QinetiQ Proprietary
QINETIQ/06/00420 Page 3
QinetiQ Proprietary
Time of
day
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Time of
day
Frequency MHz
Executive Summary
Introduction
This study has been commissioned by Ofcom to enable it to develop its strategic
response to the emerging Cognitive Radio (CR) debate, both nationally and
internationally. The study, therefore, builds on previous Software Defined Radio
reports
1,2
and considers aspects such as CR terminology, technologies, potential
development timescales, user scenarios and regulation.
The report starts with this Executive Summary which poses and responds to, a set
of questions and concludes with a number of summary recommendations ordered
into themes. The main report body contains technological, regulatory and economic
discussions and a complete list of study recommendations. The Appendices contain
technical data and flowcharts to support the main report body.
Study Background
Most of today’s radio systems are not aware of their radio spectrum environment
and operate in a specific frequency band using a specific spectrum access system.
Investigations of spectrum utilisation indicate that not all the spectrum is used in
space (geographic location) or time
3
(see spectrum usage pane below). A radio,
therefore, that can sense and understand its local radio spectrum environment, to
identify temporarily vacant spectrum and use it, has the potential to provide higher
bandwidth services, increase spectrum efficiency and minimise the need for
centralised spectrum management. This could be achieved by a radio that can make
autonomous (and rapid) decisions about how it accesses spectrum. Cognitive radios
have the potential to do this.
Spatial and temporal
spectrum usage plots
3
Diurnal and spatial spectrum
usage measurements
3
indicate that the spectrum is
not used all the time (blue
regions) and that the usage
(green regions) depends on
location.
Cognitive radios have the
potential to jump in and
out of un-used spectrum
gaps to increase
spectrum efficiency and
provide wideband
services.
1
Sturman, T.A, An Evaluation of Software Defined Radio, Ofcom 2006
http://www.ofcom.org.uk/research/ technology/overview/emer_tech/sdr/AnEvalofSDRMainDocumentv1.pdf
2
Gultchev, S et al, Evaluation of Software Defined Radio Technology, Ofcom 2006,.
http://www.ofcom.org.uk/research/technology/overview/emer_tech/sdr/eval.pdf,
3
Ofcom, Cognitive Radio Webpage, www.ofcom.org.uk/research/technology/overview/emer_tech/cograd/]
