VANET

VANET& Geographic Routing SpeakerDate2010/04/14

11OutlinePart IVANET VANETPart IIGeographic Routing in City ScenariosPart IIIConclusions and Future work2OutlinePart IVANET VANETPart IIGeographic Routing in City ScenariosPart IIIConclusions and Future work3VANET

Vehicular Ad Hoc NetworkVANET

4VANET VANETIEEE 802.11b (Wi-Fi) IEEE 802.11p IEEE 802.16 (WiMax)VANETVANET 5VANETMANETVANETMANETVANETMANET6

VANETMANET

7OutlinePart IVANET VANETPart IIGeographic Routing in City ScenariosPart IIIConclusions and Future work8VANETVANET

VANET 9VANETRoadside-to-Vehicle CommunicationsRVC APbase stationserver

Roadside-to-Vehicle Communications RVC10Roadside-to-Vehicle Communications

a. Mobility management VANETnodeAPAP(handover)

b. Choosing Internet gateway: APAPhop 11VANETInter-Vehicle Communications (IVC) AP

Inter-Vehicle Communications IVC12IVC RoutingUnicast RoutingCluster-Based RoutingGeocast RoutingBroadcast Routing13Unicast Routingrouting protocol 14

IVC routing protocol Unicast routingTopology-based routing protocols Proactive tabletabletableReactive 15Unicast routingGeographic routing

header(GPS)

one-hop neighborsone-hop neighborsone-hop neighbors 16Geographic routingGeographic routing None-DTN (Non-Delay tolerant network) DTN (delay tolerant network) Hybrid 17None-DTNprotocolVANETGreedy forwardingGreedy forwardinglocal maximumrouting protocollocal maximumGPSR, CAR, A-STAR, STBR18Greedy forwardingAn intermediate nodes forward a packet to the direct neighbor which is closest to the geographic position of destination

19Local maximum

20Greedy Perimeter Stateless Routing (GPSR)

Perimeter Forwarding21DTNDTN(carry-and-forward)VADD, GeOpps22 Hybridnone-DTNDTNnone-DTNgreedy modeDTNcarry-and-forwardnone-DTNnone-DTNDTNhop,, 23IVC RoutingUnicast RoutingCluster-Based RoutingGeocast RoutingBroadcast Routing24Cluster-Based Routing

25Geocast RoutingThe multicast of a message, using geographic routing, to nodes satisfying a geographical criterion is called geocast.

26Zone of Relevance, ZORgeocast routingfloodingfloodingsimple flooding

26Broadcast RoutingBroadcastVANET

floodingFloodingFlooding2727VANETHybrid Vehicular Communication Systems (HVC) IVCRVCAPIVCserverrouterAP

RVCIVC28SummaryRVCIVCHVCMobility management Choosing Internet gatewayUnicast RoutingCluster-Based RoutingGeocast RoutingBroadcast RoutingVANET2929OutlinePart IVANET VANETPart IIGeographic Routing in City ScenariosPart IIIConclusions and Future work30Geographic Routing in City ScenariosChristian Lochert, Martin Mauve, Holger FuBler, Hannes Hartenstein

ACM SIGMOBILE Mobile Computing and Communications Review, 200531IntroductionIt is related to the idea of position-based source routing as proposed for terminode routing.The static street map is need due to its algorithm.This paper provide a method without assumption thatNodes have access to a static street map andWithout using source routing32ideaTerminode RoutingGPSpapersource routing

32Position-based RoutingGreedy forwardingAn intermediate nodes forward a packet to the direct neighbor which is closest to the geographic position of destinationFor this task, nodes has to be aware ofIts own positionThe position of its direct neighborsThe position of the final destination

3333Local maximum Problem

34Greedy Perimeter Coordinator RoutingWithout using any global information such as static map.GPCR consists of two parts:A restricted greedy forwardA repair strategy based on the topology of real-world streets and junctionsTherefore, it doesnt require a graph planarization algorithm.

35GPCRGPCR greedy forward 35Restricted Greedy RoutingJunctions are only places where actual decision are takenPackets should always be forwarded to a node on a junction rather than across a junctionIf the forwarding nodes are all not located on a junction, chose the node thatApproximates an extension of the line between forwarding nodes predecessor and itself.

36forwarding node Greedy Routingnext hop36Restricted Greedy Routing (cont.)

Greedy Routing vs. Restricted GreedyRouting in the area of a junction.37Source : UDestination : D Greedy Routing U next hop1a forwarding 2a-> 2b->D

GPCR U next hop Coordinator 2aCoordinatorhop 2b->D37Restricted Greedy Routing (cont.)

38B AAnext hoprandom3a38Repair StrategyAs a consequence the repair strategy of GPCR consists of two parts: (1) On each junction it has to be decided which street the packet should follow next.(2) In between junctions greedy routing to the next junction, as described above, can be used.39packetpacket greedy routing 39Example A packet with destination D reaches a local maximum at node S. The forwarding of the packet is then switched to the repair strategy and it is routed along the street until it hits the first coordinator node.

40SdataDlocal maximum(SSD) greedy routing next hopforwarding40Detecting junctionsBy observing the beacon messages a node has the following information for each neighbor: its position and the position and presence of the neighbors neighbors.xyz41one-hop neighborsx yzX41Detecting junctionsWe dene xi and yi as the x-coordinate and y-coordinate of a node i.The variables x and y subsume the population of all these positions xi and yi respectively.The mean of a population x is marked by x

4242Cont.A correlation coefcient close to 1 indicates a linear coherence as it is found when the node is located in the middle of a street A correlation coefcient close to 0 shows that there is no linear relationship between the positions of the neighbors. Consequentially we conclude that the node is located on a junction431043 Simulation ResultsFor the simulations we used a real city topology which is a part of Berlin,Germany. The scenario consists of 955 cars (nodes)on 33 streets in an area of 6.25 km *3.45 kmIEEE 802.11 was used as MAC with a transmission rate of 2 Mbps. The transmission range was set to 500 m. 44GPCR vs. GPSR. Delivery rate

45CC neighbor tables(NT)45GPCR vs. GPSR. Delivery rate

46 Conclusions and Future workOur approach does not require external information such as a static street map to avoid the problems that existing position-based approaches face in this type of environmentFuture improvementCurrently the next street to be taken is determined without considering whether there is a sufcient number of nodes on the street to allow packet forwarding to the next junction.47position-base routing

47OutlinePart IVANET VANETPart IIGeographic Routing in City ScenariosPart IIIConclusions and Future work4848ConclusionVANETGeographic RoutingPacket49Future workVANET Routing

50Reference[1] C. Lochert, M. Mauve, H. Fussler, and H. Hartenstein, " GeographicRouting in City Scenarios, " ACM SIGMOBILE Mobile Computing andCommunications Review, Volume 9, Number 1, pp. 69-72, 2005.

[2] YUN-WEI LIN, YUH-SHYAN CHEN, SING-LING LEE, "Routing Protocols in Vehicular Ah Hoc Networks: A Survey and Future Perspectives", Journal of Information Science and Engineering, 2009.

[3],,, 2009

[4],,, 2007

[5] http://oasis.csie.ntu.edu.tw/2009_fall_network/slides/44 , VANET

[6] http://wmn.csie.ntpu.edu.tw/Telematic/97/971219/data/yschen.pdf , Routing and Mobility in VANETs51Q&AThanks for your attention!52