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A Topology Control Approach to Using
Directional Antennas in Wireless Mesh
Networks
Umesh Kumar, Himanshu Gupta and Samir R. DasDepartment of Computer Science
State University of New York at Stony Brook
ICC 2006
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Outline Introduction Background and Problem formulation Algorithm Performance evaluation Conclusion
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Introduction Direction vs. Omni-direction
Spatial reuse The transmission range of direction antennas
are longer than one of omni-direction antennas Improving capacity
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Background and Problem formulation--Assumption The transmission range of direction
antenna : Rd The transmission range of omni-direction
antenna : Ro Rd/Ro = 2/tan(θ/2)
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Interference model The number of nodes are hear this
transmission
u ve
A
G
B
E
C
D
F
|Interfer(e)| =2
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Problem formulation k-direction antennas on each node
kθ < 360 max node degree is k Maximizing throughput
Minimizing interference Smaller interference caused path lengths
increasing
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Spanning Tree Algorithm Furer and Raghavachari’s algorithm
G=(V,E) Input : random spanning tree T=(V,E) Let S be the set of vertices having degree d or d-1
(d is the degree of T) Let T1,…,Tr be the subtrees comprising T-S If there is an edge between Ti and Tj, the edge is
inserted in T Output: minimum degree spanning tree T=(V,E)
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Using direction antenna A centralized algorithm Using k arcs of angle θ and radius Rd on
each node to cover all edges in E’
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Performance evaluation :Simulation environment
Simulator Qualnet
The number of node 100
Transmission range 70m
Network size 300 m2 or 500 m2
Average node degrees 5 or 13
Antenna beamwidth 30,45 and 60
The number of antennas 3 or 4
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Performance evaluation:Topological properties Average interference per network link
Average stretch factor The ratio of the shortest path lengths with
directional antennas and omni-directional antennas in the mesh network
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Average interference per link with different beamwidths
3 antennas per node
4 antennas per node
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Average Stretch factors with different beamwidths
3 antennas per node
4 antennas per node
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Packet delivery fraction for qualnet simulations (4 antennas per node)
Dense network
Sparse network
100 nodes and50 flows
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Packet delivery fraction for qualnet simulations (3 antennas per node)
Dense network
Sparse network
100 nodes and50 flows
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Conclusion This paper presented a topology control
approach to using directional antennas in wireless multihop networks. Low interference Reasonable stretch factor Increasing the end to end throughput
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