1. CS541 Advanced Networking 1 Vehicular Ad Hoc Networks (VANETs) Neil Tang 2/4/2009

2. CS541 Advanced Networking 2 Outline  Network Architecture  Characteristics  Applications  Major Concerns  802.11p  Network Layer Challenges  Mobility Model

3. CS541 Advanced Networking 3 Network Architecture

4. CS541 Advanced Networking 4 Characteristics  Multihop wireless network  Mobile nodes with movements restricted by roadways  Rich resources: power, memory, processing capabilities.  Every node is aware of its location, speed and moving direction.

5. CS541 Advanced Networking 5 Applications  Safety-related information dissemination  Internet access for passengers

6. CS541 Advanced Networking 6 Major Concerns  Location-related broadcasting/multicasting support  QoS support: reliability and delay  Scalability  Cooperation  Security

7. CS541 Advanced Networking 7 802.11-based MAC Layer- 802.11p  5.9GHz licensed spectrum band  High bandwidth  Ad-hoc mode (hidden terminal problem)  Short transmission range  Poor mobility support

8. CS541 Advanced Networking 8 Network Layer Challenges  Traditional ad hoc routing VS. store-and-forward (stateless) routing  Location-based unicast routing: location is known.  Geocast routing: Location-related broadcast and multicast routing  QoS support: reliability and delay  Mobility prediction: Movements are restricted and mobility parameters are known.  Routing in hybrid wireless networks (fixed roadside access points + mobile node)

9. CS541 Advanced Networking 9 Mobility Model  The well-known random waypoint model is not suitable for VANETs.  A mobility model needs to take into account the special movement properties: Manhatten model and city section model