27-06-2012, 02:42 PM
cognitive radio technology
[attachment=25720]
WHAT IS COGNITIVE RADIO
Cognitive radio is a paradigm for wireless communication
In which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users.
This alteration of parameters is based on the active monitoring several factors in the external and internal radio environment such as,
Radio spectrum
user behaviour and network state.
SPECTRUM SENSING
In order to avoid interference the spectrum
holes need to be sensed
primary user detection, the most efficient way
Spectrum sensing techniques are divided into three categories
transmitter detection
cooperative detection
interference based detection
Transmitter Detection
signal from a primary transmitter is
locally present in a certain spectrum or not
three different approaches
– matched filter detection
– energy detection
– cyclostationary detection
Spectrum Mobility
cognitive radio user exchanges its frequency of operation
target to use the spectrum in a dynamic manner by
allowing the radio terminals to operate in the best
available frequency band
seamless communication requirements during the
transition to better spectrum must be maintained
[attachment=25720]
WHAT IS COGNITIVE RADIO
Cognitive radio is a paradigm for wireless communication
In which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users.
This alteration of parameters is based on the active monitoring several factors in the external and internal radio environment such as,
Radio spectrum
user behaviour and network state.
SPECTRUM SENSING
In order to avoid interference the spectrum
holes need to be sensed
primary user detection, the most efficient way
Spectrum sensing techniques are divided into three categories
transmitter detection
cooperative detection
interference based detection
Transmitter Detection
signal from a primary transmitter is
locally present in a certain spectrum or not
three different approaches
– matched filter detection
– energy detection
– cyclostationary detection
Spectrum Mobility
cognitive radio user exchanges its frequency of operation
target to use the spectrum in a dynamic manner by
allowing the radio terminals to operate in the best
available frequency band
seamless communication requirements during the
transition to better spectrum must be maintained