Post on 08-Apr-2018
8/6/2019 Gayaz Cognitive Radio Ppt
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A cognitive radio is a radio whose control processes permit the radio to
leverage situational knowledge and intelligent processing to
autonomously adapt towards some goal.
Cognitive radio is a paradigm for wireless communication in which either
a network or a wireless node changes its transmission or receptionparameters to communicate efficiently avoiding interference with
licensed or unlicensed users. This alteration of parameters is based on the
active monitoring of several factors in the external and internal radio
environment, such as radio frequency spectrum, user behaviour and
network state.
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Cognitive radio(CR) is an emerging concept in wireless access,
aimed at improving the way radio spectrum is utilized. It signifies a radio that employs model based reasoning to achieve a
specified level of competence in radio related domains.
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Estimation of interferencetemperature of the radioenvironmentDetection of spectrumholes
Estimation of channel-stateinformationPrediction of channelcapacity for use by thetransmitter
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It was thought of as an ideal goal towards which a Software Defined
Radio platform should evolve: a fully reconfigurable wireless Black Box
that automatically changes its communication variables in response to
network and user demands.
Regulatory bodies in various countries (including the Federal
Communications Commission in the United States, and Ofcom in the
United Kingdom) found that most of the radio frequency spectrum was
inefficiently utilized For example, cellular network bands are overloadedin most parts of the world and concluded that spectrum utilization
depends strongly on time and place. Moreover, fixed spectrum allocation
prevents rarely used frequencies (those assigned to specific services)
from being used by unlicensed users, even when their transmissions
would not interfere at all with the assigned service. This was the reason
for allowing unlicensed users to utilize licensed bands whenever it would
not cause any interference (by avoiding them whenever legitimate user
presence is sensed). This paradigm for wireless communication is known
as Cognitive radio.
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The first phone call over a cognitive radio network was made on Monday
11 January 2010 in Centre for Wireless Communications at University of
OULU using CWC's cognitive radio network CRAMNET(Cognitive
Radio Assisted Mobile Ad Hoc Network), that has been developed solelyby CWC researchers.
8/6/2019 Gayaz Cognitive Radio Ppt
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Main functions1. Spectrum sensing
Detecting unused spectrum
2. Spectrum management
Capturing the best available spectrum3. Spectrum mobility
Maintaining seamless communication duringthe spectrum transition
4. Spectrum sharing
Providing fair spectrum scheduling method
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Improving spectrum utilization & efficiency
Improving link reliability
Less expensive radios
Advanced network topologies
Enhancing SDR techniques
Automated radio resource management.
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y Improved link performancey Adapt away from bad channels
y Increase data rate on good channels
y Improved spectrum utilization
y Fill in unused spectrumy Move away from over occupied spectrum
y New business propositions
y High speed internet in rural areas
yHigh data rate application networks (e.g., Video-conferencing)
y Significant interest from FCC, DoD
y Possible use in TV band refarming
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