Ad Hoc Networks
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Introduction
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Ad
Hoc Networks are self organising, self healing, distributed networks
which most often employ wireless transmission techniques. My ongoing
research in this area is divided into two domains. The first is
airborne ad hoc networking (my doctoral research topic), the second is
Suburban Ad hoc networking.
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The Suburban Ad Hoc (Area) Networking group focusses
its
research activities on techniques for implementing Suburban Ad Hoc
Networks. These are self organising, quasi-static ad hoc (typically
wireless) networks which provide an alternative technology for
providing
high speed digital connectivity to households, small businesses and
distributed campuses. Specific areas of research interest include
security, low level routing protocols, access controls and propagation
behaviour. |
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| Smart Ad Hoc Networks |
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Smart Ad Hoc Networks are
capable of analysing the radio propagation environment they operate in
to optimise performance. This typically requires that the network nodes
have positioning capability as well as memory to recall geographically
local conditions.
GNSS systems are the most affordable approach to providing network
nodes with positioning capability.
Navstar GPS References:
Global
Positioning System Overview @ University of Colorado at Boulder.
NAVSTAR GPS Joint
Program Office (SMC/GP) Homepage
GPS Guided
Weapons - Parts I-V @ APA
Mike Tyson's Research
Page
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Airborne Ad Hoc Networks
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Airborne
Ad Hoc Networks (AAHN) are a form of ad hoc network in which the
transceivers and routers are carried by airborne platforms, such as
conventional aircraft, High Altitude Long Endurance or conventional
Uninhabited Aerial Vehicles, tethered aerostats or dirigibles. As
such the AAHN has many quite different characteristics compared to
conventional 'terrestrial' ad hoc networks. While AAHNs offer enormous
footprint coverage for each node, compared to conventional solutions,
this is achieved at the expense of unique problems in antenna
placement,
transceiver design, protocol design and integration.
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Research Publications
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| C Kopp and C S Wallace: TROPPO
- A Tropospheric Propagation Simulator, School of Computer
Science and Software Engineering, Monash University, Melbourne, 21pp.
Technical report 2004/161. Abstract
available. |
C Kopp: The
Properties of High Capacity Microwave Airborne Ad Hoc Networks, PhD Thesis,
School of Computer Science and Software Engineering, Monash University,
Melbourne, 2000, 435pp.
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Defence
Industry Publications (Network
Centric Warfare)
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Media
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Defense Industry Daily
- AESA
Comlinks: DID Reader Has Done Prior Research
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Airborne Ad Hoc Network Basics
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Perhaps
the best contextual comparison depicting the unique properties of the
AAHN is its geometry compared to conventional satcom links. With most
aircraft at the tropopause, and some in the stratosphere (UAVs) or
lower
troposhere, propagation related issues are far more pronounced against
satcom systems, while latency is inherently better, especially where
the
network footprint is relatively modest.
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This chart compares latency behaviours for
satellite systems. The AAHN at shorter distances experiences latencies
which are characteristic of terrestrial networks.
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Propagation
geometry chart for an AAHN link. The most interesting problems to solve
arise in the Loss/Gain limited and Transition regions.
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This chart depicts the coverage
requirements for an AAHN antenna suite on a conventional aircraft.
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Modelling
long range link behaviour requires simulation of propagation losses.
This plot was produced by the TROPPO simulator and depicts gaseous
losses as a function of altitude, using the Van Vleck, Liege and Blake
models.
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Fine
structure of the gaseous loss model in the Oxygen resonance region
using the TROPPO simulator.
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| Gaseous loss
rate model parameterised by frequency. |
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Gasous loss
profiles for a link between an aircraft at 11 km altitude and a ground
station, separated by a ground track distance of 380 km, using the
TROPPO simulation and a nonlinear refracted path model.
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