2. 2
Overview
Software Defined Radio & Cognitive Radio
Techniques for Cognitive Radio
Access Models
Opportunities for Ireland?
3. Software Defined Radio (SDR)
A radio transmitter and/or receiver employing a
technology that:
allows the RF operating parameters including, but
not limited to, frequency range, modulation type, or
output power to be set or altered by software,
excluding changes to operating parameters which
occur during the normal pre-installed and
predetermined operation of a radio according to a
system specification or standard
Source: ITU-R Study Group 1
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4. Cognitive Radio System (CR)
A radio system employing technology that allows the
system:
To obtain knowledge of its operational and
geographical environment, established policies and
its internal state;
to dynamically and autonomously adjust its
operational parameters and protocols according to
its obtained knowledge in order to achieve
predefined objectives; and
to learn from the results obtained
Source: ITU-R Study Group 1
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5. Techniques for Cognitive Radio (1)
Spectrum Sensing
Sense radio signals from other (nearby) radio transmitters; adjust
radio transmission parameters dynamically
Failure to detect in-band transmitter leads to interference - the
so-called “Hidden Node” problem:
Obstacle
Device A
Cognitive
Radio
Transceiver
Device B
Transmitter
Device C
Receiver
Transmission from A
interferes with
reception of C
A cannot sense B
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6. Techniques for Cognitive Radio (2)
Location Awareness & Geo-location Databases
Each Cognitive Radio device is able to determine its location and
the location of other transmitters or receivers
Tries to avoid the Hidden Node problem by consulting a central
database of nearby transmitters and adjusting radio parameters
to avoid interference
Requires database(s) to be maintained; challenging
Cognitive Pilot Channel (CPC)
Dedicated carrier providing frequency usage information for the
intended band in a given area. (CPC could be within the intended
band or an internationally designated frequency outside the band)
Requires Availability, Reliability, Accuracy & Security of the
information
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7. Access Models
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Source: Ministry of Economic Affairs, The Netherlands
(OSA = Opportunistic Spectrum Access
Frequency bands &
technical conditions
identified & defined
by regulator
•Framework for trading /
leasing of spectrum rights
defined by regulator.
•Spectrum identified by
primary licensed users
8. Opportunities for Ireland?
‘Spot market’ software tools
Database hosting
Test and Trial Ireland – for trying out
technology/applications
www.testandtrial.ie
Other?
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