International Telecommunication Union
Advanced Wireless Technologies
and
Spectrum Management
Taylor Reynolds
ITU Strategy and Policy Unit
Radio-spectrum Management
for a Converging World
Geneva Switzerland
17 February 2004
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The views expressed in this paper are those of the author and do
not necessarily reflect the opinions of the ITU or its Membership.
International Telecommunication Union
Spectrum scarcity
Spectrum
No technological
change
Technological
change
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Number of users
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Role of technology & policy
New technologies
Approved technologies
for spectrum use
Regulatory
Authority
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International Telecommunication Union
Policy has been lagging
z Regulation (1930)
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z Technology (2004)
¾ Built on the assumption
of “dumb” radios
¾ Fast processing power
and intelligent radios
¾ Tightly regulated use for
licensees
¾ Highly controlled
transmission power
¾ Very limited provisions
for reclaiming
inefficiently used
spectrum
¾ New technologies
•
•
•
•
Spread spectrum
Smart antenna
Mesh networks
Software defined radios
International Telecommunication Union
Spectrum management
is changing
z Policy makers realize the traditional system is
inefficient.
z Non-traditional spectrum allocations
¾ Unlicensed spectrum: very successful
¾ Auctions: mixed results
z Policy makers facing difficult decisions
¾ Integrate new technologies under the traditional
scheme
¾ Revamp the entire system.
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International Telecommunication Union
What regulators are facing
z The task of overhauling the spectrum
allocation system
z The need to understand advances in
wireless technologies.
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International Telecommunication Union
Spread Spectrum
Spread spectrum
technologies send
information over a
much wider band
than the actual
bandwidth of the
information by using
a code to either
modify the carrier
wave or to define a
hopping pattern for
frequencies.
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Image source: http://www.futaba.com/IRC/irctechlib.htm
International Telecommunication Union
Ultra-wide band (UWB)
z Ultra-wide band is a spread spectrum technology
that transmits data at very high speeds by sending
the transmission over a wide range of frequencies
but at very low power levels.
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Image source: ITU adapted fromIntel
International Telecommunication Union
Smart antennas
Smart antennas
use digital signal
processing to
pinpoint the
location of users.
This allows them
to send and
receive targeted
transmissions
and reduce
interference.
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Image source: ITU adapted from IEC
International Telecommunication Union
Mesh networks
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z A local area network
(or LAN) where each
device on the network
simultaneously
connects to and
communicates with
all devices in range.
Devices communicate
with each over by
passing
transmissions using
other devices as
intermediaries.
International Telecommunication Union
Software-defined radio
z A wireless communication device where a
computer controls the transmitter modulation.
They can be re-programmed on the fly
z Promising applications:
¾ Multiple uses from generic radio terminal
•
•
•
•
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Mobile phone
Cordless phone
Pager
WLAN
¾ Quick software upgrades to adapt to regulatory
changes
¾ Agile radios
International Telecommunication Union
Agile radios
Frequency
Agile radios act as frequency scavengers. They
can broadcast on an unused frequency until the
agile radio “senses” another radio trying to use
the same frequency. At that moment, the radio
“hops” frequency to another temporarily unused
portion of the radio spectrum.
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Time
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Key policy decisions
z Allowing underlays
z Developing interference temperature
measures
z Allowing coexistence models
z Creating more unlicensed spectrum
z Cleaning up unused spectrum
z Developing a regulatory model for mesh
networks
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International Telecommunication Union
Allowing underlays
z Benefits
¾ UWB allows highly efficient use of the noise
floor, without affecting licensed uses
¾ The wider the usable band, the lower the power
needed to transmit
¾ Could form the foundation of future mesh
networks
z Drawbacks
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¾ Strong resistance from current licensees
¾ Adding more UWB devices raises overall noise
International Telecommunication Union
Interference temperature
z Benefits
¾ Allows for a dynamic use of spectrum in a
given location, based on the current use
¾ Radios could use higher power in “quiet areas”
and reduce power or switch frequencies in
“noisy environments”
z Drawbacks
¾ Difficult to initially coordinate a system that all
devices would follow
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Coexistence models
z Benefits
¾ Can greatly increase the use of fallow spectrum
• Studies have found only 19-40% usage throughout the day on
even the most populated frequencies.
¾ Unlicensed devices could scavenge for
frequencies, subject to equipment and
regulatory controls
z Drawbacks
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¾ Strong opposition from current licensees
¾ May require upgrades of equipment for
licensees.
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Unlicensed spectrum
z Benefits
¾ Creates a fertile test bed for new wireless
technologies.
¾ Decreases the costs to technology developers
¾ Provides incentives to create devices with high
tolerance to interference (e.g. spread spectrum)
z Drawbacks
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¾ Spectrum bands can become congested
¾ Difficulty clearing new bands
¾ Loss of direct revenues to governments if
spectrum is not auctioned
International Telecommunication Union
Multi-use, software defined
radios
z Benefits
¾ Software-defined radios can reduce the number
of wireless technologies people need to carry.
¾ Radios could be updated on-the-fly to conform
to new regulations
z Drawbacks
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¾ Regulation will need to start moving away from
hardware to software.
¾ Software can be hacked out of compliance
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Mesh networks
z Benefits
¾ Reduce distance each radio needs to
broadcast
¾ Bandwidth increases with the number of
users on the network
¾ Excellent network for using UWB and smart
antennas
z Drawbacks
¾ Battery life
¾ Security concerns
¾ Regulatory implications
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International Telecommunication Union
Key recommendations
z Regulatory authorities should strongly consider
allowing UWB, at least at low power levels.
z Spectrum authorities should consider setting
aside frequencies for testing agile radios.
z Regulators should begin looking into the
ramifications of mesh networks.
z Regulators should create a technical advisory
group to follow new technologies.
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International Telecommunication Union
Thank you
Taylor Reynolds
taylor.reynolds@itu.int
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