Context Assisted Routing Protocols for InterVehicle Wireless Communication

1
Context Assisted Routing Protocols for
Inter-Vehicle Wireless Communication

• V. Dumitrescu and J. Guo
• Presented by Imranul Hoque

2
Contribution

• Authors Claim
• Network Partitioning Method
• Context Assisted Routing Protocol

3
Motivation
Partitioning
Destination
Source
4
Partitioning Method!!

• Assumptions
• Vehicles know their coordinate through GPS
• Static traffic info are stored on-board
• Real-time dynamic traffic info is gathered
  through IVC
• Push data
• Non-critical data broadcast to all vehicles in
  the region
• Critical data broadcast to all vehicles
  approaching the region
• Pull data
• Vehicles inquire for region specific data
• Messages GET_LCL_CTX, GET_RMT_CTX, SENS_CTX,
  SND_LCL_CTX, RE_CTX

5
Context Assisted Routing

• Spatial Model
• Predictive Location Service
• CAR Algorithm

6
Spatial Model
7
Spatial Model Graph
Fastest Route Highest Traffic Density Shortest
Route
Edges are weighted
Layered format of the spatial model can be used
8
Predictive Location Service

• PLS keeps track of node locations
• Locations becomes obsolete
• Frequent broadcast is a solution high overhead
• PLS is the solution predicts node location

9
Predictive Location Service (2)
Broadcast
10
Context Assisted Routing

• S wants to route a packet to D
• S gets coordinate from GPS
• S knows Ds coordinate fromPLS
• S knows the Spatial ModelGraph
• S locates itself and D on theSMG
• S calculates shortest path toD on SMG
• S does Greedy Forwarding to A (A retention cache
  canbe used if a suitable nodeis not found)

Problems?
11
Evaluation

• NS2 simulation with CMU wireless extension
• Compare CAR, CARC, GPSR
• Metrics
• Packet Delivery Ratio
• Packet Delivery Delay
• Average Hop Count

12
Packet Delivery Ration
Retention cache improves performance
GPSR can switch to perimeter mode
13
Packet Delivery Delay
Retention cache
Perimeter mode in GPSR
14
Conclusion

• Drawbacks
• Fixed destination
• Assumes that any intermediate vehicle will go to
  the destination
• Not very much novel