Copyright © 2011, A Road-based QoS-aware Multipath Routing for Urban Vehicular Ad Hoc Networks 指導教授：王國禎 學生：謝宜玲 國立交通大學資訊科學與工程研究所 行動計算與寬頻網路實驗室 1

Copyright © 2011, Outline Introduction Related work Proposed multipath routing protocol for urban VANETs (MRV) –Multiple road-disjoint paths discovery –Path life time and life periods prediction –Dynamic QoS path switching Simulation Conclusion References 2

Copyright © 2011, Introduction – Motivation Stable and efficient routing plays a key role for the success of VANETs Road-based routing has been shown well- suited in urban VANETs [5][8] –(better than traditional node-based routing) Multipath routing provides alternative routes once the current route fails  However, existing multipath routing protocols are node-based, which are not suitable for urban VANETs 3

Copyright © 2011, Introduction – Routing in VANETs Road-based routing vs. node-based routing –Node-based routing: sensitive to node mobility –Road-based routing: depending on node density As long as the node density is not sparse in each road section of a path, the whole path is connected –Node density does not vary too much in a road section, in a short period It has more choices of next hop  Road-based routing is steadier than node-based routing, for urban VANETs 4

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Introduction – Multipath routing Multipath routing –further enhance the route stability 1.provides alternative routes once the current route fails 2.provides concurrent transmission with multiple paths (optional) Existing multipath routing protocols –are node-based (not road-based) –potential drawback: potential transmission interference if they are multiple paths through the same road sections [14] 6

Copyright © 2011, Introduction – QoS routing QoS routing in urban VANETs –Utilize probability of connectivity and hop count to decide the best QoS path –derive/estimate probability of connectivity and hop count with vehicles mobility data (e.g. speed, position, node density) Most of current QoS routing protocols for VANETs are node-based –derive a route’s QoS along with route discovery –only consider straight roads (e.g. highways) or limited local roads due to inherited weakness of node-based routing  For generic city road topologies, road-based routing approach is preferred Road-based QoS routing –IGRP [5]: directly determine a path’s with the assistance of traffic statistics Additional traffic statistics is required; however, it may not reflect the current situation 7

Copyright © 2011, Introduction – the proposed routing protocol We propose a road-based QoS-aware multipath routing protocol for urban VANETs (MRV) 1.MRV can find multiple road-disjoint paths 2.Predict a path’s future lifetime and life periods to adaptively utilize multiple paths –We propose a space-time planar approach to predict the connectivity of each road section in a path 3.Dynamic QoS path switching –dynamically switch to a path that satisfies the packet delay constraint Packet delay is estimated according to a path’s life periods 8

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Copyright © 2011, Related work Expected results Contribution of MRV over other road-based routing protocols –Provide multiple path and consider QoS (vs. RBVT-R) –On-demand route discovery (vs. IGRP) 10

Copyright © 2011, Proposed multipath routing protocol for urban VANETs (MRV) 11 Problem description 1.How to find multiple road-disjoint paths? 2.Among the multiple paths, we choose the path with longest lifetime  How to estimate a road section’s lifetime so as to derive a path’s lifetime 3.As time elapses, a road section becomes connected or disconnected  How to dynamically switch to another path

Copyright © 2011, Proposed MRV – multipath discovery Multipath discovery (route discovery, RD) –RD packet: [src, dest, seq #, road section list (RS list)] generated at source and being flooded out, until reaching destination –The RS list in an RD packet is updated when the packet enters a new road section –RD packet table Every node maintains one, to check whether a received RD packet had been seen 1.Road-disjoint paths RD packet with duplicate RS is dropped (disregarding the beginning and ending RSs) However, duplicate RSs are allowed if not enough multiple paths are available 2.Loop detection e.g. a node in RS3 received an RD packet with RS list [5, 3, 2, 7, 8] 12

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Copyright © 2011, Proposed MRV – multipath discovery Route reply –For each RD packet, the destination node sends a route reply (RR) packet to the source node –Along with the RR packet being relayed among RSs, the path’s future connectivity prediction is processed in each RS 14

Copyright © 2011, Road section connectivity problem 15 Geographical forwarding –used to relay data packets through a road section Every node maintains a neighbor table for choosing next hop neighbor table: every node periodically broadcast a HELLO

Copyright © 2011, Road section connectivity problem 16 A potential problem and its solution –As time elapses, a road section may become connected or disconnected, due to node mobility  RS life periods prediction  path life periods  path switching before disconnection

Copyright © 2011, Road section connectivity problem – space-time planar approach  We propose a space-time planar approach to formulate and resolve the road section connectivity problem –A road section’s life period can be derived  A path’s life period is then derived 17

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Copyright © 2011, Path lifetime estimation and QoS path switching 19 RS life periods is included in the RR packet –RR packet piggybacks the relay nodes’ neighbor tables –The last node in the RS, e.g. node i, calculates RS C 1 - C 2 ’s life periods using the space-time planar approach –Intersect the derived life periods with the existing life periods piggybacked in the RR packet (so as to reduce RR packet size) The piggybacked neighbor tables are also removed

Copyright © 2011, QoS path switching 20 The source node may switch to a path which is connected currently or satisfies delay constraint –Small gaps may be tolerated because of using carry- and-forward

Copyright © 2011, QoS path switching 21 Packet delay d i for path i is due to two kinds of delay –Transmission delay (d p ) –Path disconnection delay (d d ) –d i = d p (i) + d d (i)

Copyright © 2011, QoS path switching 22 Transmission delay (d p ) –d ij : packet delay through RS ij, d ij = t p *{2+[(L ij – 2*s)/(T r /2)]} t p is transmission delay of a hop, which is regarded as a constant [8] –d p (i) = ∑d ij, for RS ij in path i Path disconnection delay (d d ) –d d is the sum of the mean of each disconnection period

Copyright © 2011, Simulation 23 Simulator: QualNet 5.0 Map: a grid map of 1000m x 1000m with 200m interval [8] Total 200 nodes Node mobility trace generator: VanetMobiSim –node speed: [0m/s, 20m/s] Radio range: 275m [8] Two-ray ground propagation model [8] –With NLOS, only nodes in adjacent road sections are allowed for radio communication

Copyright © 2011, Simulation We expect that MRV will have significant higher packet delivery rate, shorter packet delay and lower control overhead than a single-path road-based routing protocol, RBVT-R, and a traditional multipath routing protocol, AOMDV Expected results 24

Copyright © 2011, Conclusion We have presented a road-based QoS-aware multipath routing protocol for urban VANETs (MRV) MRV is used to find multiple road-disjoint paths and to estimate paths' future life periods for QoS path switching A space-time planar approach has been proposed to predict each road section’s connectivity of a path and to derive a path’s future lifetime and life periods 25

Copyright © 2011, Conclusion We expect that MRV will have significant higher packet delivery rate, shorter packet delay and lower control overhead than a single-path road-based routing protocol, RBVT-R, and a traditional multipath routing protocol, AOMDV To the best of our knowledge, there is no road-based multipath routing protocol in literature 26

Copyright © 2011, References 27 1.M. K. Marina and S. R. Das, "Ad hoc on-demand multipath distance vector routing," Wireless Communications and Mobile Computing, pp , Cheng-Shiun Wu, Shuo-Cheng Hu and Chih-Shun Hsu” Design of fast restoration multipath routing in VANETs", in Proc. of Computer Symposium (ICS), pp , S.-J. Lee, M. Gerla,"Split Multipath Routing with Maximally Disjoint Paths in Ad Hoc Networks," IEEE International Conference on Communications, vol. 10, pp , X. Huang and Y. Fang, "Performance Study of Node-Disjoint Multipath Routing in Vehicular Ad Hoc Networks," vol. 58, issue 4, pp , 2009.

Copyright © 2011, References 28 5.H. Saleet et al., "Intersection-based geographical routing protocol for VANETs: a proposal and analysis," IEEE Transactions on Vehicular Technology, vol. 60, issue 9, pp , Nov M. Jerbi, S.-M. Senouci, R. Meraihi and Y. Ghamri-Doudane, "An improved vehicular ad hoc routing protocol for city environments," in Proc. of IEEE International Conference on Communications (ICC), pp , K. Lee, M. Le, J. Haerri and M. Gerla, "Louvre: Landmark overlays for urban vehicular routing environments," in Proc. of IEEE VTC, pp. 1-5, J. Nzouonta et al., "VANET routing on city roads using real- time vehicular traffic information," IEEE Transactions on Vehicular Technology, vol. 58, issue 7, pp , 2009.

Copyright © 2011, References 29 9.H. Rongxi,H. Rutagemwa and S. Xuemin, "Differentiated reliable routing in hybrid vehicular ad-hoc networks," in Proc. of International Conference on Communications, pp , May Cheng-Shiun Wu, Shuo-Cheng Hu and Chih-Shun Hsu” Design of fast restoration multipath routing in VANETs", in Proc. of Computer Symposium (ICS), pp , S. Bitam and A. Mellouk, "QoS swarm bee routing protocol for vehicular ad hoc networks," in Proc. of International Conference on Communications (ICC), pp. 1- 5, June Z. Mo, H. Zhu, K. Makki and N. Pissinou, "MURU: A multi-hop routing protocol for urban vehicular ad hoc networks," in Proc. of 3rd Annual International Conference on Mobile and Ubiquitous Systems, 2006, pp. 1–8, 2006.

Copyright © 2011, 13.Y. Gongjun, D.B. Rawat and B.B. Bista, "Provisioning vehicular ad hoc networks with quality of service," in Proc. of International Conference on Broadband, Wireless Computing, Communication and Applications(BWCCA), pp , Yufeng Chen, Zhengtao Xiang, Wei Jian and Weirong Jiang, "An Adaptive Cross-Layer Multi-Path Routing Protocol for Urban VANET," in Proc. of the IEEE International Conference on Automation and Logistics, pp. 603 – 608, Xiaoxia Huang and Yuguang Fang, "Performance Study of Node- Disjoint Multipath Routing in Vehicular Ad Hoc Networks," IEEE Transactions on Vehicular Technology, vol. 54, issue 4, pp , Yi-Ling Hsieh and Kuochen Wang, “Road Layout Adaptive Overlay Multicast for Urban Vehicular Ad Hoc Networks,” in Proc. of the IEEE 73 rd VTC, pp. 1-5, (submitted to journal Computer Networks) 30