Proponent Team

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EHF Channel Sounding for Telecommunications
Applications via HAPs and Balloons
E. Cianca, M. Lucente, E. Morelli, T. Rossi,
M. Ruggieri University of Rome Tor
Vergata CNR INAF / IAF Bologna
Speaker Dr. Ernestina Cianca
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Outline

• Overview of the use of Balloons in the
  communication field
• Why EHF for communications via satellite?
• HAP for EHF channel sounding
• Aero-WAVE mission
• Balloons Advantages and Challenges
• Conclusions

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Overview of the use of Balloons in the
communication field
Channel characterization for satellite
communications
Some examples The University of Surrey
undertook a feasibility study (1988), for the
European Space Agency (ESA), for conducting a
multi-band propagation experiment for land mobile
satellite communication services at elevation
angles greater than 50o Balloons have been
chosen for the experiments Propagation
measurements of about 6- 10 hours at 50' -90
elevation angles are expected to provide
reasonably representative data for high elevation
angle characterization in LMS channel Lower
costs and logistics more maneagable were the main
reason to choose Balloons instead of Helicopter
and Airships - the elevation angle cannot be
controlled. However, adopting particular flight
strategy and mobile location area can help
maintaining elevation angle within a desired
range.
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Overview of the use of Balloons in the
communication field

• Testing of HAP-based comunication networks
  (commercial and military applications)
• There has been a lot of talking about the use of
  High Altitude Platforms (HAPs) as a component of
  the future communication infrastructure
• The term HAPs includes airships, airplanes
  (manned or unmanned) and also balloons operating
  in the stratosphere (17-22km)
• However, in this context it is mainly meant as
  airship or airplane

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Overview of the use of Balloons in the
communication field
Testing of HAP-based comunication networks
(commercial and military applications)

• They appear in a roughly fixed position thus
  fulfilling the role of either a very tall radio
  mast or a very low geostationary satellite
• Capable of providing long endurance services,
  either with craft which can stay there for
  extended periods (months or years) or through
  regular substitution

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Overview of the use of Balloons in the
communication field
Testing of HAP-based comunication networks
(commercial and military applications)

Low launch and maintenance costs Rapid
deployment, new HAPs and payload can be provided
more quickly than new satellites or installing
large terrestrial infrastructures Extreme
flexibility the possibility of reconfiguring
platforms or payloads in order to satisfy various
topologies of services during different periods
and in different regions.
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Overview of the use of Balloons in the
communication field
Testing of HAP-based comunication networks
(commercial and military applications)
In 2005, the European CAPANINA research
consortium, led by the University of York, has
used a stratospheric balloon for high altitude
trials in northern Sweden on a broadband
communication systems designed for HAPs. Carlo
Gavazzi Space co-ordinated the trials at the
Swedish Space Centre at Esrange and took care of
the a stratospheric balloon.Trials using radio
and optical communications equipment were carried
out, using a 12,000 m3 balloon, flying at an
altitude of around 24 kilometres for nine hours.
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Overview of the use of Balloons in the
communication field
Testing of HAP-based comunication networks
(commercial and military applications)
The lightweight, low-cost, high speed broadband
wireless access radio link equipment was designed
and developed by the University of York to
operate in the mm-wave band (28/29GHz). This
supported data rates of 11Mbit/s and throughputs
up to 4Mbit/s, using WiFi (IEEE802.11b), at
distances ranging up to 60km.The trial was a
multi-partner collaboration including University
of York (UK), Carlo Gavazzi Space (IT), DLR (D)
and CSEM (CH). Further research work continues
and additional trials are planned in conjunction
with the Japanese partners (NICT and JSC).
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Overview of the use of Balloons in the
communication field
Testing of HAP-based comunication networks
(commercial and military applications)
A tethered balloon facility to address HAPS
communication system and propagation blockage
issues for use by UK industry and the research
community has been conceived
To establish the performance that could be
expected from a High Altitude Platform based
communication system, and to assist in an
evaluation of the manner in which such systems
would be operated in practice.

• Advantages of a permanent elevated platform test
  facility
• Licensing and permission to fly issues would be
  the responsibility of the facility operator.
• The platform would be available for use at short
  notice to take advantage of particular weather
  conditions.
• A suitably selected site would give access to a
  wide range of environments for testing purposes.

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Overview of the use of Balloons in the
communication field
SKYMESH ad hoc communication system for
providing a communication network backbone in
emergencies is built with balloons that are
50-100 meters high over ground
Experiments with a tethered balloon have been
performed in 2005 at the University of Niigata,
Japan The tethered balloon stays in almost the
same position constantly over the ground for
several days and even more if more gas is added
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Why EHF band for communications via satellite?

• EHF satellite communications, in particular Q/V
  bands (35-75 GHz) and W band (75-110 GHz), could
  bring important benefits such as
• Available bandwidth, with respect to saturated
  lower frequency band
• High security level in terms of protection and
  interference through the use of very narrow spot
  beams, increasing also down-link power flux
  density and saving satellite power
• Mass and size saving, EHF are particularly
  attractive with respect to realisation of
  portable terminals and smaller satellite
  payloads, for example in the context of space
  exploration, where mass and size are one of the
  most important missions driver.

• The main drawback of these satellite links is the
  large atmospheric fade experienced when rainfall
  occurs along the path, in addition to the gaseous
  atmospheric absorption by oxygen and water vapour

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Why EHF band for communications via satellite?

• Propagation channel characterisation has been
  performed up to 50 GHz, there are no measurements
  in W band
• Identification of the most suitable PIMT
  (Propagation Impairments Mitigation Techniques)
• Innovative Missions, for EHF satellite
  communications - innovative technology
  performance evaluation

ITU-R used to obtain preliminary PDF assessment
(1st order statistics)
Additional Attenuation for different elevation
angles _at_ 86 GHz, Rome
Very low service availability
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HAP for EHF channel sounding

• The troposphere attenuation, due to rain, clouds,
  fog, atmosphere gases, is the main phenomenon
  that could limit the exploitation of this
  frequency band,
• measurements collected by the HAP experiment
  could already give significant data for the
  design of future LEO/GEO missions in W-band
• in a shorter time (1 year for flight planning
  and authorization wrt to 10 years of a GEO
  mission)
• and with a low cost (around 250.000 Euro with a
  manned aircraft with a balloons? probably much
  less)

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HAP for EHF channel sounding Aero-WAVE mission
ASI funded a study to design a payload in W-band
to be embarked over a Russian manned aircraft,
Geophysica 55 from STM-Ltd, for preliminary
channel characterization.
Aero-WAVE mission
The aircraft altitude will be around 17-20 km.
The flight route will have a diameter of about
10-20 km with an aircraft roll angle variable
from 6 to 26, due to the maneouvers that have
to be performed by the pilot in order to
counteract winds upheaval.
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HAP for EHF channel sounding Aero-WAVE mission

• Challenges
• Stability of the platform! It is very important
  for W-band since the footprint is pretty small
  (around 500m of diameter)
• A lot of attention has been spent in the design
  of the antenna and the pointing system
• Narrow beam high gain lens antenna with a
  mechanical pointing system which could be
  controlled with this approach
• tracking the ground station by calculating the
  correct pointing direction through an algorithm
  based on the a-priori knowledge of the station
  position, of the aircraft GPS positioning data
  and attitude data (roll, pitch and heading
  angles) provided by M-55 navigation system

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HAP for EHF channel sounding Aero-WAVE mission

• Other challenges
• Each flight has a duration of 5-6 hours. In this
  short time it is not easy to get significant
  statistical data under different weather
  conditions and seaons.
• However, in W-band there is nothing so far and
  also those preliminary data are very important
• Experiments at different elevation angles would
  be important to verify the validity of
  theoretical models (i.e. secant law).
• This is easy done.
• Additional costs and logistic problems due to
  the fact that it is manned

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HAP for EHF channel sounding Balloons
What about using a stratospheric Balloon? The
weight of the designed payload is lt 15Kg This is
not an issue for the balloons..so, we can reuse
this part of the work unless some changes are
needed Duration of each flight could be up to
24hrs (not antartic area) To have different
campaigns at different elevation angles is
possible
Main advantage
No need of a pilot lower cost Less
logistics problems (no need to have complex
procedure to avoid his radiation)
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HAP for EHF channel sounding Balloons
Challenges
Main problem stability of the platform The best
it would be to have it fixed in one position and
this is not possible However,
the requirements in terms of pointing capability
for our propagation experiment are expected to be
less stringent than the ones for an experiment
requiring a telescope.so, solutions foreseen for
other missions should be fine for us The choice
of the launch area (for instance, Antartic areas
are not interesting for our experiments) and the
flight strategy (kind of circle of a certain
diameter) have to be made very carefully
Some more detailed analysis is needed!
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Conclusions

• Balloons have been already successfully used for
  both propagation and communication experiments
  both for satellite and HAP
• A study of propagation and communications in EHF
  band via balloons would be very significant and
  has a great strategic importance
• first significant data for channel
  characterization in W-band
• tests on the use of this pretty new technology
• For future experiment with balloons can reuse
  most of the work already done for the design of a
  payload for a manned aircraft.
• Other challenges have been identified which
  require a deeper analysis. However, feasible
  solutions are foreseen.
• Very attractive for us!

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Questions?
Suggestions?