GEOCASTING IN MOBILE AD
HOC NETWORKS LOCATIONBASED MULTICAST
ALGORITHMS
指導教授：許子衡 教授
學生：翁偉傑
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Young-Bae Ko and Nitin H. Vaidya Department of
Computer Science Texas A&M University College Station,
TX 77843-3112, USA fyoungbae,vaidyag@cs.tamu.edu
OUTLINE
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Abstract
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Location-Based Multicast (LBM)Protocols
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Simulation
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Optimizations of Location-Based Multicast
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Conclusion
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ABSTRACT
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This paper addresses the problem of geocasting
in mobile ad hoc network (MANET)
environments.
Describes proposed approach for location-based
multicasting in MANET.
Finally, We present two different algorithms for
delivering packets to such a group, and present
simulation results.
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LOCATION-BASED MULTICAST
PROTOCOLS (1/5)
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Multicast Flooding
不理會目的的地區，直接廣播給所有的節點，
每個接收端都會確認自己是不是在目的地區裡。
This algorithm would be very
simple and robust but would not be
very efficient.
we attempt to reduce the number
of nodes, outside the multicast
region.
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LOCATION-BASED MULTICAST
PROTOCOLS (2/5)
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Multicast Region and Forwarding Zone
Location Information
Location information
used in our protocol may
be provided by the global
positioning system (GPS) ,
utilizes location
information to reduce
multicast delivery
overhead.
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LOCATION-BASED MULTICAST
PROTOCOLS (3/5)

Multicast Region and Forwarding Zone
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LOCATION-BASED MULTICAST
PROTOCOLS (4/5)
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Location-Based Multicast (LBM) Scheme 1
Forwarding zone 大小：
-destination region
-sender location
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LOCATION-BASED MULTICAST
PROTOCOLS (5/5)
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Location-Based Multicast (LBM) Scheme 2
LBM Scheme 2: Unlike scheme 1,
scheme 2 does not have a
forwarding zone explicitly.
this protocol ensures that every
transmission of data sends the data
closer to the destination.
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SIMULATION (1/4)
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MaRS( Mary-land Routing Simulator )
Number of nodes in the network was chosen to be
30.
The nodes in the mobile ad hoc network are
confined to a 1000 unit x 1000 unit square region.
Each node moves with an average speed v.
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SIMULATION (2/4)
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For the simulations, transmission range values of
200, 250, 300 and 400 units were used.
Each simulation run simulated 1000 seconds of
execution.
We assume that the multicast region is a 300
unit x 300 unit square region.
LBM1和LBM2
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SIMULATION (3/4)
Simulation Result
LBM1
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較小的傳送路徑，成功率較大
SIMULATION (4/4)
Simulation Result
LBM2
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傳輸距離增加，flooding 增加
OPTIMIZATIONS OF LOCATIONBASED MULTICAST (1/4)
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Alternative Definitions of Forwarding Zone
兩種方式定義一個轉發區總是平
行於 X和Y軸
one side of the rectangle may be
made parallel to the line
connecting the location of
source node S to the geometric
center of the multicast region.
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OPTIMIZATIONS OF LOCATIONBASED MULTICAST (2/4)
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Forwarding Zone Adaptation
location-based multicast
scheme 1 ： 調整轉送區
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OPTIMIZATIONS OF LOCATIONBASED MULTICAST (3/4)
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Forwarding Zone Adaptation
when the forwarding zone is
defined as a cone rooted at
node S, such that angle made
by the cone is large enough to
include the forwarding zone.
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OPTIMIZATIONS OF LOCATIONBASED MULTICAST (4/4)
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Use of Directed Antennas
This inherent limitation can be
mitigated by using directed
antennas whose radiation
pattern is not omnidirectional.
multicast data packets 多播
數據包只能針對一小群的移
動節點。
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CONCLUSION
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We propose two location-based multicast
algorithms, limit the forwarding space for a
multicast packet to the so-called forwarding zone.
Simulation results indicate that proposed
algorithms result in lower message delivery
overhead, as compared to multicast flooding.
it is possible to achieve accuracy of multicast
delivery comparable with multicast flooding.
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