Transcript the radio spectrum

Radio Science Issues
François Lefeuvre,
URSI President, LPCE/CNRS 45071
Orléans cedex 2, France
ESWW4 - Bruxelles – 6 November 2007
1
The radio spectrum
An exploding use for a unique
limited resource
2
1. Radio spectrum
2.Radio Science & Telecommunication
3. URSI scientific activities
4. Present issues
3
1. THE RADIO SPECTRUM
4
The Electromagnetic spectrum
5
geophysics, atmospherics,
plasma instabilities
navigation & naval comm.
Amateurs radio
emissions from astr. objects
fluct. thermal noise (radiometers)
satellite comm. and
broadcasting, Wi-Fi (5 GHz),
radars for remote sensing
plasma instabilities from planetary & Sun envir t.
TV and radio broadcasting
radars (incl. ionosph. and troposph.- stratosph. radars)
micro wave applications
6
MICROWAVES
Mobile phone: 0.9, 1.8, 1.9 GHz
GPS: 1.2, 1.5 GHz
DECT: 1.8, 1.9 GHz
Wi-fi: 2.4, 5 GHz
etc.
7
2. RADIO SCIENCE AND
TELECOMMUNICATION
8
The Birth of URSI
9
Emission at 850 kHz from Poldhu (Cornwal)
Reception at St John, Newfounland (Canada))
10
Two models were investigated
to explain the Marcony
observations :
- surface diffraction
- atmospheric reflection
In parallel,
-The Belgian kings Leopold II and Albert 1er pushed Robert Goldschmidt
to develop radio links between 2 towns of Belgium Congo and between
Belgium and Congo
-The French government investigated the possibility of a radio link between
France and Morocco
11
■ October 1913, creation of the « Commission
Internationale de TSF
■ July 1919 , creation of the « International Union of
Scientific Radiotelegraphy »,
which very soon became URSI
12
The ionosphere was discovered in the early twenties and the
propagation laws of an EM wave in a plasma were established
in the early thirties.
13
URSI
Union Radio Scientifique Internationale
International Union of Radio Science
has for objective to stimulate and to coordinate, on an
international basis, studies in the fields of radio,
telecommunication, and electronic sciences
- URSI Secretariat, c/o INTEC, University of Ghent
http://www.ursi.org
- 42 National Committees
- 10 Scientific Commissions
- several standing committees
14
URSI is an ICSU Scientific Union
ICSU (International Council for Science) is part of UNESCO. It is
considered as the “voice” of Science. It is engaged in numerous
actions concerning science and society .
It consists of :
- National Members (Academies)
- Scientific Unions (29) such as IAU (International Astronomical
Union), IUGG/IAGA (International Union of Geodesy and Geophysics
/ International Association of Geomagnetism and Aeronomy)
- Scientific Associates (19)
15
Interdisciplinary Bodies (IBs) have been created by ICSU Scientific
Unions (including URSI)
URSI in involved in
- COSPAR (Committee on Space and Research)
- FAGS (Federation of Astronomical and Geophysical Data
Analysis) and its ISES (International Space Environment Service)
service
- IUCAF (Scientific Committee on frequency Allocations for
Radio Astronomy and Space Science)
- SCAR (Scientific Committee on Antarctic Research)
- SCOSTEP (Scientific committee On Solar-Terrestrial Physics)
16
Management of the radio spectrum
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The management of the radio spectrum is under the
responsibility of
ITU
(International Telecommunication Union)
leading United Nations agency for information and
communications technologies, with 3 core sectors:
- Radio communication
- Standardization
- Development
ITU is an ICSU partner.
18
URSI, which is a sector member of ITU, pursue radio
sciences activities upstream of ITU
Professional Societies like IEEE, IEE, SEE, etc pursue R&D
activities upstream of ITU
Radioscientists belong both to ITU, URSI and professional
societies
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3. URSI SCIENTIFIC ACTIVITIES
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A. Electromagnetic Metrology

Development and refinement of new measurement
techniques
- based on EM principles (e.g. precise time and
wavelength measurements)
- or used for the characterization of EM properties of
materials and electromagnetic dosimetry
with applications in industry, environment ad security, health
and safety, communications, etc.

Primary standards, including those based on quantum
phenomena: realization and diffusion of time and frequency
standards
21
LNE &
LNE-SYRTE/OP
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B. Fields and waves, EM theory
and applications

Analytical, numerical and measurement techniques to
understand electromagnetic phenomena
- development of antennas and antenna arrays
- propagation including waves in specialized media
like Metamaterials (MTMs) where n, ε and μ can be
made <0
- application of EM fields as a non-destructive tool

Inverse scattering and imaging
23
Simulation of surface currents (F Molinet)
PO
MoM
50
40
SER VV
30
20
10
(R. W. Ziolkowski)
0
-10
-180 -150 -120 -90
-60
-30
0
30
60
90
120 150 180
theta (°)
MTMs may lead to new physics
and engineering concepts MT
Equivalent radar surface of the plane From a Physical Optic (PO) approximation
and from a numerical simulation (F. Molinet)
24
C. Radio-Communication systems
and signal processing

Research and development in:
- Radio-Communication and Telecommunication
Systems
- spectrum and medium utilization
- information theory, coding, modulation and
detection
- signal and image processing

In order to communicate with anyone, anywhere, any time
require new concepts like « reconfigurable radio and
cognitive radio ».
25
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Cognitive Radio and other Radios
Software defined radio (SDR): A radio in which RF operating parameters including but not limited to
frequency range, modulation type, or output power can be set or altered by software, and/or the
technique by which this is achieved
Policy-based adaptive
radio (PBAR): A radio
that is governed by a
predetermined sets of
rules for behaviour
that are independent
of the radio
implementation
regardless of whether
the implementation is
in hardware or
software and both
senses and adapts to
its environment.
SDRSOFTWARE
DEFINED RADIO
RADIO
COGNITIVE
RADIO
POLICYBASED
ADAPTIVE
RADIO
RECONFIGURABLE RADIO
Cognitive radio (CR): A
radio or system that
senses, and is aware of, its
operational environment
and employs knowledge
representation, automated
reasoning and machine
learning mechanisms in
establishing, conducting,
or terminating
communication or
networking functions with
other radios. Cognitive
radios can be trained to
dynamically and
autonomously adjust their
radio operating parameters
accordingly.
Reconfigurable radio (CR): A reconfigurable radio is a radio whose hardware
functionality can be changed under software control
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D. Electronics and photonics

Research of the new electronic and photonic devices
and systems permitting the development of digital
computers, Television and mobile communications, etc.
- semiconductor lasers
- optical fibers,
- microwave integrated circuits
- nano-optics and nano-electronics

Device for generation, detection, storage and
processing of EM signals together with their
applications from the low frequencies to the optical
domain
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On the announcement of the 2007
Conference of the French URSI
Committee :
- nano device for fast (20-100 µs)
commutation
- light distribution in an hexagonal
photonic crystal cavity
- scale for molecular electronic
-carbon nano-tube (diameter : ~
10 nanometers), with specific
properties (conductivity) to be used
for electronic components (e.g.
transistors).
29
E. Electromagnetic Noise and
Interference

Investigation of the level and of the effects of natural and
man-made noises on the performances of radio, TV, phones,
navigation instrument, etc.
- adaptation of test techniques to impulsive and higher
frequency noises
- questions raised by new concepts like Power Line
Communications (PLC)
- definition of new standards and norms

Terrestrial and planetary noise of natural origin, seismic
associated electromagnetic fields
30
Spectrum of the
EM noise in the
Earth environt
Application of Power Line
Communication (PLC) to the
transmission of commands within
a car
P. Degauque
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F. Wave propagation and remote
sensing

Study of wave propagation and of wave interactions in
non ionized media
- neutral atmosphere
- planetary surfaces and subsurfaces (including land,
ocean and ice)

Applications in the areas of remote sensing and
communications
32
Soil moisture from brightness
obtained with the ESTAR L-band
Radiometer (Camp and Swift)
Use of radio-interferometry
to identify ground movements
(e.g. after earthquakes),
accurate topography, etc.
Here, use of ESR1 data at
18 months difference to
Point out displacements after
The 1992 Landers quake.
Comparisons with a model
To remove uncertainties
(D. Massonnet)
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Winds in hurricanes
Tsunami ocean wave from
altimeter overpass
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G. Ionospheric Radio and Propagation

Study of the ionosphere in
order to provide the broad
understanding necessary to
support space and groundbased radio systems.





Global morphology and modeling
of the ionosphere;
Ionospheric space-time variations;
Development of tools and
networks needed to measure
ionospheric properties and trends;
Theory and practice of radio
propagation via the ionosphere;
Application of ionospheric
information to radio systems.
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Ionospheric space-time
variations

Assimilative mapping
techniques (borrowed from
the Met Community)



Examples are GAIM in the
USA
EDAM in Europe
Assimilative models take
data from various sources
and add them to a
background model in a
controlled way to generate
a current and forecast map
of the ionosphere
EDAM mapping of the October 2003 Storm.
Copyright QinetiQ
37
H. Waves in Plasmas

Study of the generation, propagation and interactions
of EM (and ES) waves with space and laboratory
plasmas and with other waves

Applications
- in the study of the variations of the
environment of the Earth and of the planets,
and of other astrophysical objects
- in Space Weather (spacecraft-plasma
interactions, modeling of the radiation belts)
38
Waves and turbulences play a
fundamental role in the dynamics
of particles in the sun corona, the
solar wind, the planetary and Earth
environment, etc.
Electromagnetic waves in
plasma may be the signature
of man-made noise (in red,
effects of ground based
transmitters in the
frequency range : 18 – 22
kHz)
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J. Radio Astronomy

Observation and interpretation of all radio
emissions and reflections from celestial objects

Emphasis is placed on:
- the promotion of technical means for making
radio-astronomical observations and data
analysis
- support of activities to protect radioastronomical observations from harmful
interference
40
Our beautiful radio universe
Cygnus A
a radio galaxy
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New designs for dishes + single pixel
feeds
USA
15 m fibreglass+foam
dish (<2mm rms)
6m hydroformed
dish
Canada
10 m composite
dish
South Africa
42
K. Electromagnetics in biology
and medicine

effects of and mechanisms involved with exposure of
biological systems (in general) and of humans (in
particular) to EM waves

Applications to
- studies on effects of radars, power lines, cell
phones
- medical use of exposures to EM
43
Exposure (microTesla)
EM Pulses from 0.1
to a few 100 Hz are
non-ionizing but
are able to induce
significant
biological currents
in tissues.
300
Fast Rise
Refractory Period
200
100
0
-100
-200
-300
0
Pulse Segment
500
1000 3000
Time (msec)
3500
Some treatments: Bone formation / fractures, Cancer , (tumour growth), congenital
pseudarthrosis, depression, joint disorders, nerve regeneration, osteoarthritis, Pain
(Thomas et al.)
Portable
Magnetic
Field Exposure
Unit
Dedicated devices and models
are used to simulate phenomena
produced by the interaction of
EM fields with surrounding
objects, human tissues, …
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4. PRESENT ISSUES
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Reduce the gap between
Telecommunication and Radio Science
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Demands for a more operational use of the radio spectrum exists.
Cognititive radios and other radios allow that evolution.
The point is the full implementation of predetermined sets of rules
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Forum on
Radio Science and Telecommunications
URSI – General Assembly – Chicago (11-16 August 2008)
- General Lecture (Friday 15, 11.00 – 12.00)
Wireless Communications in 2020
- Forum (Friday 15, 13.40 – 17.20)
- Cognitive radio
- Ultra wide band
- Interference management
- health aspects
- open discussion
48
Develop Radio Science in developing
countries
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




The radio spectrum is a unique common limited
resource (developing countries included)
Its management require agreements between all users
(radioscientists included)
Except in specific cases (e.g. the existence of
international equipments) developing countries
generally don’t invest on radio science
The point is to identify priorities for development in
radio science
The three ICSU Regional offices (Africa, Asia, Latin
America and Caribbean) have defined priorities. The
common one : “Natural and Human induced hazards
and disasters”
50
ICSU list of hazards and disasters
- hazards related to hydrometeorological and geophysical trigger events,
i.e. earthquakes, volcanoes, flooding storms (hurricanes, typhoons, etc.)
- heat waves
- droughts and fires
- tsunamis
- coastal erosion
- landslipes
- aspects of climate change (for example, increases of extreme events)
- space weather and impacts by near-Earth objects
- and related events such as wild fires and locust outbreaks
- The effects of human activities on creating or enhancing hazards,
including land-use practices should be included
51
Possible involvement of URSI in disaster
management
WG to study and develop guidelines related:
(a) to communication systems to set up at the time
and after disaster,
(b) to the use of remote sensing data for:
- monitoring and alert,
- description of the disturbed environment at
the time of disaster
- description of the environment after the time
of disaster
52
Answer societal demands for
« objective » information
(without expressing position or/and support)
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White paper on SPS (June 2007 Radio Science Bulletin issue)
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The SPS concept

Solar energy is collected in space by a satellite in a
geostationary orbit

The solar energy is converted to direct current by solar cells

The direct current is in turned used to power microwave
generators in the GHz frequency (microwave) range

The generators feed a highly directive satellite-borne
antenna, which beams the energy to the Earth

On the ground, a rectifying antenna (rectenna) converts the
microwave energy from the satellite into direct current

After suitable processing, the current is fed to the power
grid
55
Typical SPS unit :
- solar panel area of ~10 km2
- transmitting antenna of ~ 2 km diameter
- rectenna ~4 km in diameter
- electric power output ~ 1 GW
56
Among the points addressed in the URSI WP:
- comparison of the output power from a space-based and a terrestrialbased solar power unit
-required technology
- required pointing accuracy
- effects of solar-wind particles and solar radiation on solar cells
- lifetime and maintenance
- linear and non-linear interactions of the microwave beam with the
atmosphere, the ionosphere and the space plasmas
- safety measures
57
Actions in progress about a White Paper on:
Wireless communication and health
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