Top Banner
Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya
19

Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Mar 27, 2015

Download

Documents

Ashton Parks
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Low Overhead With Speed Aware Routing (LOWSAR) in VANETs

By Kannikar Siriwong Na Ayutaya

Page 2: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Outline• Problem• Routing Mechanism• Related Works• Objective• Contention-based Routing (CBR) Algorithm• Motivation• LOWSAR Algorithm• Results• Conclusion and Future works

Page 3: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Why need routing for VANETs?

• Reasons: High mobility and frequent network disconnection and merging

• Result: Topology-based routings in MANETs are NOT suitable for VANETs

• Solutions: Position-based routing and Contention-based routing

Page 4: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

VANETs Routing Mechanism

• Beaconing: periodically exchange location message between vehicles

• Location service: process of searching for unknown destination location

• Forwarding: transmitting packets to destination (unicast, broadcast, anycast, scan)

Page 5: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Related Works

• Position-based Routing (PBR)– Neighbor positions

obtained by beaconing

– Routing decision is done locally by one node at a time

• Contention-based Routing (CBR)– Routing decision is

done in distributed manner without beaconing

Page 6: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Related Works

• Position-based Routing (PBR)

• Contention-based Routing (CBR)

1

2

43 1

2

43

Page 7: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Related Works (Pros & Cons)• PBR

– Outdated neighbor positions

– High routing decision computational complexity

– Increase message exchanging overhead

– Enhance packet collision

– Eliminate packet redundancy

• CBR– Eliminate beaconing

overhead during routing decision

– Create possibility of packet redundancy

Page 8: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Objective

• Extend contention-based routing (CBR) to account for speed of vehicles

• Propose LOWSAR algorithm to speed up data delivery delay

Page 9: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Basic CBR Algorithm (Terminology)

• T = constant bias clock delay• r = transmission range

• Dmn = distance from nodem to noden

• d = bias clock delay• W = ratio of difference of distance

and r

Page 10: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

1

3

5

D15

D15

D35

r

D15 – D35

Basic CBR Algorithm

W = (D15 – D35)/r ≤ 1 d = T(1 – W)

Page 11: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

D15Basic CBR Algorithm

d = T

1

3

45

6

2

d < Td > T

7

W = (D17 – Di7)r, i = 2,…,6 d = T(1 – W)

Page 12: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

12

4

3

5

D15

D15

D35

r

D15 – D35

D25

D15 – D25 D45

D15 – D45 < 0

d = T(1-(D15 – D35)/r)

d = T(1-(D15 – D 15)/r) = T

d = T(1-(D15 – D25)/r)

d = T(1-(D15 – D45)/r) > T

Basic CBR Algorithm

Page 13: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

B

VAt

VBt

VCt

Problem: Location Dominated Forwarding

C

A

Page 14: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

A

BC

VA > 0

VC = 0

Problem: Speed Dominated Forwarding

Page 15: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

LOWSAR Algorithm

• V = vicinity of a vehicle• D = distance from a node to destination

d = min{ T(1 – W), T(1 – W)/V, T( D/r - 1)}

Page 16: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Preliminary ResultsDelivery Delay Performance of LOWSAR and CBR

0

0.5

1

1.5

2

2.5

25 45 65

Speed Limits (mph)

End

-to-

End

Del

ays

(sec

)

LOWSAR

CBR

Page 17: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Conclusion and Future Works

• Under different speed limits, LOWSAR outperforms CBR in terms of delivery delay

• Explore effects of other parameters on delivery delay – Number of source nodes– Data rate– Number of vehicles (traffic density)

Page 18: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.

Conclusion and Future Works

• Investigate on other performance metrics– Average number of hops to a destination– Packet delivery ratio

• Compare these performance with other compatible routing algorithms

Page 19: Low Overhead With Speed Aware Routing (LOWSAR) in VANETs By Kannikar Siriwong Na Ayutaya.