1 TBD: Trajectory-Based Data Forwarding for Light-Traffic Vehicular Networks IEEE ICDCS’09, Montreal, Quebec, Canada Jaehoon Jeong, Shuo Gu, Yu Gu, Tian He and David Du Computer Science and Engineering University of Minnesota {jjeong,sguo,yugu,tianhe,du}@cs.umn.edu June 23rd, 2009
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1
TBD: Trajectory-Based Data Forwardingfor Light-Traffic Vehicular Networks
IEEE ICDCS’09, Montreal, Quebec, Canada
Jaehoon Jeong, Shuo Gu, Yu Gu, Tian He and David DuComputer Science and Engineering
University of Minnesota{jjeong,sguo,yugu,tianhe,du}@cs.umn.edu
June 23rd, 2009
Motivation2
The vehicular networking is getting a hot research topic. Internet Access, Driving Safety, Data Dissemination, etc.
The environments for the vehicular networks Every vehicle has a DSRC device for wireless
communication. Every vehicle has a GPS-based navigation system for
driving information. The Internet Access Points (APs)
are sparsely deployed in road networks.
The objective in this paper The vehicles can deliver their packets to APs through the
multi-hop forwarding with the help of other vehicles.
Problem Definition3
Next hop?
Carrier-1’sMoving
Trajectory
Carrier-2’sMoving
Trajectory
Light-Traffic Road Network
Forwarding Path
Delay-1
Delay-2
Delay-1 < Delay-2
Problem Definition4
Road Network with Unbalanced Traffic Density
Light Traffic Path
Heavy Traffic Path
Heavy T
raffic PathNext hop?
Forwarding Path
Delay-1
Delay-2
Delay-1 > Delay-2
Contribution and Challenges
5
Contribution Data forwarding based on Vehicle Trajectory
With vehicle trajectory, TBD outperforms the existing scheme (VADD, Infocom’06) only using vehicular traffic density.
Challenges A more accurate link delay model than VADD’s
Mathematical model for the link delay
End-to-End delay model based on vehicle trajectory E2E delay modeling based on (i) vehicular traffic
density and (ii) individual vehicle trajectory
v
Link Delay Model6
Objective To compute the expected link delay over a one-way road
segment.
Road Segment for Link Delay Model Given the vehicle arrival rate and the vehicle speed ,
How to compute the Forwarding Distance ?
fl
v
Forwarding Distance for Vehicle Arrivals
7
Forwarding Distance over Time Forwarding
Distance
)Distance Forwarding(fl
Rnndist ),( 01
Vehicle arrives
at time .
1kn1kt
vRttdist /),( 01
Forwarding Distance for Vehicle Arrivals
8
Forwarding Distance
vRT
Tvl
h
k
hhf
/ where1
vRttdist /),( 01
Forwarding Distance
vRttdistT /),( 010
Link Delay Model Comparison between VADD and TBD9
VADD Link Delay Model Given the vehicle arrival rate and the vehicle speed ,
the forwarding distance is the sum of the network components.
This model is inaccurate since it misses the following fact Only the first network component can be used for data forwarding.
Performance Comparison For Average Forwarding
Distance, TBD is much closerto the Simulation resultthan VADD.
v
E2E Delay Model10
Objective To compute the expected end-to-end delay
from a Vehicle to an Internet Access Point (AP).
Road Network Graph for Data Forwarding Given a vehicle’s
trajectory,how to compute the E2E delay? Since node1 and node2 have different trajectories, their E2E delays are different.
:Expected Delivery Delay (EDD)at Intersection 1 Where a packet is sent towards Intersection 2.