A Stable Routing Protocol to Support ITS Services in VANET Networks Tarik Taleb, Ehssan Sakhaee, Abbas Jamalipour, Kazuo Hashimoto, Nei Kato, Yoshiaki Nemoto Tohoku University, Japan University of Sydney, Australia IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, TVT 2007

Outline Introduction Proposed routing protocol Performance evaluation Conclusion

Introduction IVC (Intervehicle Communication) AB

Introduction RVC (Road-vehicle Communication) A B

VANET is constrained by predefined roads, speed limits, and traffic control mechanisms. VANET network is a special case of MANET. Introduction

Introduction - scenario A B IVC and RVC coexist.

Introduction - motivation A B EDC

A B EDC Link breakage Introduction - motivation

Increasing link duration. Reducing the number of link-breakage events. Introduction - Goal

Proposed routing protocol (ROMSGP) -Grouping of vehicles -Calculation of LET (Link expiration time) -ROMSGP (Receive on Most Stable Group-Path) -Link breakage

Proposed routing protocol (ROMSGP) A Source C DF Destination B

A Source C DF Destination B

S1S1 S2S2 S3S3 S4S4 Group 1Group 3 Group 4 Group 2 Grouping of vehicles A Unit vector S 1 =(1,0), S 2 =(0,1), S 3 =(-1,0), S 4 =(0,-1) V A =(v x,v y ) VA．SNVA．SN V A =(10,0) V A ． S 1 = 10 V A ． S 2 = 0 V A ． S 3 =-10 V A ． S 4 = 0 Max + + _ _

Proposed routing protocol (ROMSGP) S1S1 S2S2 S3S3 S4S4 Group 1Group 3 Group 4 Group 2 Grouping of vehicles B Unit vector S 1 =(1,0), S 2 =(0,1), S 3 =(-1,0), S 4 =(0,-1) V B =(v x,v y ) VB．SNVB．SN V B =(0,-15) V B ． S 1 = 0 V B ． S 2 = -15 V B ． S 3 = 0 V B ． S 4 = 15 Max + + _ _

Proposed routing protocol (ROMSGP) Calculation of LET( Link expiration time ) r : Transmission or line-of-sight range V: Velocity Ө: Velocity angle ӨiӨi ӨjӨj vjvj vivi (x j, y j ) (x i, y i ) r i j

Proposed routing protocol (ROMSGP) Calculation of LET Ө i =30 度 Ө j = 0 度 v j =20 m/s (0,0 )(5,0 ) 5 LET = 1.2 v i =10 m/s Ө i = 0 度 Ө j = 0 度 v j =20 m/s (0,0 ) (5,0 ) 5 v i =10 m/s LET = 5.5 j j i i

CNARequired Data Required Time LifetimeGroup ID RREQ packet format Cached node address is where the address of the forwarding vehicle stored. The Required Data field defines the requested data. The Required Time field defines the time needed for the data transmission. Lifetime field will determine the expiration parameters for the request packet. The Group ID field identifies the group to which the requesting vehicle belongs. Proposed routing protocol (ROMSGP)

CNARequired Data Required Time LifetimeGroup ID RREQ packet format Cached node address is where the address of the forwarding vehicle stored. The Required Data field defines the requested data. The Required Time field defines the time needed for the data transmission. Lifetime field will determine the expiration parameters for the request packet. The Group ID field identifies the group to which the requesting vehicle belongs. Proposed routing protocol (ROMSGP)

CNARequired Data Required Time LifetimeGroup ID RREQ packet format Cached node address is where the address of the forwarding vehicle stored. The Required Data field defines the requested data. The Required Time field defines the time needed for the data transmission. Lifetime field will determine the expiration parameters for the request packet. The Group ID field identifies the group to which the requesting vehicle belongs. Proposed routing protocol (ROMSGP)

CNARequired Data Required Time LifetimeGroup ID RREQ packet format Cached node address is where the address of the forwarding vehicle stored. The Required Data field defines the requested data. The Required Time field defines the time needed for the data transmission. Lifetime field will determine the expiration parameters for the request packet. The Group ID field identifies the group to which the requesting vehicle belongs. Proposed routing protocol (ROMSGP)

CNARequired Data Required Time LifetimeGroup ID RREQ packet format Cached node address is where the address of the forwarding vehicle stored. The Required Data field defines the requested data. The Required Time field defines the time needed for the data transmission. Lifetime field will determine the expiration parameters for the request packet. The Group ID field identifies the group to which the requesting vehicle belongs. Proposed routing protocol (ROMSGP)

CNARequired Data Mobility Information Bottleneck LET RREP packet format Each node inputs its mobility information into this field before forwarding the RREP packet. The Bottleneck LET field represents the shortest lived link on the path. Proposed routing protocol (ROMSGP)

CNARequired Data Mobility Information Bottleneck LET RREP packet format Each node inputs its mobility information into this field before forwarding the RREP packet. The Bottleneck LET field represents the shortest lived link on the path. Proposed routing protocol (ROMSGP)

A SC GD F I E B J RREQ packet format CNARequired Data Required Time LifetimeGroup ID

Proposed routing protocol (ROMSGP) A SC GD F I E B J CNARequired Data Mobility Information Bottleneck LET RREP packet format

–With alternative path Choose the alternative path, and sent the RERR packet to the source vehicle. –Without alternative path If the broken link is less than h hops from the source, a RERR message with the details of the broken link is sent to the source vehicle. The source vehicle then initiates a route discovery. A local route recovery procedure. Link breakage Proposed routing protocol (ROMSGP)

Link breakage with alternative path RERR Proposed routing protocol (ROMSGP) A SC GD F I E B J

SEDFAGBCI Link breakage with local recovery Broadcast two-hop recovery request Proposed routing protocol (ROMSGP) RREC

Performance evaluation Vehicles move along the roads until they reach intersections. Their probabilities of continuing straight, turning right, or turning left are set to 0.5, 0.25, and 0.25, respectively.

Performance evaluation

Conclusion The ROMSGP can increase link duration, reduce the number of link-breakage. The ROMSGP can provide good stability and maintain high throughput in VANET. Guaranteeing a stable and reliable routing mechanism over VANET.

Thank you!