MDBG Tzu-Tung Liao 1 OUTLINE I. Introduction MANET VANET II. - PowerPoint PPT Presentation

A ROUTING METHOD OF VANET MDBG Tzu-Tung Liao 1

OUTLINE  I. Introduction  MANET  VANET  II. Routing Protocols in VANET  GSR  AODV  III. MOVING DIRECTION BASED GREEDY(MDBG)  IV. MDBG Routing Algorithm  V. Comparisons & Simulations  VI. Conclusion.  VII. Q&A  VIII. Reference 2

INTRODUCTION  VANET(Vehicular Ad Hoc Network) is a kind of MANET  MANET  Infrastructure less  Hop-by-hop, must forward traffic unrelated to its own use.  Dynamic Topology  VANET  High moving speed  Directional  Wide range coverage  High Dynamic Topology  Connection hold shortly 3

MANET  Types of MANET:  Vehicular Ad Hoc Networks (VANETs) and Intelligent vehicular ad hoc networks (InVANETs)  Internet Based Mobile Ad hoc Networks (iMANET)  Non-directional move  Mobility devices connect to each others or internet. 4

VANET  Non-directional, but constrained by roads.  Applications: 1. Vehicle-to-roadside communications 2. Inter-vehicle communications 3. Emergency event. 5

MANET V.S. VANET Param ameter ers MANET VANET Cost of production Cheap Expensive 1. 1. Change in n/w topology Slow Frequent and very fast 2. 2. Mobility Low High 3. 3. Node density Sparse Dense and frequently variable 4. 4. Bandwidth Hundred kps Thousand kps 5. 5. Range Up to100m Up to 500m 6. 6. Node Lifetime Depends on power resource Depend on lifetime of vehicle 7. 7. Multi hop routing Available Weakly available 8. 8. Reliability Medium High 9. 9. Moving pattern of nodes Random Regular 10. Addressing scheme Attribute based Location based 11. Position acquisition Using ultrasonic Using GPS,RADAR 12. 6

ROUTING PROTOCOLS IN VANET  The routing protocols contains two major categories of topology-based and position-based routing. 7

GSR  Its routing table contains all destinations, the topology contains all timestamp that each nodes update, the next hop to destination, the number of nodes in the shortest path, and the sequence number identify the last updated.  The shortest path using a well known Dijkstra’s Algorithm.  Each nodes must know all destinations and construct a network topology.  When a node moved, it sends to all neighbors to update table only. That is avoid flooding problem.  Topology table is updated by neighbors after topology changed. 8

GSR(CONT.) Neighbor MH2 MH6 Destination Sequence Distance Next Hop MH4 1256953732 0 MH4 MH1 1256962994 2 MH2 MH2 1256954512 1 MH2 MH3 1256963211 2 MH2 MH5 1256963140 2 MH6 MH6 1256954651 1 MH6 MH7 1256963178 2 MH6 MH8 1256964012 3 MH6 9

GSR(CONT.) Neighbor MH2 MH6 Destination Sequence Distance Next Hop MH4 1256953732 0 MH4 MH1 1256966311 3 MH6 MH2 1256954512 1 MH2 MH3 1256963211 2 MH2 MH5 1256965991 2 MH6 MH6 1256965113 1 MH6 MH7 1256965976 2 MH6 MH8 1256966277 3 MH6 10

AODV  AODV is extended by DSR.  Establish connection when a data want to send.  When node in path is loss, reinitialize routing process.  Different between AODV and DSR:  DSR collects all nodes along the path. packets contains larger head when more nodes in path.  AODV improves it. Only the destination transmit back to source with the path nodes. 11

AODV(CONT.) Searching destination node 14 12

AODV (CONT.) Link 8-to-10 is broken 13

MOVING DIRECTION BASED GREEDY MDBG  Based on the moving direction  Used to enhance routing decision in packet delivery by finding a stable path while the source vehicle has packets to send to the target vehicle.  MDBG uses three types of control messages to assist in packet delivery. 14

MOVING DIRECTION BASED GREEDY ROUTING ALGORITHM  A. Basic Definitions and Environment Assumptions  each vehicle is equipped with an IEEE 802.11 wireless network card and a GPS module.  The network communication is assumed to be V2V(Vehicle to Vehicle) communication.  Traffic lights are also assumed to be located at each road intersection.  Moving direction define five possible moving directions for each vehicle: north, east, south, west and none. 15

MOVING DIRECTION BASED GREEDY (MDBG) ROUTING ALGORITHM  B. Three types of Control Messages  Hello message  Destination REQuest (DREQ) message  Destination REPly (DREP) message 16

FIVE POSSIBLE MOVING DIRECTIONS Definition of moving directions 17

MOVING DIRECTION BASED GREEDY (MDBG) ROUTING ALGORITHM 18

MOVING DIRECTION BASED GREEDY (MDBG) ROUTING ALGORITHM C. Selection of Next Hop - Same direction of reference: - Opposite to direction of reference: 19

MOVING DIRECTION BASED GREEDY (MDBG) ROUTING ALGORITHM C. Selection of Next Hop (cont.) The transmission range of vehicle A The upper bound of vehicle B A The lower bound of vehicle B B 20

MOVING DIRECTION BASED GREEDY (MDBG) ROUTING ALGORITHM  Three sets of “priority of neighbor vehicles”  Set 1 defines the priorities of neighbor vehicles when reference point velocity is 0.  Set 2 defines the priorities of neighbor vehicles whose moving directions are opposite to reference point direction.  Set 3 defines the priorities of neighbor vehicles when no forwarding vehicles are moving on the same direction. 21

CASE 1  Set 1: reference point (A) velocity is 0.  Forwarding vehicle A stops at the traffic light of an intersection. 22

CASE 2  Set 2: Opposite to reference point(A, B) direction.  Neighbor vehicles (C, D, E, F) stop at the traffic light. 23

CASE 3  Set 3: Moving on the same direction.  Reference point and neighbor vehicles have the same moving directions. 24

CASE 4  Worst case: All Vehicles are opposite to reference point(A) direction.  No neighbor vehicles move at the same direction as the reference point. 25

MOVING DIRECTION BASED GREEDY (MDBG) ROUTING ALGORITHM  D. Path Broken Repair Strategy and Routing Loop Detection 26

MOVING DIRECTION BASED GREEDY (MDBG) ROUTING ALGORITHM  D. Path Broken Repair Strategy and Routing Loop Detection (cont.) 27

COMPARISON OF MDBG, AODV, DSR 28

SIMULATIONS-COMPARISONS OF PACKET DELIVERY RATIO 29

SIMULATIONS-COMPARISONS OF THROUGHPUT. 30

SIMULATIONS-COMPARISONS OF AVERAGE END-TO-END DELAY. 31

SIMULATIONS RESULTS  Higher vehicle density can improve packet delivery ratio more.  Higher vehicle density results in higher throughput.  Higher vehicle density can reduce more number of broken links and more end-to-end delay.  When the vehicle density becomes lower, the vehicle velocity becomes higher and there are fewer intermediate vehicles to select.  The routing path is broken more frequently in lower vehicle density. 32

COMPARISON OF VANET ROUTING PROTOCOLS 33

CONCLUSION  MDBG is used to enhance routing decision in packet delivery.  MDBG algorithm is based on the geographical information collected by GPS.  MDBG algorithm is proposed to leverage the problem while source vehicle and target vehicle move far apart in opposite directions.  MDBG outperforms both AODV and DSR in packet arrival rate, throughput and average end-to-end delay. 34

 Q&A 35

REFFERENCE  Moving Direction Based Greedy Routing Algorithm for VANET/Print ISBN: 978-1-4244-7639-8  Padmini Misra , “Routing Protocols for Ad Hoc Mobile Wireless Networks”, http://www.cse.wustl.edu/~jain/cis788- 99/ftp/adhoc_routing/  Kevin C. Lee, Uichin Lee, Mario Gerla, "Survey of Routing Protocols in Vehicular Ad Hoc Networks“  http://www.scribd.com/doc/34832829/A-Comparative-study- of-MANET-and-VANET-Environment 36