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Geographic Routing in Clustered Multi-layer Vehicular Ad Hoc Networks for Load Balancing Purposes. Di Wu 03/03/2011. VANET: Vehicular Ad Hoc Networks. Integrate ad hoc network, WLAN and cellular technology, etc. Achieve intelligent inter-vehicle communications and improve - PowerPoint PPT Presentation
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Di Wu03/03/2011
Geographic Routing in Clustered Multi-layer Vehicular Ad Hoc Networks for
Load Balancing Purposes
VANET: Vehicular Ad Hoc Networks Integrate ad hoc network, WLAN
and cellular technology, etc. Achieve intelligent inter-vehicle
communications and improve road traffic safety and efficiency. Three categories:
pure cellular/WLAN, pure ad hoc, and hybrid.
WMN: Wireless Mesh Networks Self-organized and self-configured WMN
Mesh routers: minimal mobility, backbone Mesh clients: stationary or mobile Integration with other networks: gateway and bridging in mesh routers.
Three categories: Infrastructure/Backbone WMNs, Client WMNs, Hybrid WMNs.
VANET differs from MANET High mobility, rapid topology change, various environments
MANET Routing in VANET Break very frequently Overhead increases: route repairs Low delivery ratios High transmission delays.
Internet
Wireless Mesh Clients
backbone
Mesh Router
GGLR: Geographic Greedy and Load-Balance Routing Regionalized and hierarchical VANET
The AR (Area Role) node: the backbone A vehicle node can communicate with AR node and other vehicles. Enhances the stability of the network Facilitates network load balancing
Forwarding set Two-hop neighbor information table Broadcast HELLO message:
source node's ID forwarder node's ID location of each node.
Set TTL to be 2: number of HELLO messages transmitted After sending a message, TTL minus 1. When the TTL equals 0, stop forward
The nearest node from the destination is chosen from the table, Hidden Problem
After receiving a new packet, the node checks member IDs of the forwarder’s forwarding set. The same node is removed form the node’s forwarding set.
AR AR
AR AR
INTERNET
A CB
GGLR: Geographic Greedy and Load-Balance Routing
Load balancing on ARBUSY: data cache reaches a thresholdFREE: not under congestionPeriodically broadcast FREE/BUSY to local vehicles.
Bypassing mechanism on vehicle When the AR is busy, vehicle will bypass it and search for another suitable AR. In this way, the AR node which is busy will avoid to fall into a congestion state.
S
DA A’
AR1 (Busy) AR2
GGLR: Geographic Greedy and Load-Balance Routing Greedy scheme used in inter-vehicle routing
When a Local Max happens, the data is sent to the destination in the help of local AR.
Local Max: if no neighbor is closer to the destination than the node itself. If the local AR is in congestion at the same time, store-carry-forw
ard routing will be used. Store, Carry and Forward
Buffer and carry the packet when no routesForward the packet to the nodes moves into the vicinity which ca
n help packet deliveryGPS service could provide the location and velocity information
on the road. Help to choose next-hop node.
S
3
2
D
14
S
1
34
D
2 S
3
1
4
D
2
t1 t2 t3
Performance Evaluation
Simulator: NCTUns 6.0: Supports VANET simulation Simulation Setting:
Area Size 600m*600m
Road Structure Two Lanes
MAC 802.11 DCF
Communication Range
100 m
Packet Type UDP
Packet Size 1400 Bytes
Moving Speed 10 m/s
Simulation Time
150 s
End to end transmission delay
Successful packet transmission ratio
End to End Del ay
00. 10. 20. 30. 40. 50. 60. 70. 8
5 10 15 20 25 30 35 40 45 50Number of Vehi cl es
Dela
y (S
)
GGLRGSRDSDV
Sended Packets/ Recei ved Packets
0
0. 5
1
1. 5
2
2. 5
5 10 15 20 25 30 35 40 45 50Number of Vehi cl es
Deli
very
Fra
ctio
n
DSDVGSRGGLR
Conclusion Clustered multi-layer VANET based on WMN infrastructure is an eff
ective hybrid networking to provide quality of service in high dynamic VANET communication scenarios. The hierarchical structure not only enhances the stability of the network topology, reduces the amount of redundant data and increases the network scalability, but also expands a scope of network services.
The GGLR protocol uses location information and forwarding set to better deal with data routing in highly dynamic topology. The algorithm provides better network load balancing solution by node congestion detection, AR-assisted forwarding, and vehicle bypassing mechanism.
GGLR presents stable routing and load balancing in hybrid VANET. It could be used in reliability and real-time oriented services.
Q&A
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