Embed Size (px)
Citation preview
An Information Model for Geographic Greedy Forwarding in Wireless Ad-Hoc Sensor Networks
Zhen JiangComputer Science Department
West Chester University
Junchao Ma, Wei LouDepartment of Computing
The Hong Kong Polytechnic University
Jie WuDepartment of Computer Sci. & Eng.
Florida Atlantic University
Infocom 2008
Outline
Introductions Related works Safety Model For LGF Routing Safety -Information-Based LGF Routing
(SLFG) Experimental Results Conclusions
Introductions
Geographic greedy forwarding routing is the most promising routing scheme in Wireless Ad-hoc Sensor Networks.
An important challenge often faced in geographic greedy forwarding in WASNs is the “local minimum phenomenon (Dead end)”.
Introductions
To mitigate the local minimum issue, GFG,GPSR and GOAFR are currently the most popular methods.
However, without enough shape information of the holes, such a routing may use a long detour path in the perimeter routing.
Introductions – goal
In this paper, the authors propose a simple and efficient method to achieve a shorter path.
Related works - Geographic greedy forwarding (GF)
B. Karp and H. Kung, “GPSR: Greedy perimeter stateless routing for wireless sensor networks,” Proc. of the 6th Annual ACM/IEEE International Conference on Mobile Computing and Networking (ACM/IEEE MOBICOM’00), August 2000, pp. 243-254.
Source
Destination
Related works - Limited geographic greedy forwarding (LGF)
Source
DestinationQuadrant I(Northeast)
Quadrant IV(Southeast)
Quadrant II(Northwest)
Quadrant III(Southwest)
Related works - BOUNDHOLE
Q. Fang, J. Gao, and L. Guibas, “Locating and bypassing routing holes in sensor networks,” Proc. of the 23rd Annual Joint Conference of the IEEE Computer and Communications Societies (IEEE INFOCOM’04), 2004, pp. 2458-2468.
Source
Destination
Boundary
Safety Model For LGF Routing -assumption
Each node has its location information. Sources are aware of the location of the
destination. All sensor has the same communication
range Each node has four forwarding zone. The system is rounded based
Safety -Information-Based LGF Routing (SLGF)
Unsafe Node
Safe Node
Source
Destination
Unsafe Area
Safety Model For LGF Routing –compare with BOUNDHOLE
BOUNDHOLE needs boundaries to encircled the hole and there are many unnecessary nodes in a boundary.
A boundary may be concave ,but the shape of the unsafe are has been optimized to a rectangle in a local view of each unsafe node.
Each unsafe node only stores the location of the opposite corner of rectangle
Safety model don’t need to calculate to identify the boundary.
Safety Model For LGF Routing
Quadrant I(NorthEast)
Quadrant IV(SouthEast)
Quadrant II(NorthWest)
Quadrant III(SouthWest)
u1(NE,NW,SW,SE)
u1
Safety Model For LGF Routing
u1(s,s,s,s)
u1
At the beginning, all forwarding regions are labeled as safe.
u2(s,s,s,s)u3(s,s,s,s)
u2
u3
u4
u4(s,s,s,s)
Safety Model For LGF Routing
u1(s,s,s,s)
u1
Each node starts labeling process
u2(s,s,s,s)u3(s,s,s,s)
u2
u3
u4
u4(s,s,s,s)u4(u,s,s,s)
u3(u,s,s,s)
u2(u,s,s,s)u1(u,s,s,s)
u5(s,s,s,s)
Safety Model For LGF Routing
Each unsafe node would estimated its unsafe area.
Unsafe Area
u1
u2
Safety Model For LGF Routing
Source
Destination
Unsafe Node
Proof in contrapositive formIf a greedy forwarding path exists, we can find an unsafe node uj that its successor uj+1 is safe.
uj
uj+1
Safety -Information-Based LGF Routing (SLGF)
Unsafe Node
Safe Node
Source
Destination
Safety -Information-Based LGF Routing (SLGF) -Source or destination inside unsafe area
The SLGF scheme will ignore unsafe node to avoid local minimum.
Source
Destination
Destination
Source
?
?
Safety -Information-Based LGF Routing – destination inside unsafe area
Destination
Source
Check if D is inside its unsafe area
D is inside the area. Forward the packet and discard safety information.
Safety -Information-Based LGF Routing -source inside unsafe area
The quickest way to leave such an unsafe area is to route in the opposite direction to d
Source
Destination
Experimental Results
Simulator: built in c++ Field : 200m x 200m
Uniform deployment (IA)
(Hole is very small) Random deployment (FA)
(Hole is larger than Uniform) The transmission radius of a node is 20m Number of nodes 400 to 800 in incensement of 50
Experimental Results - construction process under different information models
Boundary of BOUNDHOLE
Boundary of Safety Model for type I
Both BOUNDHOLE & Safety Model
Experimental Results
Experimental Results
Experimental Results
Experimental Results
Experimental Results
Experimental Results
Experimental Results
Conclusions
This paper is the first attempt to find the balance of the tradeoff between routing adaptivity and information mo
del cost while pursuing better routing performance in WASNs.
The authors proposed a easy and quick construction model
End
