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Project Overview
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Team
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Disssemination Activity
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References
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In the
emerging information society the wireless networks and related services will
become at least as pervasive as cellular telephony is today. Therefore, it is
expected that the demand for wireless services will continue to increase in
the near and medium term, calling for more capacity and putting more and more
pressure on the spectrum availability. Considerable spectrum could be
available when both the dimensions of space and time are considered, and
hence the problem of spectrum scarcity as perceived today, is in most cases
one of inefficient spectrum management rather than spectrum shortage.
Consequently the regulatory bodies decided to investigate radically different
and more flexible access paradigms. For example, the EU parliament approved
in february 2007 a resolution that endorses spectrum liberalisation embracing
technology and service neutrality, flexibility and a secondary market and, in
USA, the FCC has expressed its interest in permitting unlicensed access to
white spaces in the tv bands. An important role in studying the
electromagnetic environment and in deciding what frequencies could be used at
a given moment comes to the receiver. The cognitive radio (CR), built on
the software-defined radio (SDR), is defined as an intelligent wireless
communication system that is aware of its environment and uses the
methodology of understanding-by-building to learn from the environment and
adapt to statistical variations in the input stimuli. This technology
could represent a promising answer to developing adequate receivers. As the
CR field has a quite short history and the standardisation activity has a
first mile stone about 2010 there exist many aspects to be developed from the
CR concept itself, to signal processing algorithms for sensing the RF
activity, adapting to new geographical environment and policies, deciding and
to the specific technologies for RF section of the receiver (analog front
end, antennas etc.). |
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