Vehicular Communication and Optimal Cooperative
Positioning
The Fully Networked Car
Geneva, 3-4 March 2010
Asghar
Tabatabaei Balaei
University of New South
Wales
1
Outline
o DSRC
o How does GNSS work?
o Why is GNSS not enough?
o What is cooperative positioning?
o How does DSRC help?
o Effect of network parameters on positioning
performance
o Precise position and reliable Communication
The Fully Networked Car
Geneva, 3-4 March 2010
2
Dedicated Short Range Communication
(DSRC)
o High-speed, short-range, low-latency
wireless communications between vehicles
o IEEE 802.11p standard for wireless access in
vehicular environments
— Rapid connection establishment and network acquisition
o System Components
− onboard units (OBU)
− Road side units (RSU)
The Fully Networked Car
Geneva, 3-4 March 2010
3
How does GNSS work?
•Multilateration
•TOA
•At least four satellites with atomic clocks
•Global coverage
•Unlimited number of users
GNSS Signal
Environmental
noise
The Fully Networked Car
Geneva, 3-4 March 2010
4
Why is GNSS not enough?
GPS
RF Interference
The Fully Networked Car
Geneva, 3-4 March 2010
5
Cooperative Positioning
The Fully Networked Car
Geneva, 3-4 March 2010
6
How dose DSRC help?
The Fully Networked Car
Geneva, 3-4 March 2010
7
How Dose DSRC help?
The Fully Networked Car
Geneva, 3-4 March 2010
8
Effect of network parameters on positioning
performance
16
PZ = 8
PZ = 256
PZ = 512
PZ = 1024
Reception per node per interval
14
12
10
8
6
4
2
0
0
20
40
60
80
Maximum possible reception per node per interval
The Fully Networked Car
Geneva, 3-4 March 2010
100
9
Precise position and reliable Communication
14
10
interval =.1s, PS = 1024
interval =1s, PS = 1024
interval =1s, PS = 512
interval =1s, PS = 1024
9
12
10
CRLB
CRLB
8
8
7
6
5
6
4
4
0
20
40
60
3
0
80
20
40
Node number
Node number
14
13
interval =.1s, PS = 1024
interval =.1s, PS = 512
12
CRLB
11
10
9
8
7
The Fully Networked Car
Geneva, 3-4 March 2010
6
0
20
40
Node number
60
80
60
80
10
Summary
o Cooperative Positioning is needed to
improve the positioning accuracy in the
vehicular environment
o Communication constraints affect the level
of accuracy that we can get from
cooperative positioning
The Fully Networked Car
Geneva, 3-4 March 2010
11