A Traffic-light-based Reliable Routing Protocol for Urban VANETs 都會區車載隨意網路下基於紅綠燈之可靠繞徑技術

Copyright © 2012, [email protected]

A Traffic-light-based Reliable Routing Protocol for Urban VANETs

都會區車載隨意網路下基於紅綠燈之可靠繞徑技術指導教授：王國禎博士學生：張景喬

國立交通大學網路工程研究所行動計算與寬頻網路實驗室


Outlines

• Introduction• Background• Related work• Proposed Traffic-Light based Approach routing protocol• Simulation results• Conclusion• References


Introduction

• Vehicular ad hoc network is a high mobility wireless ad hoc network.

• Due to a high mobility in VANETs, wireless links would be disconnected frequently .

• Routing paths may be very unstable at high mobility wireless ad hoc network


Introduction (cont.)

• Topology changed frequently.

• Broken link causes throughput decreases, and packet delay increases.

• Highway safety, commercial advertisement, and Digital entertainment becomes popular issue recently.


Related work - DSR

• DSR (Dynamic Source Routing)• Cached routing information• Main process:

– Route discovery– Route maintenance

• Once node receives RREQ, if the node has not seen it before, it adds themselves to the route and forward them.

• If there is any broken link happens due to the network topology changes, source node can issue another ROUTE REQUEST to find a new route.


Related work - AODV

• AODV (Ad-hoc On-demand Distance Vector)• Source node broadcasts RREQ until the packets reach to

destination node or the intermediate nodes contain the route to the destination node.

• Once receiving RREQ packet, it replies back to the source by the route.

• Every node periodically broadcasts HELLO message to check a broken link.

• When a broken link is detected, RRER will be issued to the source node, then it issues new route discovery


Related work - CLA

• CLA (Connectionless approach) Routing -Adapt the topology effectively -Do not need to maintain nodes routing table -The nodes are included in the Virtual Cell can relay data packets


Related work - CLA

• Streets are divided into cells


Related work - CLA

• Concept of CLA


Proposed TLA routing

• TLA (Traffic Light based Approach) routing-When the vehicles stop at the red traffic lights, it is the best chance to forward the data between the vehicles.-Divide the network area into numbers of small “virtual area”.-Select a list of “Virtual Area” to be a route forwarding area between source and destination nodes.

Requirement:• GPS (Global Positioning System)• Digital Map• Sensor


Proposed TLA Routing

Virtual Area ID set up:• Virtual Area ID Builds on intersection.

Reasons:1. The intersection must have traffic lights.2. The red lights turn on means the

vehicles must stop at the intersection3. It is the best chance to relay the packet messages 4. Reliable and stable, increases the packet delivery ratio



• Virtual Area ID set up S

D

A101A201

A301

A102

A103

A104

A105

A202

A203

A204

A302

A303

A304

A205A2b05

A305



Route Discovery:• Source node floods the RREQ message.• RREQ packet contains Source ID, Destination ID,

Sequence number, and Area record. • Area record contains the order of area IDs.• When Intermediate nodes receive duplicated RREQ, it

attaches the current area ID into area record and forward it.



Route Discovery:• Hop count is not larger than that of the first received

RREQ.• The destination node receives the RREQ:

1. records current area ID 2. records current node’s direction3. sends RREP back via the chosen routes



Data transmission:• Source node sends data according to the Area Record.• Area record includes the whole area IDs which present a route.

Data packet header includes:Source IDDestination IDRoute recordCurrent area ID



Data transmission:• An algorithm for a node C receives a data packet from

node B:1. If C node is a destination node, stop transmitting data

packet.2. If C node is not in the area IDs of the route record, stop

transmitting data packet.3. Otherwise, C node is in the range of area IDs, then delay

T (for listening other nodes’ transmission), if no nodes are transmitting, then C node transmit the data packet.



Delay time of packet transmission

• Where α is a maximum delay constant in m seconds• SPDn is the speed of node n• Distn is the distance between node n and the node m’s virtual

area center.• R is the random number between minimum R to maximum

R.

RDistSPDDELAYn

nn





Data transmission



Data transmission


Evaluation Parameters

• Simulation Setting for GlomoSim [10]

Simulation Time 900sMobility Model VanetMobiSimTerrain Dimensions 1000*1000MAC Protocol 802.11Data Traffic Generation CBRPacket Size 512 ByteRadio Range 278m


Evaluation Parameters

• VanetMobiSim[9] Parameters for Road Layouts

22

Simulation Time 900sMax Traffic lights 30Terrain Size 1000m*1000mMin. Speed 1 m/s (3.6km/hr)Max. Speed 15 m/s (54km/hr)Nodes (vehicles) 30, 50, 100, 200Max. acceleration 0.6 m/s2

Normal deceleration 0.5 m/s2


Effect of Different Number of Nodes

30 50 100 2000

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


TLA(Proposed)CAM

Number of Nodes

Pack

et D

eliv

ery

Ratio



30 50 100 2000

20

40

60

80

100

120


TLA(Proposed)CAM

Number of Nodes

End-

to-E

nd D

elay

(ms)


Conclusion

• We propose a Traffic Light based routing protocol for urban VANETs.

• The proposed TLA improves the delivery ratio by 15% and the end-to-end delay by around 20ms

• Delivering packets to a node which are waiting for the red traffic light effectively improve the throughput (packet delivery ratio)

• Decrease the end-to-end delay by transmitting with stationary nodes


References

[1] X. Fei, et al., "Performance Study of Live Video Streaming Over Highway Vehicular Ad Hoc Networks," in Vehicular Technology Conference, 2007. VTC-2007 Fall. 2007 IEEE 66th, 2007, pp. 2121-2125.[2] M. K. Marina and S. R. Das, "On-demand multipath distance vector routing in ad hoc networks," in Network Protocols, 2001. Ninth International Conference on, 2001, pp. 14-23.[3] Lee, S.-J.; Gerla, M.;“Split Multipath Routing with Maximally Disjoint Paths in Ad hoc Networks” in IEEE International Conference on Volume: 10, Digital, 2001, pp.3201 – 3205[4] V. K. Goyal, "Multiple Description Coding: Compression Meets the Network," IEEE Signal Processing Magazine, vol. 18, no. 5, pp. 74–94, Sept. 2001.[5] T.Wiegand, G.J. Sullivan, G. Bjøntegaard, A.Luthra: Overview of the H.264/AVC Video Coding Standard. IEEE Transactions on Circuits and Systems for Video Technology, Vol. 13, No. 7, July 2003


References[6]A.H. Ho, Y.H. Ho, K.A. Hua. Connectionless approach to mobile ad hoc network in street environments, in: Proceedings of IEEE Intelligent Vehicles Symposium (IV 2005). Nevada, USA, 2005.[7]H. Fubler, J. Widmer, M. Kasemann, M. Mauve, H. Hartenstein,

Contention-based forwarding for mobile ad-hoc networks, Elsevier’s Ad-Hoc Networks 1 (4) (2003) 351–369.

[8] Y. Jiazi, et al., "Simulation and Performance Analysis of MP-OLSR for Mobile Ad Hoc Networks," in Wireless Communications and Networking Conference, 2008. WCNC 2008. IEEE, 2008, pp. 2235- 2240.[9] M. Fiore, J. Härri, F. Filali, and C. Bonnet, “Vehicular mobility simulation for VANETs,” in 40th Annual Simulation Symposium, March 2007, pp. 301-307.[10] X. Zeng, R. Bagrodia, and M. Gerla, “GloMoSim: A library for parallel simulation of large-scale wireless networks,” in 12th Workshop on Parallel and Distributed Simulations, May 1998, pp. 154-161.

Documents

A Traffic-light-based Reliable Routing Protocol for Urban VANETs 都會區車載隨意網路下基於紅綠燈之 可靠 繞徑技術

A Traffic-light-based Reliable Routing Protocol for Urban VANETs 都會區車載隨意網路下基於紅綠燈之可靠繞徑技術