention-based routing (CBR) to account for speed of vehicles • Propose LOWSAR algorithm to speed up data delivery delay

  9. Basic CBR Algorithm (Terminology) • T = constant bias clock delay • r = transmission range • Dmn = distance from nodem to noden • d = bias clock delay • W = ratio of difference of distance and r

  10. d = T(1 – W) Basic CBR Algorithm D15 W = (D15 – D35)/r ≤ 1 D35 3 D15 – D35 D15 1 5 r

  11. Basic CBR Algorithm D15 d = T d > T d < T 6 3 1 7 5 2 4 W = (D17 – Di7)r, i = 2,…,6 d = T(1 – W)

  12. Basic CBR Algorithm D15 d = T(1-(D15 – D 15)/r) = T d = T(1-(D15 – D35)/r) r D35 3 D15 – D35 D15 1 5 D25 2 d = T(1-(D15 – D45)/r) > T D15 – D25 D45 4 D15 – D45 < 0 d = T(1-(D15 – D25)/r)

  13. C A Problem: Location Dominated Forwarding VCt B VBt VAt

  14. Problem: Speed Dominated Forwarding C B VC= 0 A VA > 0

  15. LOWSAR Algorithm • V = vicinity of a vehicle • D = distance from a node to destination d = min{ T(1 – W), T(1 – W)/V, T( D/r - 1)}

  16. Preliminary Results

  17. Conclusion and Future Works • Under different speed limits, LOWSAR outperforms CBR in terms of delivery delay • Explore effects of other parameters on delivery delay • Number of source nodes • Data rate • Number of vehicles (traffic density)

  18. Conclusion and Future Works • Investigate on other performance metrics • Average number of hops to a destination • Packet delivery ratio • Compare these performance with other compatible routing algorithms

  19. Thank you!

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