1. Zhen Jiang Comp. Sci. Dept. West Chester University
An Information Model for Geographic Greedy Forwarding in Wireless Ad-Hoc Sensor Networks
Zhen Jiang
Comp. Sci. Dept.
West Chester University
Junchao Ma, Wei Lou
Dept. of Computing
The HK Polytechnic University
Jie Wu
Dept. of Computer Sci. & Eng.
Florida Atlantic University & NSF
9/19/2018
INFOCOM'08

2. Outline Introduction Our Approaches Experimental Results Conclusion
Future Work
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3. Goal An efficient path in wireless ad-hoc sensor networks (WASNs)
Fewer hops and detours
Faster data delivery
More energy conserved
destination
source
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4. Problem Local minimum phenomenon (void) Sparse deployment
Physical obstacles
Node failures
Communication jamming
Power exhaustion
Animus interference
block
void
stuck node
destination
source
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5. Idea Information helps routing to Predict the ‘void’ ahead
Make a slight turn early to sufficiently avoid being blocked
Non-detour routing, i.e., greedy forwarding without perimeter routing
Make a turn only if necessary
To keep the optimality of a straight forwarding
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6. Challenge 1 Identification of the affected area of a void
Relative to the positions of the source and the destination
destination
destination
source
destination
source
source
affected area
destination
affected area
Case 1
Case 2
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7. Challenge 2 Mutual impact of void areas
Global optimization achieved by neighborhood optimizations
No routing table, flooding, or broadcasting
Routing decision at each intermediate node
Neighbor information collection and distribution
destination
source
area of mutual impact
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8. Challenge 3 Unstructured WASNs
Hard to ensure whether the forwarding still achievable ahead
destination ?
source
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9. What kind of information and how to conduct a forecast?
Illustration
What kind of information and how to conduct a forecast?
No global information
New York (destination)
Information exchanged with next light
traffic prediction
West Chester (source)
light control related to travel destination
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10. Related Work “Dead end” model Boundary model
No optimization
Boundary model
No global optimization
Hull algorithm, or turning angle model
No consideration of the relative positions
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11. Our Approaches
Tradeoff between routing adaptivity and structure regularity
Safety information for such a forwarding
Information based forwarding (SLGF routing)
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12. Tradeoff LAR 1 LAR 2 A forwarding with infrastructure in WASNs LAR2:
Forwarding to a neighbor that is closer to the destination
We adopt LAR1
Forwarding limited in the so-called request zone
destination
destination
forwarding candidate
LAR 1
LAR 2
request zone
current node
current node
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13. Safety Information Inspired by the safety model in 2-D mesh networks
An unsafe area contains nodes that definitely causing routing detour.
Constructed by a labeling process via information exchanges among neighbors.
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14. Details of the Labeling Process
Unsafe node
A node without any neighbor in the request zone
A node without any safe neighbor in the request zone
Unsafe area
Connected unsafe nodes
Estimated as a rectangle at an unsafe node.
4 Different types of unsafe status
Due to 4 different types of request zones
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15. An Example of Type-I Safety Information
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16. SLGF Routing Four phases conducted in the order Enforced forwarding
Safe forwarding
Perimeter routing (for making a slight turn)
Retreating (in the opposite direction)
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17. Simulation To verify whether Forwarding routings
LAR1(-) + Safety Info. (-) + Info. based routing (+) is better than boundary info. based routing.
Forwarding routings
GF (LAR2 + boundary information)
LGF (LAR1)
SLGF (LAR1 + safety information)
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18. 9/19/2018
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19. Result Summary Cost Routing success Routing path
safety information < boundary information
Routing success
GF = LGF = SLGF
Routing path
LGF < GF << SLGF
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20. Conclusion Unicast routing but neighborcast information construction
Tradeoff between routing adaptivity and information model cost
Mutual impact of void areas
Better forwarding routing to achieve more straight paths
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21. Future Work
New balance point of the tradeoff between routing adaptivity and information model cost
More accurate information
Better forwarding routing to achieve more straight path
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22. Questions?
Thank you!
9/19/2018
INFOCOM'08