Road-Based Multipath Routing With Resilient Video Streaming for Urban VANETs

Copyright © 2011, [email protected]

Road-Based Multipath Routing With Resilient Video Streaming for Urban VANETs

指導教授：王國禎博士學生：鍾昆佑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

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Outline

• Introduction• Background• Design approach• Simulation and discussion• Conclusion • References

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Introduction

• It is commonly acknowledged that Vehicular Ad Hoc Networks (VANETs) are unsuited to support multimedia traffic.

• Wireless links would be broken frequently because of high mobility in VANET.

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Introduction

• In urban VANET , each vehicle moves in constrained areas independently.

• Due to the error-prone characteristic of wireless communication, routing packets over multiple hops results in packet loss and causes poor quality of reconstructed video at the receiver

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Introduction

• Ad-hoc on-demand distance vector(AODV) [1] and dynamic source routing(DSR) [2] are two most widely studied on-demand ad hoc routing protocol

• The traditional node-centric view of the route leads to frequent broken routes in the presence of VANETs’ high mobility as illustrated in Figure 1 [3]

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Introduction

6

S

N1

N2 D

S

N1

N2 D

(a) At time t

(b) At time t + a

Figure 1 Node-centric problem


Introduction

• One alternative approach is offered by geographical routing protocols, e.g., greedy–face–greedy (GFG) [4], greedy other adaptive face routing (GOAFR) [5]

• It can not always find the route to destination as illustrated in Figure 2

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Introduction

8

S

N1

N2 D

Dead end road

Figure 2 Geographical routing problem


Introduction

• There are many single path routings, which need new route discovery whenever a path breaks

• [6] has proofed multiple path can improve the packet delivery ratio if there is no interference.

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Introduction

• PA and PB are packet delivery ratio without interference for each single path

• Psin : Single path routing delivery ratio

• Pmulti : Multiple path routing delivery ratio

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Introduction

• Psin=Max{PA,PB} (1)

• Pmulti=1-(1-PA)(1-PB)=PA+PB-PAPB (2)

• PA ≤ 1 and PB ≤ 1 , PAPB ≤ Min{PA,PB} (3)

• Pmulti ≥ Max{PA,PB} ≥ Psin (4)

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Introduction

• Multiple path can classify two types : node-disjoint and link-disjoint

• [7] has proofed node-disjoint is better than link-disjoint on packet delivery ratio

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Introduction

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Introduction

• p ： probability of route broken

• Pi ： number of i common node

• Path1 has m nodes and Path2 has n nodes

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Introduction

• P0=p[Path1] x p[Path2]=(1-(1-p)m) x (1-(1-p)n) (4)

• P1=p[Path1] x p[Path2]=(1-(1-p)m-1) x (1-(1-p)n-1)+p (5)

• Because P1 - P0 ≥ 0 , so we can prove Pk ≥ Pk-1 ≥ … ≥ P0 by mathematical induction

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Introduction

• We propose a road-based multipath routing(RBMR) with resilient video streaming scheme that integrates flexible macroblock ordering (FMO) and multiple description coding (MDC)— Improve video streaming quality

— Recover lost packets with error resilience via FMO and MDC— Improve the reliability of routing paths

— Maintain a modified vehicle persistence score (VPS) [8] to determine the stability of a node

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Background

• Modified vehicle persistence score (VPS)– VPS table

• VPS table entry <ID, position, segment, direction, VPS>

– ID: the neighbor’s identifier– position: the GPS coordinate (x, y), which stands for the

neighbor’s position – segment : the neighbor is located– direction: the neighbor’s moving direction– VPS: the value used to select relay node

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Background

• VPS maintains– When vehicle received a HELLO message , it searched

its VPS table– If the neighbor’s ID can be found in the VPS table, the

vehicle increases neighbor's VPS by 1.– If identifier can not be found in the VPS table, the vehicle

adds the neighbor’s information to the VPS table, and initializes the neighbor’s VPS to 1.

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Background

• An example of VPS table

(a) VPS values are initialized when receiving a HELLO message

(b) VPS values are increased when receiving a HELLO message

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A

B

CD

E

F

ID VPSABCDE

11111

R A

B

CD

E

F

ID VPSABDEF

22221

R


Background

• Flexible Macroblock Ordering (FMO) [9]– One of error resilience techniques defined by the

H.264/AVC specifications– An image is divided into slice groups, and each slice

group can be divided into several slices, consisting of a sequence of macroblocks that belong to the same slice group

– The power of FMO depends on how the macroblocks are ordered

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Background

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Image

Slicegroup Slicegroup

Slice Slice Slice Slice

Mb Mb Mb Mb Mb Mb MbMb


Background

• FMO type[9]

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Background

• Multiple description coding (MDC) segments a single stream into n substreams which called descriptions.

• MDC is used to supply error resilience to media streams.

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Design approach - RBMR

• Four stages of the proposed road-based multipath routing (RBMR) scheme for resilient video streaming – Video encoding stage– Route discovery stage– Data transfer stage– Video decoding stage

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Design approach – RBMR

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Sender

Video encoding stage

Route discovery stage

Data transfer stage

Video decoding stage

The procedure of RBMR

Destination


RBMR – Video encoding stage

• Video encoding stage– Before a sender starts transmitting to a receiver, it

encodes the row video stream with FMO type 1, splitting the video streaming into multiple slices for error resilience at the receiver

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RBMR – Video encoding stage

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RBMR – Route discovery stage

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Start

Does the node receive the RREQ

at first time

Is the segment number of the node

recorded in the header

End

Yes

Yes

Are segment numbers the same

with previous received

Broadcast the RREQ Discard the RREQ

No

No

Yes

Add the segment number to the header

No



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• Block ID recorded in the RREQ header

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• RREP is sent by the reverse block ID

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RBMR – Data transfer stage

• Relay nodes selection– Select relay nodes from the VPS table according to the

data stored in the VPS table– Data used for selection

• segment: used to choose relay nodes which located in the next segment of the header.

• direction : used to choose relay nodes which moved toward the receiver.

• VPS: used to choose relay node which has the highest.

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RBMR – Data transfer stage

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RBMR– Video decoding phase

• Video decoding phase– After a receiver receives all packets transmitting from a

sender, it decodes and creates a reconstructed video stream

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Simulation and discussion

• Packet delivery ratio: the number of data packets successfully delivered to the receiver divided by the total number of data packets generated by the sender

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generated packetsdata of number Totalpacketsdata receivedly SuccessfulveryRatioPacketDeli


Simulation and discussion (cont.)

• Routing overhead: when we transfer a packet, how many control messages we need to send.

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• Simulation settings for NS2 [11]

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Parameter Value Transmission range 250 m MAC Protocol IEEE 802.11 Network area 1000 m x 1000 m Lane width 5 m Number of vehicles 30, 40, 50, 60, 70 Connection type CBR Packet size 1000 bytes Mobility model VanetMobiSim Simulation time 100 s



• Simulation settings for VanetMobiSim [4, 5]

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Parameter Value Terrain Dimension 1000 m x 1000 mMax. traffic lights 6 Time interval between traffic lights change

10 s

Number of Lanes 2 Nodes (vehicles) 30, 40, 50, 60, 70 Min. Speed 8.1m/s Max. Speed 16.9 m/s Length of vehicle 5 m Max. acceleration 0.6 m/s2

Normal deceleration 0.5 m/s2



• Delivery ratio under different numbers of vehicles

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• Routing overhead under different numbers of vehicles


Conclusion

• We propose road-based multipath routing for Urban VANETs

• The proposed RBMR improves the delivery ratio by 7% and control overhead by 30% compared with AOMDV

• • Simulation results show that the proposed RBMR

performs well in city environments

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References

1) H. Hartenstein and K. P. Laberteaux, "A tutorial survey on vehicular ad hoc networks," Communications Magazine, IEEE, vol. 46, pp. 164-171, 2008.

2) M.H. Wei, K.C. Wang, and I.L. Hsieh “A reliable routing scheme based on vehicle moving similarity for VANETs,” in Proc. IEEE TENCON, 2011.

3) S. Wenger, “H2.46/AVC over IP,” IEEE Trans. on Circuits and Syst. for Video Technol., vol. 13, no. 7, pp. 645-656, 2003.

4) N. Qadri, M. Altaf, M. Fleury, M. Ghanbari, and H. Sammak, "Robust Video Streaming over an Urban VANET," in Proc, International Conference on Wireless and Mobile Computing, Networking and Communications, 2009. WIMOB 2009. IEEE, 2009, pp. 429-434.

5) N. N. Qadri, M. Fleury, and M. Ghanbari, "Approaching P2P communication in a vehicular ad hoc network," in IEEE 34th Conference on Local Computer Networks, pp. 695-701 2009.

6) N. Qadri, M. Fleury, M. Altaf, B. R. Rofoee, and M. Ghanbari, "Resilient P2P multimedia exchange in a VANET," in Wireless Days (WD) , pp. 1-6, 2009 2nd IFIP, 2009.

7) N. N. Qadri, M. Fleury, M. Altaf, and M. Ghanbari, "Multi-source video streaming in a wireless vehicular ad hoc network," Communications, IET, vol. 4, pp. 1300-1311.

8) F. Soldo, C. Casetti, C.-F. Chiasserini, P. Chaparro, “Streaming Media Distribution in VANETs,” in Proc, Global Telecommunications Conference, pp. 1-6, 2008.

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References

9) W. Shu, P. Wang, A. Guo, X. Wang, F. Liu, “Enhanced GPSR using Neighbor-Awareness position Update and Beacon-assist Geographic Forwarding in vehicular ad hoc networks,” in proc, Intelligent Vehicles Symposium, pp. 1143-1147, 2009

10) J. Nzouonta, N. Rajgure, A. Guiling Wang, C. Borcea, “VANET Routing on City Roads Using Real-Time Vehicular Traffic Information ,” in Transactions Vehicular Technology pp. 3609 - 3626, 2009

11) “The network simulator (NS2),” [Online]. Available: http://www.isi.edu/nsnam/ns/.

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Road-Based Multipath Routing With Resilient Video Streaming for Urban VANETs