1. Vehicular Ad-hoc Networks
Joint Transport and
Communication Model for
Vehicular Ad-hoc Networks
Ivan Ho
Supervisors: Prof. Kin K. Leung and Prof. John W. Polak

2. Background Mobile Ad hoc NETwork (MANET):
A collection of wireless nodes communicating with each other in the absence of any infrastructure
Vehicular Ad hoc NETwork (VANET):
A subclass of MANET, which would perform crucial functions in road safety, detection of traffic accidents and reduction of traffic congestions.
However, driver behaviour, mobility constraints and high speeds create unique characteristics in VANET.
Mobile sensor network in MESSAGE
However, automotive ad hoc networks will behave in fundamentally different ways than the predominated models in MANET research…

3. Background Joint Transport and Communication Model:
to adequately capture spatial and temporal details and accuracy of vehicle propagation, link condition, node connectivity and network protocol operations
Key Question: How different characteristics of mobility affect the performance of wireless communication protocols?
To ensure the design feasibility of the mobile sensor network, modelling and design tools are needed…

4. Research Framework Protocol Mobility Model Spatial Dependence
Temporal Dependence
Relative Speed
Geographic Restrictions
Protocol
Throughput
Routing Overhead

5. Research Framework The focus of this research work Mobility Model
Spatial Dependence
Temporal Dependence
Relative Speed
Geographic Restrictions
Connectivity
Link Duration
Path Availability
Protocol
Throughput
Routing Overhead

6. Mobility Model
Random Waypoint Model
Reference Point Group Mobility (RPGM) Model
Freeway Mobility Model
Manhattan Mobility Model
Objective: To establish a general transport model that can
well describe the real-world environment
These models are insufficient to capture the major
characteristics of the real-world transport systems!
For instance, previous works show that the results obtained from different models vary widely and do not realistically represent vehicular traffic speeds, directions and trips. Moreover, none of them consider mobile nodes as scheduled transport systems (e.g. Bus, tube) other than private vehicles, and traffic delays caused by congestions and traffic control through traffic lights or stop signs are also neglected. Therefore, our first objective is to establish an arbitrary transport model that can well describe the real-world environment.
T. Camp, J. Boleng, V. Davies, "A Survey of Mobility Models for Ad Hoc Network Research," Wireless Communications & Mobile Computing, Vol. 2, No. 5, 2002.

7. Propagation Model
Shadowing,
attenuations of signal at obstacles
NLOS
LOS
Objective: To identify the propagation model that could accommodate the environment of vehicle networks
NLOS
In an urban environment, the signal may reach the receiver via non-line-of-sight (NLOS) propagation mechanisms, such as reflection, diffraction, and scattering.

8. Joint-Transport- Communication Model
What is the impact of the mobility model on the connectivity graph, which in turn influences the protocol performance?
e.g. Relationship between node density and connectivity
Node density
Connectivity
Degree of connectivity = F(node density, velocity, mobility pattern)

9. Simulators Area of Interest Traffic Model VisSim, Paramics, SUMO
GrooveNet
More sophisticated
NS-2, QualNet, Opnet
Communication Model
We are going to figure out which is the most efficient and cost effective way for achieving our goal.
More sophisticated
R. Mangharam, D. Weller, R. Rajkumar, P. Mudalige and F. Bai, "GrooveNet: A Hybrid Simulator for Vehicle-to-Vehicle Networks," V2VCOM, Jul 2006.

10. Summary
- Develop appropriate mobility and communication models
Communication connectivity among vehicles
Verify and optimize efficiency of vehicular ad hoc networks
Mobility Model
Spatial Dependence
Temporal Dependence
Relative Speed
Geographic Restrictions
Protocol
Throughput
Routing Overhead
Connectivity
Link Duration
Path Availability
The Joint Model acts as a framework for future VANET design - understand and exploit dynamics between vehicle movement and communication capability
- enable efficient design of vehicular ad hoc network for transport systems control/management

11. Q & A