Spatial Multipath Location Aided Ad Hoc Routing

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Spatial Multipath Location Aided Ad Hoc
Routing Soumendra Nanda, Robert S Gray Department
of Computer Science, Center for Mobile Computing
Dartmouth College, Hanover, New Hampshire
INTRODUCTION There are several ad hoc routing
algorithms that utilize position information
(usually in two dimensional terms) to make
routing decisions at each node. Our goal is to
utilize three-dimensional (3D) position
information with multipath routing to provide
more scalable,efficient and reliable routing than
non position based algorithms. One of the best
known position based algorithms GPSR does not
work in 3D.

• What is GRID?
• GRID is an ad hoc routing protocol proposed by
  Liao Tseng Sheu in 2001 that uses 2D location/
  GPS info to make routing decisions
• It is hierarchical in nature (Similar to ZRP) and
  Routes are created using LAR . NOTE It is
  unrelated to the GRID Geographic Location Server
  (GRID GLS) from MIT

• Our Proposed Protocol Hyper-Grid
• GRID extended to support 3D position information
• Extended for Multi-Path Routing!
• Extends naturally to 3D, squares to cubes,
  circles to spheres.
• Inherits from GRID
• -Hierarchical nature and Scoped Flooding
• -Ability to mitigate the broadcast storm
  effect

• Research Plan Overview
• Extend 2D algorithms to 3D and study them
• Extend GRID and LAR algorithms to 3D
• Implement a hybrid variant which utilizes a
  Multipath Routing Strategy

Where we feel this protocol can be useful
Ocean Sensor Networks
Soldiers in the Field
Urban Rooftop Networks

• Imagine wireless sensors submerged at different
  depths drifting individually or as a group with
  ocean currents.
• This scenario serves as one of the base cases for
  our proposed implementation

• Imagine a city full of skyscrapers

• Less mobile than ocean sensors.
• Within a building, people probably will move
  within a floor or two for most of the time
• Accurate Position Information available for all 3
  Dimensions

Ad hoc Wireless Network
Foot Soldiers/ Rescue Workers with GPS info

• Imagine a platoon in an industrial complex or in
  a foreign city.. Or soldiers at different
  elevations, ...Imagine firefighters setting up
  comm. ad hoc as they work in a multistory sky
  scraper after a major disaster

Hyper-Grid Protocol Explained
Progress So Far

• Implementations for AODV, AOMDV, LAR-2D are
  ready in ns-2
• Implemented 3D LAR in ns-2
• Multipath LAR and GRID ns-2 code development in
  progress
• 3D random motion mobility model used for
  comparison base

Relationship Between Radio Range r and Grid
Size d LTS
Potential Drawbacks
Simple Cross Sectional View

• 3D GPS info will be required at all nodes
• A reliable Position Database/ Geographic
  Location Service (GLS) will be required.
  It is possible that implementing this service
  will have its own resource requirements, which
  can be high.
• Effect of errors in position information

Future Work
Examples of Scoped Flooding LTS
A Working Multipath Example

• Dynamic Grid Size Experiments
• Additional complex and realistic 3D Mobility
  Models
• Study of Leaders vs. Followers Battery
  Consumption Patterns
• Creating a 3D version of GPSR

LTS GRID A Fully Location Aware Routing
Protocol for Mobile Ad hoc Networks, (2001)
Wen-Hwa Liao, Yu-Chee Tseng and Jang-Ping Sheu
LAR ns-2 code provided by Dr. Tracy Camp et al,
(2002) Colorado School of Mines